JP2005006280A - Amplifier for television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly convenient television receiver amplifier that can adequately set the gain without complicated gain adjustment. <P>SOLUTION: In a television receiver amplifier 10 which has an amplifier circuit 15 to amplify the inputted television signals and a branch circuit 16 to branch a part of the television signals after amplified between the inputs 11 and output 12, another switch 14 is provided between the input 11 and the amplifier 15. By using this switch 14, it is possible to decide to supply the inputted television signals to the amplifier circuit 15 directly through a pass line 19, or to supply them after attenuating in the high frequency attenuator. Further, the automatic gain control 20 controls the attenuation of the high frequency attenuator 221 to maintain the distortion in the amplifier circuit 15 within the prescribed range following the output level of the branch circuit 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a television receiving amplifying device for amplifying television signals (high frequency signals) of a plurality of channels having different frequencies.

  In a television reception system in a building or home, a television reception amplification device (hereinafter also simply referred to as “amplification device”) for amplifying a television signal received by an antenna and transmitting it to a television receiver is usually provided. If the gain adjustment of the amplifying device is not properly performed, for example, when the input signal strength is strong, the amplifying device is saturated and harmonics and distortion are generated, and the television receiver normally receives the television broadcast. There is a risk that it will not be possible. Therefore, in order to normally receive a television broadcast by the television receiver, it is necessary to appropriately adjust the gain of the amplifying device or optimize the input signal level.

  However, when adjusting the gain of the amplifying device, it is necessary to adjust to a more appropriate input level and gain according to the place of use, electric field strength, and the like, and the amount of adjustment and the contents of adjustment differ depending on the installation location. For this reason, when installing the amplifying apparatus, complicated gain adjustment work is involved, and in general, skill is required for construction.

  In view of this, a TV booster configured to display when the intensity of a TV signal is high has been proposed so that normal reception cannot be performed by the TV receiver due to a gain setting error or the like. Specifically, an attenuator and an amplifying circuit are provided between the input and output terminals. In a booster that amplifies the input signal by the amplifying circuit after the input signal is attenuated by a predetermined level, the intensity of the TV signal input from the antenna is increased. It is configured to detect and determine whether or not it is larger than a preset reference value, and display on the display unit based on the determination result (see, for example, Patent Document 1).

According to the television booster described in Patent Document 1, whether or not the input television signal is larger than a preset reference value is confirmed based on the display content (lighting on / off) of the display unit (light emitting diode). For example, if the input level is small and the light emitting diode is not lit, set the attenuation amount of the attenuator to a small value to increase the gain of the booster as a whole. When the light-emitting diode is turned on due to a large value, the gain can be adjusted while checking the input level, such as decreasing the gain of the booster as a whole by setting a large amount of attenuation of the attenuator. Therefore, it is possible to provide a TV booster with few gain setting mistakes and good mountability.
JP-A-9-130686

  However, in the television booster described in Patent Literature 1, the input level does not become larger than the reference value preset in the booster according to the installation location of the booster and the electric field strength, that is, the display unit is The attenuator is adjusted so that it is not displayed.For example, when considering the case where the terminal level is to be as high as possible while considering distribution loss in the home, the maximum is within the range where the input level does not exceed the reference value. It is also conceivable to adjust the amount of the attenuator so that the input level is input, that is, to set the attenuation amount as small as possible.

  In such a case, if the input level fluctuates greatly and an input signal larger than the specified value is input to the booster, the booster will saturate and harmonics and distortion will occur beyond the standard range. It is conceivable that normal reception of television broadcasts cannot be performed on the machine. At this time, even if there is no TV broadcast reception failure in the television receiver, the display unit provided in the booster will continue to display that the input level is over, causing distrust to the user. There was a problem.

  On the other hand, as a booster that can appropriately cope with fluctuations in the input level, an automatic gain adjustment circuit (hereinafter referred to as “AGC circuit”) using peak value detection is provided to compensate for the output level so that the output level becomes constant. Amplifying devices are known. This is to detect the peak value of the output signal (that is, the amplified signal) from the amplifying unit constituting the amplifying device and adjust the gain of the amplifying unit based on this peak value to control the output level to be constant. It is.

  However, even in the case of an amplification device configured in this way, for example, when the number of channels increases without changing the peak voltage, the combined power of the input signal increases, and in some cases, distortion of the amplification unit may occur. Although it is possible that the rate exceeds the standard value, there is still a problem that the AGC circuit based on peak value detection is activated to maintain the output level.

  In particular, in recent years, terrestrial digital broadcasting has been newly started, and channels of terrestrial digital broadcasting have been increased in the UHF band of conventional analog broadcasting in addition to conventional analog broadcasting waves. At this time, even if the television receiver is receiving the analog broadcast normally when the analog broadcast is received, the signal of the analog broadcast and the digital terrestrial broadcast is added to the input signal. It is conceivable that the combined power exceeds the maximum input level of the television receiving amplifier. There is a problem that the amplification device is saturated due to the increase of the combined power, and harmonics and distortions exceed the standard value, and the television receiver cannot receive the television broadcast normally. Therefore, it is necessary to make an adjustment while looking at the display unit so that the appropriate input level is obtained again.

  The present invention has been made in view of the above problems, and is highly convenient for TV reception amplification that can appropriately adjust the gain without performing complicated gain adjustment even if there is a difference in the TV signal level depending on the installation location. An object is to provide an apparatus.

  The invention according to claim 1, which has been made to solve the above problems, is a television reception amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side. Signal attenuating means for attenuating the TV signal input from the input terminal, amplifying means for amplifying the TV signal attenuated by the signal attenuating means, and the TV signal amplified by the amplifying means to the output terminal side An output branching unit for outputting and branching a part of the amplified television signal, and a television signal branched by the output branching unit so that the television signal amplified by the amplification unit has a predetermined level. An automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means, and a manual for manually setting the attenuation amount of the signal attenuating means continuously or stepwise. Comprising a gain adjustment means, and a control method switching means capable of switching selectively one of the automatic gain control unit or the manual gain adjustment means.

  The automatic gain adjustment means includes a signal level detection unit for detecting the television signal branched by the output branching unit, a detection voltage obtained by the detection by the signal level detection unit, and a predetermined control signal. When the detection voltage is larger than the control reference voltage by comparing with a reference voltage, an arithmetic unit that controls the attenuation amount of the signal attenuation means by outputting a control signal of a level corresponding to the detection voltage; The attenuation amount of the signal attenuation unit is controlled by either the automatic gain adjustment unit or the manual gain adjustment unit selected by the adjustment method switching unit.

  According to the television reception amplifying device having the above-described configuration, the automatic gain adjustment means can obtain an optimum output level with respect to an increase in combined power due to a level fluctuation of an input television signal or an increase in input wave number, and a manual operation. It also has a function capable of gain adjustment by the gain adjusting means. For this reason, it is easy to install without selecting an installation location or requiring complicated gain adjustment at the time of installation, and it is possible to select more appropriate and appropriate installation conditions depending on the location of the installation work and the installer. It is possible to provide a TV reception amplifying device with high performance.

  The invention according to claim 2 is a television receiving amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side, and an amplifying means for amplifying the television signal; Output branching means for outputting the television signal amplified by the amplification means to the output terminal side and branching a part of the amplified television signal, and a signal for attenuating the television signal input from the input terminal Attenuating means and the television signal input from the input terminal are attenuated by the signal attenuating means and then the attenuated television signal is output to the amplifying means side or not via the signal attenuating means. A transmission path switching means for selectively switching the output to the amplification means side, and a television signal attenuated by the signal attenuating means by the transmission path switching means. The attenuation amount of the signal attenuating means based on the television signal branched by the output branching means so that the television signal amplified by the amplifying means becomes a predetermined level when selected to output to the amplifying means side And automatic gain adjusting means for controlling.

  The automatic gain adjusting means includes a signal level detection unit for detecting the television signal branched by the output branching unit, a detection voltage obtained by the detection by the signal level detection unit, and a predetermined control reference voltage And when the detected voltage is larger than the reference voltage for control, an arithmetic unit that controls the attenuation amount of the signal attenuating means by outputting a control signal of a level corresponding to the detected voltage. .

  According to the television reception amplifying device having the above configuration, the automatic gain adjustment means is provided, so that it is optimal for various situations of input levels such as input level fluctuations and increase of combined power due to increase of input wave number. Output level is obtained. Moreover, since it is possible to arbitrarily select whether or not to use signal attenuation means, for example, when using in an area where automatic gain adjustment is not required, such as when installing in a weak electric field area, without using signal attenuation means. By directly inputting the television signal to the amplification means, the television reception amplification device can be used as a low noise amplification device, and it is possible to provide a versatile television reception amplification device that can be used in a wide range of installation locations. .

  A third aspect of the present invention is the television receiving amplifying apparatus according to the second aspect, wherein the first comparing means for comparing the detected voltage with a predetermined first reference voltage for comparison, First display means for displaying a comparison result by the comparison means, and the first reference voltage for comparison is the signal level detection unit when the television signal amplified by the amplification means is at a predetermined level. It is comprised so that it may set to the detection voltage value from.

  According to the television reception amplifying device having the above configuration, the strength of the input level of the television signal can be determined at a glance from the display content of the first display means. Based on this display content, it is possible to appropriately select whether or not the input television signal is attenuated by the signal attenuating means, and the installation can be easily performed without selecting the installation location or the installer. It is possible to provide a TV receiving amplifying device with high performance.

  Next, a fourth aspect of the present invention is the television receiving amplifying device according to any one of the first to third aspects, wherein the control signal output from the arithmetic unit and a predetermined second reference voltage for comparison are provided. And a second display means for displaying a comparison result by the second comparison means. And the second reference voltage for comparison is when the distortion factor of the amplifying means is within a predetermined standard range, and the television signal amplified by the amplifying means is at a preset maximum level. The voltage value of the control signal from the arithmetic unit is set.

  According to the television reception amplifying device having the above-described configuration, it can be seen at a glance that the output level from the amplifying means is a level where the distortion rate of the amplifying means exceeds a predetermined standard range depending on the display content of the second display means. It can be made. Therefore, it is possible to provide a television receiving amplifying apparatus that can quickly take appropriate measures such as adding an attenuator.

  By the way, as described above, due to the start of terrestrial digital broadcasting and the like, the electric field strength in the vicinity of a transmission tower that transmits television broadcast radio waves becomes higher than before. Therefore, the difference in electric field strength due to the difference in the installation location of the amplification device also becomes large, and it is not possible to cope with only one amplification device, for example, preparing an amplification device for strong electric field and an amplification device for weak electric field separately, It is expected that it will be necessary to use them according to the electric field strength at the installation location. However, it is not preferable from the viewpoint of workability and cost to prepare a plurality of types of amplifying devices according to the electric field strength in this way.

  Therefore, for example, as described in claim 5 or 6, an input attenuation means may be further provided in the input stage. That is, the invention according to claim 5 is the television receiving amplifying device according to any one of claims 1 to 4, wherein the television input to the input terminal is between the input terminal and the signal attenuation means. An input attenuating means for attenuating a signal and outputting the signal to the signal attenuating means is provided.

  A television reception amplifying device according to claim 6 is a television reception amplification device for amplifying a television signal received by a television broadcast wave reception antenna and transmitting the amplified signal to a terminal side. A signal attenuating means for attenuating the input television signal, an amplifying means for amplifying the television signal attenuated by the signal attenuating means, and outputting the television signal amplified by the amplifying means to the output terminal side Output branching means for branching a part of the amplified television signal, and the signal attenuation based on the television signal branched by the output branching means so that the television signal amplified by the amplification means becomes a predetermined level. Automatic gain adjusting means for controlling the amount of attenuation of the means.

  The automatic gain adjusting means includes a signal level detection unit for detecting the television signal branched by the output branching unit, a detection voltage obtained by the detection by the signal level detection unit, and a predetermined control reference voltage And when the detected voltage is larger than the reference voltage for control, a calculation unit that controls the attenuation amount of the signal attenuating means by outputting a control signal of a level corresponding to the detected voltage. Furthermore, input attenuating means for attenuating a television signal input to the input terminal and outputting it to the signal attenuating means is provided between the input terminal and the signal attenuating means.

  In the television reception amplifying device according to any one of claims 5 and 6, since the input attenuating means is provided separately from the signal attenuating means, the attenuation amount of the input attenuating means is adjusted according to the electric field strength at the installation location. As a result, the dynamic range of the input signal is widened, and it is possible to use the same amplifying apparatus in places where the electric field strength is high and low.

  Here, when installing in a place where the electric field strength is low, the attenuation amount of the input attenuating means may be adjusted to be low, but in some cases, this input attenuating means may not be required at all. Accordingly, in the television receiving amplifying device according to claim 5 or 6, the television signal input to the input terminal is attenuated by the input attenuating means and then the signal is inputted, as in claim 7, for example. It is provided with an input side path switching means that can selectively switch either one of the output to the attenuation means or the output to the signal attenuation means without passing through the input attenuation means. Good.

  According to the television receiving amplifying apparatus configured as described above, when the electric field strength at the installation location is high, the TV signal may be attenuated by the input attenuating means. If it is sufficient, it is sufficient that the attenuation by the input attenuating means is not required, so that it is possible to more appropriately cope with various electric field strengths.

  The switching by the input side path switching means can be manually performed by, for example, a construction worker. However, for example, as described in claim 8, the switching is automatically performed according to the level of the input TV signal. It may be.

  That is, the invention according to claim 8 is the television reception amplifying device according to claim 7, wherein the branching is performed by the input branching means for branching a part of the television signal inputted to the input terminal. Input detection means for detecting the received television signal, and input comparison means for comparing the detection voltage obtained by the detection by the input detection means with a predetermined input reference voltage. The input side path switching means outputs the input television signal as it is to the signal attenuating means when the input comparison means determines that the detected voltage is lower than the input reference voltage, and the input comparison means When the means determines that the detected voltage is equal to or higher than the input reference voltage, the input television signal is attenuated by the input attenuating means and then output to the signal attenuating means.

  According to the television reception amplifying apparatus configured as described above, when the electric field strength is low and the input level is small, the signal is output to the signal attenuating means without passing through the input attenuating means, and when the electric field strength is high and the input level is large. Since the signal is attenuated by the input attenuating means and then output to the signal attenuating means, it is possible to perform an appropriate gain adjustment according to the electric field strength without imposing a burden on the installer.

  On the other hand, the television reception amplifying device according to claim 5 or 6 is configured so that the attenuation amount of the input attenuation means is automatically adjusted according to the input signal level, for example, as described in claim 9. Also good. That is, the television reception amplifying device according to claim 9 is an input branching unit for branching a part of the television signal input to the input terminal, and an input detection unit for detecting the television signal branched by the input branching unit. And an input comparison means for comparing a detection voltage obtained by the detection by the input detection means with a predetermined input reference voltage and outputting a signal according to the comparison result, and the input attenuation means Is configured such that the amount of attenuation is controlled in accordance with the signal from the input comparing means.

  According to the television reception amplifying apparatus having the above-described configuration, not only whether or not the input attenuation means is passed as in the eighth aspect but also the attenuation amount of the input attenuation means depends on the level of the input television signal. Therefore, for example, it is possible to control the amount of attenuation to increase as the input level increases, and it is possible to perform gain adjustment more appropriately.

  In the inventions of the fifth to ninth aspects, by providing the input attenuation means in addition to the signal attenuation means, the dynamic range of the input signal can be expanded. For example, as in the tenth or eleventh aspect, Also, the dynamic range of the input signal can be expanded.

  That is, the invention according to claim 10 is the television receiving amplifying device according to any one of claims 1 to 4, wherein the amplifying means comprises a plurality of stages of amplifying units for amplifying the input television signal. Each amplifying unit is provided with switch means for short-circuiting the input and output of the amplifying unit. And an input branching unit for branching a part of the television signal input to the input terminal, an input detection unit for detecting the television signal branched by the input branching unit, and the detection by the input detection unit. And amplifying unit control means for controlling the state of the switch means corresponding to each amplifying unit and the power supply state to each amplifying unit based on the detection voltage obtained by the amplifying unit, Among the amplifying units, the number of amplifying units corresponding to the detecting voltage is turned on so that the corresponding switching unit is turned on and the input and output are short-circuited so that the amplification rate by the amplifying unit is lower as the detection voltage is larger. At the same time, the non-operating state is established in which the power supply is stopped.

  The invention described in claim 11 is a television receiving amplifying device for amplifying a television signal received by an antenna for receiving a television broadcast wave and transmitting the amplified signal to a terminal side. A signal attenuating means for attenuating the TV signal, an amplifying means comprising a plurality of amplifying sections for amplifying the TV signal attenuated by the signal attenuating means, and the TV signal amplified by the amplifying means on the output terminal side Based on the television signal branched by the output branching means so that the television signal amplified by the amplification means is at a predetermined level. And automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means.

  The automatic gain adjusting means includes a signal level detection unit for detecting the television signal branched by the output branching unit, a detection voltage obtained by the detection by the signal level detection unit, and a predetermined control reference An arithmetic unit that controls the attenuation amount of the signal attenuating means by outputting a control signal of a level corresponding to the detected voltage when the detected voltage is larger than the reference voltage for control. Become.

  Furthermore, provided for each of the amplifying units, a switching unit for short-circuiting the input and output of the amplifying unit, an input branching unit for branching a part of the television signal input to the input terminal, and the input Input detecting means for detecting the television signal branched by the branching means, the state of the switch means corresponding to each of the amplifying units based on the detection voltage obtained by the detection by the input detecting means, and An amplifying unit control means for controlling a power supply state to the amplifying unit, wherein the amplifying unit control means includes the amplifying unit among the amplifying units so that the amplification factor by the amplifying unit decreases as the detection voltage increases. The number of amplifying units corresponding to the detection voltage is set to a non-operating state in which the corresponding switch unit is turned on to short-circuit between input and output and power supply is stopped.

  According to the television reception amplifying device having each configuration described above, the amplification factor of the amplification unit is controlled in accordance with the input signal level. For example, the amplification factor of the amplification unit decreases as the input signal level increases (that is, the non-operating state). Increase the number of amplifiers). Therefore, the same operation and effect as the ninth aspect of the invention can be obtained.

  Next, a twelfth aspect of the present invention is the television reception amplifying device according to any one of the first to eleventh aspects, wherein the control reference voltage is a distortion factor of the amplification means for the television signal of a plurality of channels. Is set to a detection voltage value obtained by collectively detecting the television signal amplified by the amplifying means so that the signal level is within a predetermined standard range.

  According to the television reception amplifying apparatus having the above configuration, in various television signal situations such as fluctuations in input level when the number of channels is constant and fluctuations in combined power due to increase in the number of channels when the input level is constant. The attenuation amount of the signal attenuating means is controlled so that the distortion rate of the amplifier circuit falls within a predetermined standard range.

  Further, the control reference voltage may be variably set continuously or stepwise as described in claim 13 or claim 14, for example. That is, the invention described in claim 13 is the television receiving amplifying device according to any one of claims 1 to 12, wherein an output level of the television receiving amplifying device is set so that a distortion factor of the amplifying means is within a predetermined standard range. The control reference voltage setting means is provided which can set the control reference voltage continuously or stepwise so that it can be changed continuously or stepwise within the range.

  The invention according to claim 14 is the television receiving amplifying device according to any one of claims 1 to 12, wherein the television receiving amplifying device regardless of the increase or decrease in the number of channels of the television signal input to the television receiving amplifying device. The control reference voltage can be set continuously or stepwise so that the output level of the television receiving amplifying device can be kept constant within a range where the distortion factor of the amplifying means is within a predetermined standard range. Reference voltage setting means is provided.

  In the case of the former (Claim 13), it is possible to provide a convenient TV reception amplifying device that can select an output level that can easily optimize the terminal level according to, for example, the loss of a distributor or coaxial cable in the house. It becomes. In the latter case (Claim 14), the terminal level is easily optimized depending on the number of channels of television signals in the area where the amplification device is installed, taking into account the loss of distributors and coaxial cables in the house, for example. Therefore, it is possible to provide a TV reception amplifying apparatus that can be easily selected.

  By the way, as a specific detection method by the signal level detection unit, there is, for example, the above-described peak value detection, and the problem about this is as already described (saturation / distortion). On the other hand, there is a method for detecting the average value, which is disclosed in, for example, Japanese Patent Laid-Open No. 60-199208.

  Specifically, an AGC element, an amplifier circuit, and a demultiplexing circuit are connected in series between the input and output terminals, and the demultiplexing output of the demultiplexing circuit is converted into an AGC circuit composed of a detection circuit, a DC amplification circuit, and a comparison circuit. The AGC element is controlled by an input and an output (control signal) from the AGC circuit. Then, the DC signal level of the detection output (output from the DC amplification circuit) when the maximum output of the amplification circuit is detected by the detection circuit when the distortion rate of the amplification circuit is within a predetermined setting range is used as a reference in the comparison circuit. As a voltage, a multi-channel television signal input to the input terminal of the amplifying device is collectively detected by a detection circuit and amplified by a DC amplification circuit, and the reference voltage is compared by a comparison circuit. Is controlled and amplified with automatic gain adjustment.

  In the television co-amplifier described in the above publication, the detection result corresponding to the maximum output level satisfying the distortion rate standard of the amplifier circuit is used as the reference voltage. There is an effect that the distortion factor of the amplifier circuit can be kept within the standard, and the maximum gain is always obtained within the range satisfying the distortion factor standard of the amplifier circuit.

  However, this method of controlling the distortion rate to be within a certain standard for any input level caused fluctuations in the output level. That is, the detection circuit is composed of an average value detection circuit, and the AGC circuit is a composite signal level of a plurality of input signals when the input level varies due to variations in the input level or the number of reception channels. Is configured to control the AGC element so as to be within a range satisfying the distortion rate standard of the amplifier circuit. Since the television signal whose level is controlled by the AGC element is amplified by the amplifier circuit and output to the output terminal, the output level varies depending on the input level.

  Therefore, in the method in which the output level fluctuates like the method described above, there is a problem that the level calculation for drawing into the house cannot be performed, and it is possible to install without worrying about the input level. Although usefulness was recognized, there was a problem in practical use.

  Therefore, for example, as described in claim 15, it is conceivable to detect the television signal from the output branching means by a plurality of detection methods and to control the signal attenuating means based on each detection result.

  That is, the invention described in claim 15 is used for amplifying a television signal received by an antenna for receiving a television broadcast wave and transmitting the amplified signal to the terminal side. And amplifying the attenuated television signal by an amplifying means and outputting the amplified signal from an output terminal. One of the television signals amplified by the amplifying means is provided. An output branching unit for branching the unit, and an attenuation amount of the signal attenuating unit based on the television signal branched by the output branching unit so that the television signal amplified by the amplification unit has a predetermined level Automatic gain adjusting means.

  The automatic gain adjusting means includes a plurality of AGC circuits configured to control the attenuation amount of the signal attenuating means based on the detection voltage obtained by detecting the television signal branched by the output branching means. The AGC circuits are configured to perform the detection by different detection methods, and the attenuation amount of the signal attenuating means is controlled by the plurality of AGC circuits.

  According to the television reception amplifying apparatus having the above-described configuration, the attenuation amount is controlled by an appropriate method (controlling the gain of the amplifier circuit) with respect to fluctuation factors such as fluctuations in input signal level due to input signal level fluctuations and wave number increases. It is possible to provide an amplifying apparatus for television reception that can be used.

  According to a sixteenth aspect of the present invention, in the television reception amplifying device according to the fifteenth aspect, the AGC circuit includes an AGC circuit based on average value detection and an AGC circuit based on peak value detection.

  An AGC circuit based on average value detection includes an average value detection circuit for detecting an average value of a television signal branched by the output branching means, a distortion factor of the amplification means being within a predetermined standard range, and the amplification means. A detection voltage obtained by detecting the television signal when the amplified television signal is at a preset maximum level by the average value detection circuit is used as a control reference voltage, and the control reference voltage and the average value detection circuit are used. A comparison circuit for comparing the detection voltage and controlling the attenuation amount of the signal attenuation means according to the comparison result, and the AGC circuit based on the peak value detection is a peak of the television signal branched by the output branching means. A peak value detection circuit for detecting a value, and an output level adjustment circuit for controlling the attenuation amount of the signal attenuating means based on a detection voltage by the peak value detection circuit.

  The signal attenuating means includes a first attenuating means and a second attenuating means connected in series on the transmission path of the television signal, and the attenuation amount of the first attenuating means is controlled by the AGC circuit based on the average value. The second attenuating means is configured such that the amount of attenuation is controlled by the AGC circuit based on the peak value.

  According to the television reception amplifying apparatus having the above configuration, the AGC based on the peak value is performed until the output level reaches the reference voltage of the comparison circuit constituting the AGC circuit based on the average value detection, that is, in a range where the distortion does not exceed the standard. When the output level is kept constant by the circuit and the distortion rate exceeds the reference level, a television reception amplifying apparatus that lowers the output level so that the distortion rate becomes constant by the AGC circuit based on the average value detection can be provided.

  Thus, at the time of installation, it is not affected by the level of the input signal or the number of channels of the input signal, and even after the installation, even if there is a fluctuation in the level of the input signal or an increase in the number of channels of the input signal, it is not affected. Therefore, installation is easy even without specialized knowledge and measuring instruments.

  Here, it is more preferable to share a part of the circuits constituting the two AGC circuits, for example, as described in claim 17. That is, the invention according to claim 17 is the television reception amplifying device according to claim 16, wherein the average value detection circuit detects a television signal branched by the output branching means, and the detection An integration circuit for obtaining an average value of the television signal by integrating the detection signal by the detector, the peak value detection circuit comprising the detector constituting the average value detection circuit, and the detection signal by the detector And a smoothing circuit for smoothing. According to the television reception amplifying apparatus configured as described above, the apparatus can be reduced in size and cost.

  The invention according to claim 18 is the television receiving amplifying device according to claim 16 or 17, wherein the preset maximum level is output from the television receiving amplifying device to the terminal side. In consideration of the loss of the signal that occurs on the transmission path to the terminal side, the level of the television signal on the terminal side is set to a specified level.

  According to the television reception amplifying device having the above configuration, the output level of each amplifying device can be adjusted to a value obtained by modeling the loss of the distribution system of the reception system, for example (for example, 2 distribution system, 3 distribution system,...). Therefore, it has the convenience that it can be easily installed so that the terminal level is almost constant at the appropriate level.

  The invention according to claim 19 is the television receiving amplifying device according to claim 18, wherein the control reference voltage is set continuously or stepwise so that a plurality of types of the preset maximum levels can be set. It is configured so that it can be set to. With this configuration, for example, the output level can be adjusted so as to correspond to a value obtained by modeling the loss of the distribution system of the receiving system (for example, the 2-distribution system, the 3-distribution system,...). It can be installed so that the level is almost constant, and attachment is easy.

  Next, a twentieth aspect of the invention is the television reception amplifying device according to any one of the sixteenth to nineteenth aspects, wherein a direct current amplifier circuit is provided between the peak value detection circuit and the output level adjustment circuit. The DC amplifier circuit is configured such that the amplification degree changes according to the level of the television signal input from the input terminal. According to the television reception amplifying device having the above configuration, the fluctuation of the detection voltage of the peak value detection circuit due to the input level is reduced, and the level adjustment range by the output level adjustment circuit is almost constant even when the input level changes. It can be.

  Next, a twenty-first aspect of the present invention is the television reception amplifying device according to any one of the sixteenth to twentieth aspects, wherein the television to the television reception amplifying device is based on the output from the peak value detection circuit. A non-signal detecting means for detecting the presence / absence of a signal input, and a third attenuating means provided on a transmission path from the input terminal to the amplifying means, wherein the third attenuating means is the no-signal detecting means. The amount of attenuation is controlled in accordance with the detection result obtained by. According to the television reception amplifying device having the above configuration, for example, when there is no input signal, an effect of preventing the noise floor of the amplifying means from being increased can be obtained, and adverse effects on the system can be prevented.

Next, a twenty-second aspect of the present invention is the television receiving amplifying device according to any of the sixteenth to twenty-first aspects, wherein the amount of attenuation of the first attenuation means is controlled by the AGC circuit based on the average value. This is provided with a control switching means capable of selectively switching between the two. By providing the control switching means in this way, for example, if the attenuation control by the first attenuation means is not performed when there is a margin in the distortion rate, the output level is always constant by the AGC circuit based on peak value detection. It can be used to be in the state of
The invention according to claim 23 is the television receiving amplifying device according to any one of claims 16 to 22, wherein the fourth attenuation is provided on the transmission line from the output branching means to the output terminal. And an attenuation characteristic of the first attenuation means or the second attenuation means in accordance with an output from at least one of the AGC circuit based on the peak value detection or the AGC circuit based on the average value detection. Output adjusting means for controlling the attenuation amount of the fourth attenuating means. According to the television reception amplifying device configured as described above, a constant output level can be maintained even when a high input voltage is applied to the input terminal.

  A twenty-fourth aspect of the invention is the television receiving amplifying device according to any one of the sixteenth to twenty-third aspects, wherein the AGC circuit based on the average value has an input level to the comparison circuit for the control. Display means for displaying when the voltage becomes higher than the reference voltage is provided.

  According to the television reception amplifying apparatus having the above-described configuration, for example, the output level is lowered so that the first attenuation means is operating by an ACG circuit based on average value detection, that is, the distortion rate is constant. The installer can be informed that the condition is present. This display is also a warning for a drop in the output level, and can be used to indicate the possibility that the terminal level at the television terminal in the house is lower than the optimum level.

Preferred embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is an explanatory diagram showing a schematic configuration of the television receiving system of the present embodiment. A television receiving system 1 of the present embodiment is provided for viewing various television broadcasts in a building or a dwelling unit. As shown in FIG. 1, a VHF antenna 2 for receiving broadcast waves in the VHF band, and a UHF band UHF antenna 3 for receiving the broadcasting radio waves and BS antenna 4 for receiving the satellite broadcasting (BS) radio waves, and the received radio waves (hereinafter referred to as “TV signals”) from these antennas 2, 3, 4. Are transmitted to the television receiver amplifying apparatus 10 through coaxial cables 2a, 3a, and 4a, respectively.

  The television signals are combined and amplified in the amplification device 10, and the output is drawn into the house via the coaxial cable 5. A distributor 6 is connected to the coaxial cable 5, and four outputs from the amplifying apparatus 10 are distributed. One of the distributed outputs is connected to a VU / BS demultiplexer 9 via a coaxial cable 7 and a TV terminal 8. A TV receiver 9 a is connected to the VU side of the VU / BS demultiplexer 9. A BS tuner 9b is connected to the side.

  Next, the television reception amplifying apparatus 10 constituting the television reception system 1 of the present embodiment will be described with reference to FIG. The television receiving amplifying apparatus 10 is configured such that a changeover switch 14, an amplifier circuit 15, and a branch circuit 16 are connected in series between an input terminal 11 and an output terminal 12. A pass line 19 and a high frequency signal attenuator 21 are connected to the changeover switch 14. Therefore, an installer, a user, or the like operates the changeover switch 14 to transmit the television signal input from the input terminal 11 as it is through the passage line 19 to the amplification circuit 15 side or to attenuate the high frequency signal. Whether the signal is attenuated by the device 21 and sent to the amplifier circuit 15 can be freely switched.

  The attenuation amount of the high-frequency signal attenuator 21 is controlled by a control signal from the automatic gain adjustment unit 20. The automatic gain adjustment unit 20 generates a control signal to the high frequency signal attenuator 21 based on the branch output from the branch circuit 16, and includes a filter 26, a detection unit 30, a calculation unit 40, a reference voltage, and the like. And a circuit 50.

  The filter 26 is connected to the branch output terminal 16a of the branch circuit 16, and is a frequency band of a signal to be amplified by the amplifier circuit 15 (that is, a frequency band of each television signal of UHF, VHF, BS input to the input terminal 11). Pass a signal in the same frequency band as. The filter 26 may be configured by, for example, a band-pass filter, or may be configured by combining a high-pass filter and a low-pass filter, and the specific configuration (type) is not limited. This filter 26 can prevent the AGC function (automatic gain adjustment function), which is the main function of the automatic gain adjustment unit 20, from malfunctioning due to interference radio waves (for example, radio waves from a mobile phone) generated outside the passband. . However, this filter 26 may not be used when it is not particularly necessary, such as when it is not necessary to consider the influence of jamming radio waves.

  The detection unit 30 receives the branch output signal output from the filter 26 and detects the intensity of the output level of the television receiving amplifying apparatus 10. Specifically, the detection unit 30 can be configured by, for example, a detection circuit using a signal detection diode and a smoothing circuit configured by a capacitor, a resistor, and the like, details of which will be described later.

  The calculation unit 40 takes in the detection value (detection voltage) output from the detection unit 30 and compares it with the reference value (reference voltage Vref), so that the output level from the television receiving amplifying device 10 is a predetermined reference level. For example, an arithmetic circuit composed of an operational amplifier and a resistor is provided.

  The reference voltage circuit 50 generates a reference voltage Vref that serves as a reference for comparison / determination in the arithmetic unit 40. The reference voltage circuit 50 divides the power supply voltage Vcc by a resistance ratio based on a combination of a resistor and a variable resistor to obtain a desired voltage. The reference voltage Vref can be generated.

  In the television receiving amplifying apparatus 10 configured as described above, the intensity of the output level from the amplifying apparatus 10 is detected by the detection unit 30, and the detection voltage that is the detection result does not exceed the reference voltage Vref. The calculation unit 40 makes such a determination. When the detection voltage is higher than the reference voltage Vref, a control signal corresponding to the detection voltage is output from the calculation unit 40, and the high-frequency signal attenuator 21 is controlled by this control signal. Therefore, when the changeover switch 14 is switched to the high frequency signal attenuator 21 side, the amplifying apparatus 10 amplifies the input signal (television signal) while automatically performing gain adjustment. That is, the automatic gain adjustment function is activated.

  On the other hand, when the detection voltage is lower than the reference voltage Vref, the control signal output from the calculation unit 40 becomes almost zero, no control voltage is applied to the high-frequency signal attenuator 21, and the high-frequency signal attenuator 21 has an attenuation amount. The passing state is almost zero. Therefore, the amplifying apparatus 10 is in a state where the automatic gain adjustment function does not operate even when the changeover switch 14 is switched to the high frequency signal attenuator 21 side (almost the state where the changeover switch 14 is switched to the pass line 19 side). Equivalent state).

  That is, the television receiving amplifying device 10 operates as an amplifying device having no automatic gain adjustment function when the changeover switch 14 is switched to the passing line 19 side, and when the changeover switch 14 is switched to the high frequency signal attenuator 21 side. Operates to amplify while performing automatic gain adjustment as described above. In the following description, it is assumed that the changeover switch 14 is switched to the high frequency signal attenuator 21 side unless otherwise specified.

  Next, specific internal configurations (circuits) of the automatic gain adjusting unit 20 and the high-frequency signal attenuator 21 constituting the television receiving amplifying device 10 will be described with reference to FIG. FIG. 3 is a circuit diagram showing a schematic configuration of the television receiving amplifying apparatus 10. In this figure, an input filter 13 is provided between the input terminal 11 and the changeover switch 14, and an output filter 17 and a power supply separation filter 18 are provided between the branch circuit 16 and the output terminal 12. However, these are not shown in FIG.

  A television signal input from the input terminal 11, for example, a signal in the UHF band (470 to 770 MHz) here passes through the input filter 13 having the UHF band as a pass band. On the output side of the input filter 13, there is provided a changeover switch 14 for selecting either the pass line 19 or the high-frequency signal attenuator 21, and the television signal from the input filter 13 is selected by this changeover switch 14. The signal is output from the output terminal 12 via either the pass line 19 or the high-frequency signal attenuator 21, the amplifier circuit 15, the branch circuit 16, the output filter 17 having the UHF band as the pass band, and the power supply separation filter 18.

  In the present embodiment, the power supply for operation of the television receiving amplifying apparatus 10 is configured to be supplied from the outside of the amplifying apparatus 10 via the output terminal 12. That is, the power supply voltage Vcc superimposed on the coaxial cable 5 (see FIG. 1) connected to the output terminal 12 is passed through the power supply separation filter 18 to the high-frequency signal attenuator 21, the amplifier circuit 15, the detection unit 30, and the calculation unit 40. The reference voltage circuit 50 is supplied.

  The detection unit 30 includes a detection unit including diodes D5 and D6, resistors R2 and R3, and a capacitor C5, and a smoothing circuit including a capacitor C4 and a resistor R4. A high-frequency television signal input from the branch output terminal 16a through the filter 26 is detected by the diodes D5 and D6 and then output to the arithmetic unit 40 as a DC voltage flattened by a smoothing circuit. The resistors R2 and R3 divide the power supply voltage Vcc to apply a bias voltage to the detection diodes D5 and D6, and detection is performed at a portion where the detection characteristics (IF-VF characteristics) of the diodes D5 and D6 have good linearity. It is for doing so.

  In the present embodiment, an example in which the bias voltage for improving the detection characteristic is set to a constant value based on the voltage dividing ratio of the resistors R2 and R3 has been described. However, for example, the bias voltage can be arbitrarily set using a variable resistor or the like. Needless to say, the bias voltage generation method is not limited to that shown in FIG. 3.

  The arithmetic unit 40 is configured as a so-called differential amplifier circuit including an operational amplifier OP1 and resistors R5, R6, R7, and R8 connected to the operational amplifier OP1. The detection voltage from the detection unit 30 is input to the non-inverting input terminal (+) of the operational amplifier OP1, and the reference voltage Vref is input from the reference voltage circuit 50 to the inverting input terminal (−). Then, a signal corresponding to the difference between the detected voltage and the reference voltage Vref is output to the high frequency signal attenuator 21 as a control signal.

  The reference voltage circuit 50 includes resistors R9 and R10 and a variable resistor VR1, and a potential obtained by dividing the power supply voltage Vcc by these resistors is input to the inverting input terminal of the operational amplifier OP1 as the reference voltage Vref. . That is, in this embodiment, the reference voltage Vref can be set to an arbitrary value by operating the variable resistor VR1. As the configuration of the reference voltage circuit 50, the reference voltage Vref may be continuously changed as in this example, or may be divided into a plurality of types in a stepped manner as in a reference voltage circuit 51 in FIG. The specific configuration is not limited as long as the desired reference voltage Vref can be generated.

  The control signal output from the arithmetic unit 40 is input to the high-frequency signal attenuator 21 via the choke coil L2, and the attenuation amount of the high-frequency signal attenuator 21 is controlled according to this control signal. The high frequency signal attenuator 21 includes diodes D1, D2, D3, D4, a resistor R1, a coil L1, capacitors C1, C2, C3, and the like. The choke coil L3 is a coil for applying a bias voltage to the diode from the power supply voltage. The choke coil L3 and the choke coil L2 are not shown in FIG.

  In the high-frequency signal attenuator 21 configured as described above, when the detection voltage from the detection unit 30 is equal to or lower than the reference voltage Vref, the output from the operational amplifier OP1 becomes a negative level. That is, the cathode side of the diode D2 becomes a negative level. Therefore, in this case, the attenuation amount of the high-frequency signal attenuator 21 is almost zero, and the television signal from the input terminal 11 is output to the amplifier circuit 15 side with almost no loss. On the other hand, when the detection voltage becomes larger than the reference voltage Vref, the potential on the cathode side of the diode D2 increases, and the attenuation amount of the high-frequency signal attenuator 21 increases. That is, the high-frequency signal attenuator 21 of the present embodiment is configured such that when the detection voltage is greater than the reference voltage ref, the attenuation is controlled based on the control signal at a level corresponding to the magnitude. .

  Here, how to determine the reference voltage Vref in the present embodiment will be described. In the present embodiment, when a television signal is input to the television receiving amplifying apparatus 10 and a predetermined level of the television signal in which the distortion factor of the amplifier circuit 15 is within the standard range is output from the amplifier circuit 15, A detection voltage obtained by detecting the output television signal in the detection unit 30 is set to the reference voltage Vref in the reference voltage circuit 50. Specifically, assuming that two waves are input to the input terminal 11 and the output level from the amplifier 10 when the distortion (intermodulation distortion; IM3) is 52 dB is 111 dBμ, The reference voltage Vref is set so as to be the same voltage as the detection voltage.

  In other words, when the output level of the amplifying device 10 increases due to vertical fluctuation of the input signal (television signal) level and exceeds 111 dBμ, the amplifying device 10 generates harmonics and distortions and generates a predetermined standard. It is conceivable that the television receiver 9a (see FIG. 1) cannot receive television broadcasts normally because the range is exceeded. Therefore, when the output level exceeds the set value (111 dBμ), the high frequency signal attenuator 21 is activated by the control signal from the calculation unit 40 and the input signal is attenuated. This control signal is output corresponding to the magnitude of the output level, the input signal level is appropriately attenuated by controlling the high frequency signal attenuator 21, and the output level is a specified value, that is, the distortion rate is specified in this example. The automatic gain adjustment is performed so that the intermodulation distortion as a value becomes an output level of 111 dBμ at which 52 dB is obtained.

  Further, the television receiving amplifying apparatus 10 of the present embodiment can cope with an increase in combined power due to an increase in the wave number of the received television signal. That is, in recent years, not only conventional analog broadcasting but also terrestrial digital broadcasting is newly started in the UHF band, and the low frequency band of the UHF band is used for this terrestrial digital broadcasting wave. For this reason, analog frequency change measures (ana-ana conversion) have been implemented to change analog broadcasts that previously used this frequency band to frequency bands that do not overlap with terrestrial digital broadcasts, and simultaneous broadcasts between terrestrial digital broadcasts and analog broadcasts. Is supposed to be done. This simulcast increases the number of channels in the UHF band, which may increase the combined power of the TV signal input to the TV reception amplifying apparatus 10.

  In the automatic gain adjusting unit 20 constituting the television receiving amplifying device 10, all television signals of channels in a desired band (for example, UHF band) are sent from the branch output terminal 16 a of the branch circuit 16 to the detection unit 30 via the filter 26. Entered. Then, the detection unit 30 detects the combined power within the necessary band, and based on this detection voltage, the distortion rate of the amplifier circuit 15 is within a predetermined range (in this application, intermodulation distortion; IM3 = 52 dB). Since the reference voltage Vref of the reference voltage circuit 50 is set, the automatic gain adjustment function operates even when the combined power increases due to an increase in wave number.

  According to the television receiver system 1 of the present embodiment described above, the changeover switch 14 can selectively switch between the pass line 19 and the high-frequency signal attenuator 21, so that the television signal is strong or the wave number is high. When the area is such that the combined power increases, the changeover switch 14 is switched to the high frequency signal attenuator 21 side so that the distortion rate falls within a predetermined standard range with respect to fluctuations in the input level. The automatic gain adjuster 20 operates so as not to exceed. Therefore, the television receiving amplifying apparatus 10 can be easily attached without any setting mistakes or operation mistakes.

  In addition, the reference voltage Vref in the present embodiment is the detection unit 30 that detects the television signal that is output when a predetermined level of the television signal in which the distortion rate of the amplifier circuit 15 is within the standard range is output from the amplifier circuit 15. The detected voltage is set. Therefore, even if this amplification device 10 is installed in an area where an increase in the combined power due to an increase in the number of channels is expected in the future, the automatic gain adjustment unit 20 appropriately adjusts the gain in response to the increase in the combined power. Therefore, it is not necessary to make a complicated adjustment by manual work again, and the television receiving amplifying apparatus 10 with high convenience can be provided.

  Further, when the television receiving amplification device 10 is used in a weak electric field region, if the changeover switch 14 is switched to the passing line 19 side, the television signal is directly input to the amplification circuit 15 without passing through the high frequency signal attenuator 21. Is done. In this case, it is possible to provide a highly versatile television receiving amplifying apparatus 10 that can be used as a low-noise amplifying apparatus with little passage loss.

  Furthermore, the reference voltage circuit 50 is configured so that the reference voltage Vref can be continuously variably set by operating the variable resistor VR1. Therefore, the reference voltage Vref can be selected in accordance with the number of TV signal channels in the area where the amplifier 10 is installed so that the terminal level is optimized in consideration of the loss of the distributor and the coaxial cable in the house. Therefore, it is possible to provide a convenient television receiving amplifying device.

  In the present embodiment, as a specific configuration example of the amplifier circuit 15, the example of the three-stage cascade connection of the first amplifier A1, the second amplifier A2, and the third amplifier A3 is shown. The number of stages may be increased or decreased. Further, for example, a manual gain adjustment circuit may be provided between the amplifiers. Further, when the changeover switch 14 is switched to the passing line 19 side and used as a low noise amplification device, supply of power supply voltage to each part of the automatic gain adjustment unit 20 and the high frequency signal attenuator 21 so that the automatic gain adjustment function does not operate. May be stopped. Further, the filter 26 between the branch output terminal 16a and the detection unit 30 may be omitted, and whether or not to be provided may be determined as appropriate. The same applies to each embodiment described later.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. In the present embodiment, the high frequency signal attenuator 21 corresponds to the signal attenuating means of the present invention (Claim 1), the amplifier circuit 15 corresponds to the amplifying means of the present invention, and the branch circuit 16 corresponds to the output branch means of the present invention. The automatic gain adjustment unit 20 corresponds to the automatic gain adjustment unit of the present invention, the detection unit 30 corresponds to the signal level detection unit of the present invention, the changeover switch 14 corresponds to the transmission path switching unit of the present invention, The reference voltage Vref corresponds to the control reference voltage of the present invention, and the reference voltage circuit 50 corresponds to the control reference voltage setting means of the present invention.

[Second Embodiment]
The television receiving amplifying apparatus 101 of the present embodiment shown in FIG. 4 is used in place of the television receiving amplifying apparatus 10 in the television receiving system 1 described in the first embodiment, and is described in the first embodiment. The television receiver amplifying apparatus 10 is provided with a high-frequency signal attenuator 21 between the input terminal 11 and the amplifier circuit 15, and a changeover switch 19 is interposed between the high-frequency signal attenuator 21 and the arithmetic unit 40. This is different from the above and the point that a manual control unit 61 capable of controlling the attenuation amount of the high-frequency signal attenuator 21 by a manual operation is provided. The rest of the configuration is basically the same. For this reason, the same components as those in the television receiving amplifying apparatus 10 (FIG. 2) of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A passage line 19 and a manual control unit 61 are connected to the changeover switch 14 so that they can be freely switched. If the changeover switch 14 is switched to the passage line 19 side, the arithmetic unit 40 and the high frequency signal attenuator 21 are connected. Therefore, in the amplification device 101, the changeover switch 14 is replaced with the high frequency signal attenuator in the first embodiment. As in the case of switching to the 21 side, the television signal is amplified while performing automatic gain adjustment based on the control signal from the automatic gain adjustment unit 20.

  For example, the manual control unit 61 can be configured to output the power supply voltage Vcc by controlling the voltage ratio by a combination of a resistor and a variable resistor. When the changeover switch 14 is switched to the manual control unit 61 side, the high-frequency signal attenuator 21 is connected to the manual control unit 61. Therefore, the high-frequency signal attenuation is achieved by changing the control signal (voltage) from the manual control unit 61. It is possible to manually control the attenuation of the device 21.

  According to the television reception amplifying apparatus 101 having the above configuration, when the changeover switch 14 is switched to the automatic gain adjustment unit 20 side, the changeover switch 14 is replaced with a high frequency signal attenuator in the television reception amplification apparatus 10 of the first embodiment. The same operation and effect as when switched to the 21 side can be obtained. In addition, in this embodiment, the attenuation amount of the high-frequency signal attenuator 21 can be manually set by switching the changeover switch 14 to the manual control unit 61 side.

  For this reason, it is easy to install such that installation location is not selected and complicated gain adjustment is not required for installation, and more convenient installation conditions can be selected depending on the location of the installation work and the installer. It is possible to provide a TV reception amplifying device with high performance.

Here, in the present embodiment, the manual control unit 61 corresponds to the manual gain adjusting means of the present invention, and the changeover switch 14 corresponds to the adjusting method switching means of the present invention.
[Third Embodiment]
The television receiving amplifying apparatus 102 of the present embodiment shown in FIG. 5 is also used in place of the television receiving amplifying apparatus 10 in the television receiving system 1 described in the first embodiment. The level display circuit composed of the first comparison unit 32 and the first display unit 33 and the level display circuit composed of the second comparison unit 42 and the second display unit 43 are provided for the television receiving amplification device 10 of FIG. The difference is that the reference voltage circuit 51 capable of switching the reference voltage Vref in a plurality of stages is provided, and the other configuration is basically the same. For this reason, the same components as those in the television receiving amplifying apparatus 10 (FIG. 2) of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first comparison unit 32, a detection voltage from the detection unit 30 when the output level of the amplifier circuit 15 is a predetermined level is set as a first reference voltage for comparison. In the first comparison unit 32, It is determined whether or not the detection voltage from the detection unit 30 is greater than the first reference voltage for comparison. Then, the first comparison unit 32 is configured to display the first display unit 33 based on the determination result.

  The first reference voltage for comparison is, for example, a detection voltage from the detection unit 30 when the strength of the television signal is a weak electric field area or a level that is not so strong that the output of the amplifying apparatus 102 is not likely to be distorted. Determine based on That is, when the amplification device 102 is installed, if it is determined that the detection voltage from the detection unit 30 is lower than the first reference voltage for comparison, the first display unit 33 is displayed.

  By displaying the first display unit 33 in this manner, the user can confirm that the intensity state of the television signal at the installation location is a weak electric field, or that the distortion level is within a predetermined range and the output level has a sufficient margin. Can be seen at a glance. Therefore, when the display by the first display unit 33 is made, the user can use the amplifying device 102 as a low noise amplifying device by switching the changeover switch 14 to the passing line 19 side, and reception with better C / N is possible. become able to.

  Conversely, when the first display unit 33 is not displayed, it can be seen at a glance that the TV signal level is strong, and the changeover switch 14 may be switched to the high frequency signal attenuator 21 side. Thereby, the attenuation amount of the high frequency signal attenuator 21 is controlled by the automatic gain adjustment unit 63 so that the occurrence of distortion falls within the standard range. That is, in this case, it is used as an amplifying device having an automatic gain adjustment function. The first comparison unit 32 may be configured using, for example, an operational amplifier, and the first display unit 33 may be a light emitting diode, for example.

  Next, the second comparison unit 42 and the second display unit 43 will be described. In the second comparison unit 42, the output voltage (control signal) of the calculation unit 40 when the distortion rate of the amplifier circuit 15 is within a predetermined standard range and the output level is the maximum set output level is used for comparison. The second reference voltage is set, and the second comparison unit 42 determines whether or not the output voltage of the calculation unit 40 is larger than the comparison second reference voltage. And the 2nd comparison part 42 is comprised so that the 2nd display part 43 may be displayed based on the determination result.

  For example, the second reference voltage for comparison is determined based on a control signal from the calculation unit 40 when the distortion factor of the amplifier circuit 15 exceeds a predetermined range. In the present embodiment, for example, based on a standard generally referred to as a distortion factor reference of an amplifying apparatus in the UHF band, “intermodulation distortion (IM3) is 52 dB at an output level of 111 dBμ at two-wave input”. This is based on the control signal when the rate exceeds 52 dB.

  That is, if the second comparison unit 42 determines that the control signal is greater than the second reference voltage for comparison, the second display unit 43 is displayed assuming that the distortion rate exceeds the standard. By displaying the second display unit 43 in this manner, the user can easily understand that the distortion rate of the television receiving amplifying device 102 exceeds the standard range due to excessive input at the installation location. In that case, for example, a fixed attenuator may be provided between the input terminal 11 and the changeover switch 14 for quick measures. This is embodied in the fourth embodiment (see FIG. 6), details of which will be described later.

  The second comparison unit 42 may be configured by using an operational amplifier, and the second display unit 43 may be a light emitting diode or the like. Further, in this example, the case where the display is performed when the distortion rate exceeds a predetermined range is given as an example. However, the display is not limited to this. For example, the display is performed when the distortion rate exceeds a predetermined distortion rate within a standard range. The second reference voltage for comparison may be set as appropriate.

  Next, the reference voltage circuit 51 of the present embodiment is configured such that a plurality of types of reference voltages Vref used by the arithmetic unit 40 can be set stepwise. Specifically, the power supply voltage Vcc is divided by resistors R9, R10, and R11, and the reference voltage Vref is set to a plurality of types by switching these divided values using a switch or the like (details are not shown). I can do it. In this configuration, for example, when the output level shows the maximum when the distortion is within a predetermined standard range, that is, the output level is variable (decreased) in 3 dB steps, for example, based on the detection voltage at the maximum output level. Can be set). More specifically, the output level can be sequentially changed to 111, 108, 105, 102, and 99 dBμ.

  Here, a description will be given of merits when a plurality of types of reference voltages Vref can be set as in this example. For example, when the number of channels of the TV signal input to the amplifying apparatus 102 differs depending on the place where the amplifying apparatus 102 is installed (for example, there are areas where two-wave signals are received, but seven-wave signals are received) Depending on the region and the TV signal distribution system, the terminal level at the TV terminal in the house may be optimal or too large as necessary.

  As a specific example, when the amplifying apparatus 102 is set so that the output level is 103 dBμ and the distortion is 52 dB with 7 waves, the amplifying apparatus 102 is used in an area where a two-wave signal is received. The automatic gain adjustment function is activated and the output level is increased. Then, as described above, even if the number of distributions in the house, the wiring of the coaxial cable, and the like are taken into account, the level at the terminal becomes too large, and there is a possibility that the television receiver or the like becomes an excessive input.

  Therefore, in the present embodiment, the reference voltage circuit 51 is configured so that a plurality of types of reference voltages Vref can be set as described above, and, for example, seven waves are provided corresponding to the number of channels of the television signal input to the amplifier 102. In this case, the output level can be made constant regardless of the number of channels, such as 103 dBμ (distortion rate is 52 dB of the standard value) and 103 dBμ even in the case of two waves.

  Therefore, according to the television reception amplifying apparatus 102 having the above configuration, the same effects as those of the television reception amplifying apparatus 10 (FIG. 2) of the first embodiment can be obtained, and the first comparison unit 32 and the first display Since the level display circuit including the unit 33 is provided, the state of the input strength of the television signal can be determined at a glance when the amplification device 102 is installed. Based on the display on the first display unit 33, the changeover switch 14 can be determined. Depending on the situation, it is appropriate to switch to the side of the passage path 19, that is, to be used as a low noise amplifying device, or to switch the selector switch 14 to the high frequency signal attenuator 21 side and perform amplification while applying automatic gain adjustment. Can be selected. Therefore, it is possible to provide a TV reception amplifying device that can be easily installed without selecting an installation place or an installer, and that is easy to install.

  In addition to the level display circuit, a level display circuit comprising the second comparison unit 42 and the second display unit is also provided, so that the output signal level is such that the distortion rate of the amplifier circuit 15 exceeds a predetermined standard range. It is possible to provide an amplifying apparatus for television reception capable of notifying at a glance and capable of quickly taking appropriate measures against an increase in input level.

  In addition, since the reference voltage circuit 51 is configured so that the reference voltage Vref can be switched in a stepwise manner, high frequency loss due to the number of distributions in the house, lead-in lines, etc. is taken into account at the site where the television receiving amplifier 102 is used. Thus, it is possible to easily optimize the terminal level of the TV terminal, and to provide a highly compatible TV receiving amplifying apparatus 102.

  Here, in the present embodiment, the first comparison unit 32 corresponds to the first comparison unit of the present invention, the first display unit 33 corresponds to the first display unit of the present invention, and the second comparison unit 42 corresponds to the present invention. The second display unit 43 corresponds to the second display means of the present invention, and the reference voltage circuit 51 corresponds to the control reference voltage setting means of the present invention.

[Fourth Embodiment]
In the third embodiment, the level display circuit including the second comparison unit 42 and the second display unit 43 allows the user to set the amplification device 102 at an installation location of the amplification device 102 so that the distortion exceeds the standard range due to excessive input. We were able to easily recognize that it was in the state. Therefore, as described above, in order to lower the input level, for example, a fixed attenuator can be quickly provided between the input terminal 11 and the changeover switch 14. The television reception amplifying apparatus of the present embodiment is embodied so that this “measure such as providing a fixed attenuator” can be easily performed, and the configuration thereof is shown in FIG.

  The television reception amplifying apparatus 105 of the present embodiment shown in FIG. 6 is mainly composed of an input level adjusting unit 66 and an AGC amplifying unit 101a. Among them, the AGC amplification unit 101a removes the changeover switch 19 and the manual control unit 61 from the television reception amplification device 101 (see FIG. 4) of the second embodiment and directly outputs the control signal from the automatic gain adjustment unit 20 to the high frequency. A level display circuit composed of a second comparison unit 42 and a second display unit 43 that constitute the input to the signal attenuator 21 and constitute the television receiving amplifying device 102 (see FIG. 5) of the third embodiment. Similarly, the configuration is provided on the output side of the calculation unit 40. Therefore, for each component of the AGC amplification unit 101a, the same component as in FIG. 4 or FIG. 5 is given the same reference numeral, and detailed description of the AGC amplification unit 101a is omitted.

  The input level adjustment unit 66 includes a changeover switch 73 provided between the input terminal 11 and the AGC amplification unit 101a in the television reception amplification device 105, and an input signal (television signal) from the input terminal 11 as it is. A pass line 75 for passing the signal to 101a and an input attenuator 71 for attenuating the input signal from the input terminal 11 and outputting it to the AGC amplifier 101a.

  The changeover switch 73 selectively switches either the passage line 75 or the input attenuator 71. Therefore, the input signal is output to the AGC amplifying unit 101a via either the pass line 75 or the input attenuator 71 selected by the changeover switch 73. The input attenuator 71 is configured as a fixed value whose attenuation is set in advance.

  In the television reception amplifying device 105 of the present embodiment configured as described above, for example, when the installation is performed by switching the changeover switch 73 to the passing line 75 side, and the installation location is a weak electric field region, Since the second display unit 43 does not display, the changeover switch 43 may be left as it is. On the other hand, for example, when the second display unit 43 is displayed when it is installed in a strong electric field area such as the vicinity of a transmission tower that transmits broadcast radio waves, the changeover switch 73 is switched to the input attenuator 71 side. The input level can be lowered so that the distortion factor of the amplifier circuit 15 falls within the standard range.

  Therefore, according to the television reception amplifying apparatus 105 having the above configuration, the input level adjusting unit 66 is provided in the preceding stage of the AGC amplifying unit 101a so that it is possible to select whether or not the input signal is attenuated by the input attenuator 71. Compared with the configuration of only the AGC amplifier 101a, the dynamic range of the input signal is widened, and the same amplifying device 105 is provided in the vicinity of the transmission tower where the electric field strength is high or in the weak electric field area far from the transmission tower. Can be used.

Here, in this embodiment, the input attenuator 71 corresponds to the input attenuating means of the present invention, and the changeover switch 73 corresponds to the input side path switching means of the present invention.
[Fifth Embodiment]
The television reception amplifying device 106 of this embodiment shown in FIG. 7 is also configured by an input level adjusting unit 67 for adjusting the level by appropriately attenuating the input level, and an AGC amplifying unit 103. Among these, the AGC amplification unit 103 has the same configuration as the television reception amplification device 102 of the third embodiment shown in FIG. Further, in the input level adjustment unit 67, the input level adjustment unit 66 that constitutes the television reception amplifying device 105 (FIG. 6) of the switch 73, the passage line 75, and the input attenuator 71 is provided. Is exactly the same. Therefore, the same components as those of the television reception amplifying devices 102 and 105 of the third and fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, the input level adjusting unit 67 will be mainly described.

  In the present embodiment, the switching operation of the selector switch 73 in the input level adjustment unit 67 is not automatically performed by a user or the like, but is automatically performed according to the input signal level. That is, a part of the television signal input from the input terminal 11 is branched by the branch circuit 77 and output from the branch output terminal 77a. The branched television signal is detected by the input detection circuit 78, and the detection voltage is compared with the input reference voltage Vrin in the comparison circuit 79.

  The input detection circuit 78 can be configured, for example, in the same manner as the detection unit 30 (see FIG. 3) described in the first embodiment. However, as long as a detection voltage corresponding to the input signal level can be obtained, various configurations are adopted. sell. The comparison circuit 79 can be configured with, for example, a comparator as a main element, and outputs a signal to that effect to the changeover switch 73 when the detection voltage becomes equal to or higher than the input reference voltage Vrin. Specifically, for example, when the detection voltage is lower than the input reference voltage Vrin, the signal from the comparison circuit 79 to the changeover switch 73 is at the low level, and when the detection voltage is equal to or higher than the input reference voltage Vrin, the signal is at the high level.

  The changeover switch 73 switches to the passing line 19 side while the signal from the comparison circuit 79 is at the low level, and switches to the input attenuator 71 side while the signal from the comparison circuit 79 is at the high level.

  That is, in the input level adjustment unit 67, when the input level is low, the changeover switch 73 is switched to the passing line 75 side so that the input signal is input to the AGC amplification unit 103 without being attenuated. When the detection voltage from the detection circuit 78 becomes larger than the input reference voltage Vrin, the changeover switch 73 is switched to the input attenuator 71 side to attenuate the input signal by a predetermined attenuation amount (fixed value), and the AGC amplification unit 103 is input.

  Therefore, according to the television receiving amplifying device 106 of the present embodiment, the dynamic range of the input signal is expanded, and the same amplifying device 106 can be used in both the strong electric field region and the weak electric field region. In addition to obtaining the same effect as the television reception amplifying device 105 of the embodiment, the switching operation of the changeover switch 73 is automatically performed according to the input signal level, so that a more convenient amplifying device is provided. Is possible.

  Here, in the present embodiment, the branch circuit 77 corresponds to the input branch means of the present invention, the input detection circuit 78 corresponds to the input detection means of the present invention, and the comparison circuit 79 corresponds to the input comparison means of the present invention. .

[Sixth Embodiment]
In the television reception amplifying apparatus 106 (FIG. 7) of the fifth embodiment, the attenuation level of the input attenuator 71 in the input level adjustment unit 67 is fixed, and the input signal is attenuated by the attenuation level. Only one of the passage lines 75 can be selected without being attenuated. On the other hand, the television reception amplifying apparatus 107 of the present embodiment shown in FIG. 8 is configured such that the input level adjustment unit 68 can continuously change the attenuation of the input signal according to the input level.

  That is, as shown in FIG. 8, the comparison circuit 79a constituting the input level adjustment unit 68 is different from the comparison circuit 79 in the fifth embodiment (FIG. 7) according to the magnitude of the detection voltage from the input detection circuit 78. The changing control signal is output to the input attenuator 72. The input attenuator 72 is configured such that the amount of attenuation changes according to the control signal from the comparison circuit 79a.

  Specifically, based on the difference between the detection voltage and the input reference voltage Vrin, the attenuation amount of the input attenuator 72 is decreased as the detection voltage is smaller, and conversely, the trick amount of the input attenuator 72 is increased as the detection voltage is increased. Will increase. That is, the attenuation amount of the input attenuator 72 is changed continuously (or stepwise) in accordance with the input signal level, and finer level adjustment is possible compared to the fifth embodiment. .

  Note that the AGC amplification unit 101b that amplifies the input signal attenuated by the input attenuator 72 is the same as the second comparison unit 42 and the second display from the AGC amplification unit 101a that constitutes the television receiving amplification device 105 of the fourth embodiment. The level display circuit composed of the unit 43 is removed, and the basic operation of adjusting the gain is exactly the same as that of the AGC amplification unit 101a. In the present embodiment, the input attenuator 72 corresponds to the input attenuating means of the present invention (claim 9).

[Seventh Embodiment]
The television reception amplifying apparatus 108 of this embodiment shown in FIG. 9 does not attenuate the input signal based on the level of the input signal as in the fourth to seventh embodiments, but based on the input signal level. Whether to use each of the first amplifier A1, the second amplifier A2, and the third amplifier A3 constituting the amplifier circuit 15 is controlled.

  That is, in the signal transmission path from the input terminal 11 to the output terminal 12, the first switch 81 is connected in parallel with the first amplifier A1, the second switch 82 is connected in parallel with the second amplifier A2, and the third amplifier A3. And a third switch 83 is connected in parallel. Each of these switches 81, 82, 83 is individually controlled by the input side gain adjustment unit 69 (specifically, by a signal from the comparison / control unit 80). The comparison / control unit 80 also supplies power to the amplifiers A1, A2, and A3.

  The comparison / control unit 80 controls the state of each switch 81, 82, 83 and the power supply state to each amplifier A1, A2, A3 according to the detection voltage from the input detection circuit 78. Specifically, for example, while the detection voltage is lower than the input reference voltage Vrin, the input signal level is low. Therefore, all the switches 81, 82, 83 are turned off and power is supplied to all the amplifiers A1, A2, A3. Do. Thereby, the television signal input via the high frequency signal attenuator 21 is sequentially amplified by each amplifier A1, A2, A3.

  On the other hand, when the input level becomes high and the detection voltage becomes equal to or higher than the input reference voltage Vrin, the comparison / control unit 80 stops, for example, power supply to the first amplifier A1 and turns on only the first switch 81. That is, in this case, the television signal from the high frequency signal attenuator 21 passes through the first switch 81 and is amplified by the second amplifier A2 and the third amplifier A3.

  In addition, for example, two different input reference voltages Vrin1, Vrin2 (Vrin1 <Vrin2) are set, and when the detection voltage is smaller than any input reference voltage, all the switches are turned off and all the amplifiers A1, A2, A3 are all turned on. When the detection voltage is equal to or higher than the first input reference voltage Vrin1 and smaller than the second input reference voltage Vrin2, only the first switch 81 is turned on to stop the power supply to the first amplifier A1, and the detection is performed. When the voltage is higher than any input reference voltage, the first and second switches 81 and 82 may be turned on and the power supply to the first and second amplifiers A1 and A2 may be stopped.

  Further, even when there are two or four or more amplifiers constituting the amplifier circuit 15, switches are connected in parallel to the respective amplifiers, and switch switching and amplifiers based on the input signal level are performed in the same manner as described above. It is also possible to perform power supply control to the. For example, a fourth amplifier (not shown) is provided after the third amplifier A3, and a fourth switch (not shown) is connected in parallel with the fourth amplifier so that power supply to the fourth amplifier and operation of the fourth switch can be performed. You may make it control from the comparison / control part 80. FIG.

  That is, the number of combinations of amplifiers and switches connected in parallel thereto is not limited to three as in the present embodiment, and a plurality of types of input reference voltages Vrin may be set. It is just an example. By setting multiple types of input reference voltage Vrin, it is possible to switch the switch according to the input signal level (and turn on / off the power supply to the amplifier) in finer steps based on the comparison result between the detected voltage and the plurality of reference voltages. As a result, the gain control of the entire amplifier circuit 15 can be performed in finer steps. Thereby, it is possible to control such that the gain of the entire amplifier circuit 15 is increased as the input signal level is smaller.

  In the present embodiment, the gain of the amplifier circuit 15 is controlled according to the input signal level, and as described in the above-described embodiments, the attenuation of the high-frequency signal attenuator 21 according to the output signal level. Quantity control is also performed. That is, the automatic gain adjustment unit 20 controls the high-frequency signal attenuator 21 in accordance with the branch output level from the branch circuit 16. Therefore, according to the television reception amplifying apparatus 108 of this embodiment, more appropriate gain adjustment can be performed according to both the input signal level and the output signal level.

  Here, in this embodiment, each of the switches 81, 82, 83 corresponds to the switch means of the present invention, and each of the amplifiers A1, A2, A3 corresponds to the amplifier of the present invention, and the comparison / control unit. Reference numeral 80 corresponds to the amplifying unit control means of the present invention.

[Eighth Embodiment]
The television reception amplifying apparatus 111 of this embodiment is used in place of the television reception amplifying apparatus 10 in the television reception system 1 described in the first embodiment. Therefore, the same components as those of the television receiving amplifying apparatus 10 (FIG. 2) of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the following description, portions different from FIG. To do.

As shown in FIG. 10, in the television reception amplifying device 111 according to the present embodiment, the television signal input to the input terminal 11 is input to the high frequency signal attenuator 85 via the branch circuit 77.
The high-frequency signal attenuator 85 has a configuration in which three attenuators (first attenuator 85a, second attenuator 85b, and third attenuator 85c) are connected in series. Attenuated as appropriate by 85 b and 85 c and input to the amplifier circuit 15. A branch circuit 77 and an input detection circuit 78 to be described later are exactly the same as the branch circuit 77 and the input detection circuit 78 in the input level adjustment unit 67 constituting the television receiving amplifier 106 (see FIG. 7) of the fifth embodiment, for example. Is.

  The branch output (television signal) from the branch output terminal 16a of the branch circuit 16 is input to the average value detection circuit 89 including the detector 86 and the integration circuit 89a through the filter 26. A comparison circuit 90 is connected to the average value detection circuit 89.

  In the comparison circuit 90, the detection voltage from the integration circuit 89a when the distortion factor of the amplifier circuit 15 is within a predetermined standard range and the output level is the maximum set output level is set as the reference voltage Vref. . Then, as will be described later, the output voltage from the integrating circuit 89a is compared with the reference voltage Vref, and an output signal (control signal) corresponding to the comparison result is output to the switch 92 (and thus to the first attenuator 85a). Output.

  The display circuit 91 is composed of a light emitting diode or the like, and displays whether or not the average value detection circuit 89 is in an operating state based on the output level of the comparison circuit 90. An output signal from the comparison circuit 90 is input to the holding circuit 93 via the switch 92. The holding circuit 93 is for effectively functioning the first attenuator 85a even if the control loop of the first attenuator 85a by the average value detection circuit 89 is opened by turning off the switch 92. That is, when the switch 92 is turned off, the control signal from the comparison circuit 90 is not input, but the control signal level from the comparison circuit 90 immediately before being turned off is held by the holding circuit 93, and the attenuation amount of the first attenuator 85a is also increased. The attenuation amount is held in accordance with the control signal level. As described above, the control signal from the AGC circuit (hereinafter, referred to as “average value AGC circuit”) 150 based on the average value detection composed of the average value detection circuit 89, the comparison circuit 90, and the holding circuit 93 to the first attenuator 85a is: The switch 92 is turned on / off.

  In this embodiment, an example in which the display circuit 91 and the switch 92 are provided has been described. However, these may be omitted, or only one of them may be provided. Further, a ringing circuit such as a buzzer may be provided instead of the display circuit 91. Further, the holding circuit 93 may not be provided. Furthermore, in the present embodiment, a filter 26 (for example, a band pass filter) having a bandwidth of the input frequency band input to the amplifier circuit 15 is interposed between the branch output terminal 16a and the detector 86. However, as described in the first embodiment, the filter 26 is not always necessary, and it may be determined as appropriate depending on the surrounding radio wave environment or the like.

  On the other hand, a smoothing circuit 87a is connected to an interconnection point between the detector 86 and the integrating circuit 89a constituting the average value detection circuit 89, and an output signal from the detector 86 is also input to the smoothing circuit 87a. The peak detector circuit 87 is constituted by the detector 86 and the smoothing circuit 87a. The output (detection voltage) from the peak value detection circuit 87 is amplified by the DC amplification circuit 94 and input to the output level adjustment circuit 95.

  The DC amplifier circuit 94 is connected to an input detection circuit 78 for detecting a branch output level output from the branch output terminal 77a of the branch circuit 77, and detects a change in the input signal level to the high frequency signal attenuator 85. The amplification degree changes depending on the strength of the detected DC signal. The DC amplification circuit 94, the output level adjustment circuit 95, and the peak value detection circuit 87 constitute an AGC circuit (hereinafter abbreviated as “peak value AGC circuit”) 200 based on peak value detection, and is attenuated by the second attenuator 85b. The amount is controlled.

  A switch 95 provided between the output level adjustment circuit 95 and the second attenuator 85b is for turning on / off the AGC function (attenuation amount control of the second attenuator 85b) by the peak value AGC circuit 200. is there. When the switch 95 is off, the attenuation amount of the second attenuator 85b is zero. The DC amplification circuit 94, the branch circuit 77 for controlling the gain of the amplification circuit 94, and the input detection circuit 78 may or may not be provided as appropriate according to the purpose of use.

  A no-signal detection circuit 97 is connected to an interconnection point between the peak value detection circuit 87 and the DC amplification circuit 94. Based on an output signal (detection voltage) from the peak value detection circuit 87, this television reception signal is received. The presence or absence of a television signal input to the amplifying device 111 is detected. The attenuation amount of the third attenuator 85c is controlled by the control signal from the no-signal detection circuit 97.

  Next, an example of the operation of the television reception amplifying apparatus 111 having the above configuration will be described in more detail. A plurality of television signals having different frequencies are input to the input terminal 11, and the input television signals are output to the output terminal 12 via the high-frequency signal attenuator 85, the amplifier circuit 15, the branch circuit 16, and the like. . A part of the output signal is output to the AGC circuits 150 and 200 via the branch output terminal 16a.

  The average value detection circuit 89 collectively detects multi-channel television signals, and among these, the detector 86 has a configuration similar to that of the detection unit 30 described in FIG. Value is different). The integration circuit 89a can be configured by a well-known integration circuit including, for example, a resistor and a capacitor. As a result, the specific configuration is not particularly limited as long as a detection voltage corresponding to the average level of the combined power of the input signal can be output. .

  The detection voltage from the average value detection circuit 89 is input to the comparison circuit 90. At this time, as the reference voltage Vref of the comparison circuit 90, from the average value detection circuit 89 when the level of the output signal from the amplification circuit 15 is the maximum level satisfying the distortion standard inherent in the amplification circuit 15. Is set to the same voltage value as the detection voltage (hereinafter also referred to as “maximum detection voltage value”), the average value AGC circuit 150 amplifies the fluctuation of the input level of the amplifier circuit 15 and the fluctuation of the number of channels of the input signal. The distortion rate of the circuit 15 can always be kept within the standard range, and the maximum gain can be always obtained while the distortion rate satisfies the standard range. Therefore, in the present embodiment, the reference voltage Vref is set to the above maximum detection voltage value as an example.

  Each of the attenuators 85a, 85b, 85c constituting the high-frequency signal attenuator 85 has the same configuration as the high-frequency signal attenuator 21 in the television receiving amplifying apparatus 10 of the first embodiment shown in FIG. The comparison circuit 90 has the same configuration as that of the arithmetic unit 40 in the television receiving amplifying apparatus 10 of the first embodiment.

  Here, consider a case where the input level of the amplifier circuit 15 is in a range (standard range) that sufficiently satisfies the distortion rate standard of the amplifier circuit 15. In this case, since the detection voltage of the average value detection circuit 89 is lower than the reference voltage Vref of the comparison circuit 90, the AGC function by the average value AGC circuit 150 does not work. That is, the attenuation amount of the first attenuator 85a is zero.

  However, the branch output signal output via the branch output terminal 16a of the branch circuit 16 is also input to the peak AGC circuit 200, and the attenuation amount of the second attenuator 85b is controlled by the peak AGC circuit 200.

  In other words, in the range where the distortion does not exceed the limit of the standard, the peak value detection circuit 87 detects the level of the channel with the highest level among the branch input signals composed of a plurality of channels of television signals, and this detection voltage causes The second attenuator 85b is controlled, and the peak value AGC circuit 200 operates so that the output level of the amplifier circuit 15 becomes constant. The output level adjustment circuit 95 that constitutes the peak value AGC circuit 200 is a circuit for adjusting the output level of the amplifier circuit 15, and can be adjusted manually if necessary. Specifically, for example, the calculation unit 40 and the reference voltage circuit 50 shown in FIG. 3 of the first embodiment can be used. At that time, the reference voltage circuit 51 described with reference to FIG. 5 may be used instead of the reference voltage circuit 50. In the former case, the output level of the amplifier circuit 15 can be continuously adjusted, and in the latter case, the output level of the amplifier circuit 15 can be adjusted stepwise.

  The TV signal input level from the input terminal 11 (and hence the input level of the amplifier circuit 15) is detected by the input detection circuit 78, and the detection voltage is input to the DC amplifier circuit 94. The DC amplifier circuit 94 is a variable gain DC amplifier circuit whose amplification degree changes depending on the detection voltage from the input detection circuit 78, and is composed of an operational amplifier or the like. The DC amplification circuit 94 is configured such that the amplification degree is small when the input level to the amplification circuit 15 is large, and the amplification degree is large when the input level is small. However, the detection output of the peak value detection circuit 86 can be input to the output level adjustment circuit 95 at an optimum level. In other words, the output level adjustment range can be made the same regardless of the input level.

  FIG. 11 shows a characteristic example of the output level in the television reception amplifying device 111 of this embodiment provided with the average value AGC circuit 150 and the peak value AGC circuit 200 as described above. That is, in a range where the output level of the amplifier circuit 15 does not exceed the limit (standard range) of the distortion rate of the amplifier circuit 15, the peak value AGC circuit 200 operates to keep the output level constant. On the other hand, in the case where the output level of the amplifier circuit 15 exceeds the distortion limit of the amplifier circuit 15 due to an increase in input power due to an increase in the input level or the number of channels, the comparison constituting the average value AGC circuit 150 is performed. Since the detection voltage input to the circuit 90 becomes larger than the reference voltage Vref, the average value AGC circuit 150 is operated and the output level is lowered so that the distortion rate of the amplifier circuit 15 becomes constant.

  The display circuit 91 outputs the television reception amplifying device 111 in a state where the output level of the amplifier circuit 15 is operating at a constant level or a state where the distortion rate is constant (that is, the average value AGC circuit 150 operates). It is for displaying an operation state such as whether the level is being lowered or not. For example, when the display circuit 91 is configured to display (a light emitting diode or the like is lit) by a control signal output from the comparison circuit 90 when the distortion is used in a constant state, the amplifier circuit 15 It can be easily determined that the output level is controlled by the average value AGC circuit 150. In other words, the display circuit 91 can also be used as a means for warning that the terminal level of the television terminal in the house does not reach the specified level due to a decrease in the output level of the amplifier circuit 15. .

  The switch 92 is used to select whether or not the first attenuator 85a is controlled by the average value AGC circuit 150. In the present embodiment, a state in which the switch 92 is turned on is shown (see FIG. 10), and as a result, the average value AGC circuit 150 and the peak value AGC circuit 200 operate as described above. Further, when the switch 92 is turned off, the average value AGC circuit 150 does not control the first attenuator 85a, and the output level from the amplifier circuit 15 is controlled by the peak value AGC circuit 200. .

  The no-signal detection circuit 97 reduces the attenuation amount of the third attenuator 85c by the detection output from the peak value detection circuit 87 when the input signal disappears or a significant decrease is observed for some reason, and the amplification circuit 15 This is to prevent the noise floor from rising. For example, when there is no input signal, the no-signal detection circuit 97 determines that this is the state based on the detection output from the peak value detection circuit 87. Then, the third attenuator 85c is controlled to reduce the noise increase by, for example, 20 dB.

  In the present embodiment, the state of the first attenuator 85a is held by the holding circuit 93 even if the control signal from the comparison circuit 90 disappears due to the switch 92 being turned off or the like, but the second attenuator 85b and the third attenuator 85c is configured such that the attenuation amount becomes 0 when the control signal is lost. For example, the second attenuator 85 b may be provided on the output side of the amplifier circuit 15 and controlled by the no-signal detection circuit 97.

  By the way, as explained in the first embodiment, the television reception amplifying device 111 of this embodiment also receives the television signals of the respective channels from the respective antennas 2, 3, 4 through the respective coaxial cables 2 a, 3 a, 4 a. Is entered. Then, the input television signal is amplified while the gain is appropriately adjusted as described above, drawn into the house via the coaxial cable 7, and input to the television receiver 9a and the BS tuner 9b.

  As an example, a case where a UHF band television signal is amplified by the television reception amplifying device 111 and transmitted to the home will be described. In a conventional television receiving amplifying device, in the installation, the amplifying device is prevented from being distorted, and the terminal level in the home is set to a constant value (for example, 70 to 80 dBμ in the UHF band) You can watch TV with beautiful images. Therefore, since the number of channels and input levels differ from region to region, installation of the TV receiver amplification device and adjustment of gain, etc., must be performed appropriately in each region, and specialized knowledge and measuring instruments are required. It was.

  Further, as described in the first embodiment, in recent years, terrestrial digital broadcasting has been started in the UHF band, and the number of channels in the UHF band has increased due to simultaneous broadcasting at that time, and conventional television reception has been performed. In the amplifying apparatus for use, there may be a case where the input level of the amplifying apparatus fluctuates after the installation and the input is over.

  Therefore, in the television reception amplifying device 111 of the present embodiment, the reference voltage Vref of the comparison circuit 90 in the average value AGC circuit 150 is used as the television signal having the maximum set output level at which the distortion rate of the amplification circuit 15 satisfies the standard. When the signal is output from the amplifier circuit 15, the television signal is set to a detection voltage detected by the average value detection circuit 89. Thus, when the detection voltage is lower than the reference voltage Vref (that is, when there is a margin in the distortion rate), the peak value AGC circuit 200 controls the output level to be constant. Further, when the detection voltage is higher than the reference voltage Vref (that is, when the distortion rate is an input level exceeding the standard range), the distortion rate is controlled to be constant at the standard value limit.

  Here, the experimental result about the relationship between the output level from the amplifier circuit 15 and a detection voltage is shown. The broken line in FIG. 12A shows the output level characteristic of the amplifier circuit 15 when the input wave number is changed while keeping the distortion rate of the amplifier circuit 15 constant. The solid line is converted from the input level of the detector 86 at which a predetermined detection voltage is obtained and the coupling amount of the branch circuit 16 in the detection voltage characteristic of the detector 86 when the input level is changed with the input wave number as a parameter. The output level of the amplifying circuit 15, that is, the input level of the detector 86 + the value of the coupling amount of the branch output terminal 16a is shown. As shown in FIG. 12A, it can be seen that there is a correlation between the solid line characteristic and the broken line characteristic.

  This experimental circuit is as shown in FIG. 12 (b). As a measurement condition, the distortion rate of the amplifier circuit 15 is made constant as cross modulation (XM) = − 46 dB, and the input wave number is changed from 2 to 7 waves. It was. Under this condition, for example, when the input wave number is 7 waves, the output level is 101.5 dBμ, and when the input wave number is 2 waves, the output level is 108.5 dBμ.

  On the other hand, under the measurement conditions of the detector 86 showing the characteristics of the solid line in FIG. 12A, the detection voltage was measured when the input wave number was changed from 2 to 7 waves and the input level was changed at each wave number. The results are shown in FIG. Here, for example, when the detection voltage is 0.8 V, the input level to the detector 86 at each wave number is 91 dBμ for 7 waves and 98.7 dBμ for 2 waves. If the coupling amount is added, the output level of the amplifier circuit 15 can be calculated. In this case, it can be seen that the output level is 101 dBμ for two waves, and the output level is 108.7 dBμ for seven waves. Thus, by adjusting the detection voltage to a predetermined value, the output level that is substantially correlated with the distortion rate of the measured value is obtained for both the input level change and the input wave number change. You can see that

  For example, as the standard channel number determined in Better Living (BL), when analog wave = 7 waves, terrestrial digital wave = 9 waves (10 dB lower than analog wave), gain = 30 dB, maximum output = 100 dBμ, distortion Considering the television receiving amplifying device 111 with the rate = −46 dB as a standard, the switch 96 is turned off and the switch 92 is turned on, and a signal is inputted so as to obtain the above distortion rate. In this case, the detection voltage when the distortion becomes −46 dB is a reference. Then, the reference voltage Vref is set so that the average value AGC circuit 150 is operated by comparing the reference voltage Vref with a value larger or smaller than the reference voltage Vref. The output level at this time is unique by the amplifier circuit 15.

  Next, the switch 96 is turned on and the switch 92 is turned on. Thus, the television receiving amplifying device 111 is controlled so that the output level is constant while the input level satisfies the distortion standard, and when the distortion exceeds the standard, the distortion is constant. The output level is controlled so as to decrease. For this reason, in a state where the amplifying device 111 is installed, a stable use state can always be maintained even if the input signal varies due to the above situation. In addition, it also has the convenience of easy installation without specialized knowledge or measuring instruments.

  Next, a better example of the handleability of the television reception amplifying device 111 of the present embodiment will be described. In this example, the output level is set in consideration of the terminal level in the house. In general, the output level at the TV terminal in the house is 70 to 80 dBμ for both VHF and UHF, and approximately 55 dBμ or more for BS. Focusing on this point, a method for easily setting the output level of the television terminal to the optimum value in the television receiving system 1 will be described.

  Here, the UHF band will be described as an example. For example, consider four distributions of television signals as shown in the television reception system 1 (four distributions are performed by the distributor 6 in FIG. 1). Considering 770 MHz as a reference, the coaxial cable is 30 m, the attenuation is about 5 dB, the distribution loss of the distributor 6 which is a four distributor is about 8 dB, and the total loss is about 13 dB. If the output level of the TV terminal is 80 dBμ, for example, the output level of the TV reception amplifying device 111 may be equal to the sum of losses + the TV terminal level, and therefore the output level of the amplifying device 111 only needs to be set to 93 dBμ. become. In other words, if the loss of various transmission devices such as coaxial cables and distributors in a standard joint reception system (for example, 2 distribution, 4 distribution, 6 distribution, 8 distribution, etc.) is modeled and set in advance, The television reception system 1 using the television reception amplifying device 111 can easily set the output level of the television terminal to an optimum level regardless of the input level.

  In addition, in order to deal with the modeled loss, in this embodiment, for example, the loss in a system such as 2 distribution, 4 distribution, 6 distribution, and 8 distribution can be handled by one amplification device 111. A variable means 46 such as a volume is provided. Specifically, for example, this can be realized by switching a reference voltage (not shown) included in the output level adjustment circuit 95 by the variable means 46. By using the amplifying device 111 configured as described above, the output level of the television terminal can be set more easily at the installation site simply by adjusting the variable means 46 in accordance with the situation of the system.

  FIG. 14A shows a perspective view of the television reception amplifying apparatus 111 of the present embodiment, and FIG. 14B shows variable means for switching for each system so that the modeled loss can be selected. 46 is an enlarged view of 46. FIG. That is, a reference voltage corresponding to each distribution loss (in this embodiment, direct connection, 2 distribution, 4 distribution, 6 distribution, and 8 distribution) is set, and by switching the variable means 46, any reference voltage is set. Can be set.

  FIG. 14C shows variable means for making the output level selectable in a plurality of steps by providing the comparison circuit 90 with a plurality of reference voltages Vref so that a plurality of set output levels can be set. 47 shows an enlarged view. That is, each reference voltage Vref corresponding to each output level (90 dBμ, 100 dBμ, 110 dBμ, and 120 dBμ in this embodiment) is set, and by switching the variable means 47, any reference voltage Vref ( Output level).

  According to the television reception amplifying apparatus 111 of the present embodiment described above, television reception amplification in which AGC control is performed by an appropriate method for fluctuation factors such as input signal level fluctuations and changes in input power due to wave number increases. Equipment can be provided.

  Specifically, until the detection voltage from the average value detection circuit 89 reaches the reference voltage Vref of the comparison circuit 90 constituting the average value AGC circuit 150, that is, in a range where the distortion factor of the amplifier circuit 15 does not exceed the standard. The peak value AGC circuit 200 keeps the output level constant, and when the distortion rate of the amplifier circuit 15 exceeds the reference level, the average value AGC circuit 150 lowers the output level so that the distortion rate becomes constant. is there. The television reception amplifying device 111 configured as described above is not affected by the level of the input signal and the number of channels of the input signal at the time of installation, and also after the installation, the level of the input signal and the number of channels of the input signal are not affected. Can be installed easily without specialized knowledge or measuring instruments.

  In addition, since the two AGC circuits (the average value AGC circuit 150 and the peak value AGC circuit 200) are configured by using the detector 86 in common, the configuration of the AGC circuit is simplified, and the cost of the entire amplifying apparatus 111 is reduced. It becomes possible.

  Further, as shown in FIG. 14B, the output level of the amplifying device is adjusted to a value obtained by modeling the loss of the distribution system or the like of the television reception system (for example, 2 distribution system, 3 distribution system,...). Therefore, by adjusting the output of the amplification device according to the configuration of the television receiving system, the terminal level can be easily fixed to an appropriate level, and a highly convenient amplification device can be provided. .

  Furthermore, by providing the no-signal detection circuit 97, for example, when there is no input signal, the attenuation amount of the third attenuator 85c is set to zero to prevent the noise floor of the amplifier circuit 15 from rising, and noise is added to the system. It is possible to prevent adverse effects.

  Furthermore, in this embodiment, since the display circuit 91 is provided on the output side of the comparison circuit 90, the first attenuator 85a is operated by the average value AGC circuit 150 in a state where the amplification device 111 is installed. It is possible to notify the installer or the like that the state, that is, the state in which the output level is lowered so that the distortion rate becomes constant. The display by the display circuit 91 is also a display for warning that the output level is lowered, and can be used to indicate that the terminal level at the television terminal in the house may be lowered from the optimum level.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. In the present embodiment, the high frequency signal attenuator 85 corresponds to the signal attenuating means of the present invention (Claim 15). Of these, the first attenuator 85a corresponds to the first attenuating means of the present invention, and the second attenuator 85b. Corresponds to the second attenuating means of the present invention, the third attenuator 85c corresponds to the third attenuating means of the present invention, the fourth attenuator 132 corresponds to the fourth attenuating means of the present invention, and the no-signal detection circuit. 97 corresponds to the no-signal detection means of the present invention, the display circuit 91 corresponds to the display means of the present invention (claim 24), and the switch 92 corresponds to the control switching means of the present invention. Further, the adder 134 and the inverting circuit 133 constitute the output adjusting means of the present invention.

[Ninth Embodiment]
In the eighth embodiment, the three attenuators 85a, 85b, and 85c constituting the high-frequency signal attenuator 85 are individually controlled. However, in the present embodiment, one attenuator 21 (first The same as the high-frequency signal attenuator 21 of the first embodiment and the like, and the attenuation amount of this one attenuator can be controlled based on each control signal corresponding to each of the attenuators 85a, 85b, 85c. Yes. In the following description, the same reference numerals are given to the same components as those in the first and eighth embodiments, and the detailed description thereof is omitted.

  That is, as shown in FIG. 15, in the television reception amplifying device 112 of this embodiment, the output signal from the average value AGC circuit 150, the output signal from the peak value AGC circuit 200, and the no-signal detection circuit 97 The output signal is added (synthesized) by an adder 130 composed of an operational amplifier or the like, and the addition result is output to the high-frequency signal attenuator 21. The high frequency signal attenuator 21 is configured such that the amount of attenuation is controlled by the output (addition result) of the adder 130.

  Thereby, all of the control signal from the average value AGC circuit 150, the control signal from the peak value AGC circuit 200, and the signal from the no-signal detection circuit 97 can be reflected in the attenuation amount control of the high frequency signal attenuator 21. In addition, the configuration of the high-frequency signal attenuator 21 can be simplified.

[Tenth embodiment]
The television receiving amplifying device 113 of the present embodiment shown in FIG. 16 is mainly different from the television receiving amplifying device 111 (see FIG. 10) of the eighth embodiment in that the output signal from the branch circuit 16 is the output terminal as it is. This is a point that is not output from 12 but output after being further attenuated by an attenuator. Therefore, the other components similar to those of the television reception amplifying device 111 of the eighth embodiment are denoted by the same reference numerals as those in FIG. 10, and detailed description thereof is omitted.

  As shown in FIG. 16, in the television reception amplifying device 113 of the present embodiment, a fourth attenuator 132 is provided between the branch circuit 16 and the output terminal 12. On the other hand, both the detection voltage from the peak value detection circuit 87 and the detection voltage from the average value detection circuit 89 are added by an adder 134 constituted by an operational amplifier or the like. Then, the addition result is input to the inverting circuit 133.

  The inverting circuit 133 reduces the attenuation amount of the fourth attenuator 132 as the addition result of each detection voltage that is a signal from the adder 134 increases, and conversely the fourth attenuator 132 as the addition result decreases. A control signal that increases the amount of attenuation is generated and output to the fourth attenuator 132. That is, the fourth attenuator 132 is configured to control the fourth attenuator 132 by inverting the detected signal so that the operation of the high-frequency signal attenuator 85 at the input stage is reversed. It is.

  With such a configuration, the output signal output from the output terminal 12 can be maintained at a constant output level even when a high input voltage is applied to the input terminal 11 as compared with the eighth and ninth embodiments. effective. In the ninth embodiment, the fourth attenuator 132 and the inverting circuit 133 and the adder 134 for controlling the fourth attenuator 132 are provided between the branch circuit 16 and the output terminal 12 as in the present embodiment. You may do it.

[Modification]
The embodiment of the present invention is not limited to the above-described embodiment, and it goes without saying that various forms can be adopted as long as it belongs to the technical scope of the present invention.

  For example, in the television receiving amplifying apparatus 10 (FIG. 2) of the first embodiment, as in the television receiving amplifying apparatus 101 (FIG. 4) of the second embodiment, a manual control unit 61 is provided to attenuate the high frequency signal. The control of the device 21 may be selected from either a control signal from the automatic gain adjustment unit 20 or a control signal from the manual control unit 61. The same applies to the television receiver amplifier 102 (FIG. 5) of the third embodiment.

  Further, in the first embodiment, the reference voltage circuit 50 is configured so that the reference voltage Vref can be continuously variably set by the variable resistor VR1 as shown in FIG. Alternatively, the reference voltage circuit 51 in the third embodiment (FIG. 5) may be variably provided in stages. Further, as in the third embodiment, a level display circuit including the first comparison unit 32 and the first display unit 33 may be provided, or a level display circuit including the second comparison unit 42 and the second display unit 43 may be provided. It may be provided.

  In the television reception amplifying apparatus 102 (FIG. 5) of the third embodiment, not only the above-described level display circuits are provided together, but only one of them may be provided. Further, instead of the reference voltage circuit 51, the reference voltage circuit 50 in the first embodiment may be provided.

  Further, in the television receiving amplifying device 105 (FIG. 6) of the fourth embodiment, an example in which the input level adjusting unit 66 is provided in the previous stage of the AGC amplifying unit 101a is shown, but instead of this input level adjusting unit 66, For example, the input level adjustment unit 67 in the television reception amplification device 106 (FIG. 7) of the fifth embodiment may be provided, or the input level adjustment unit 68 in the television reception amplification device 107 (FIG. 8) of the sixth embodiment. May be provided. Further, for example, instead of the input level adjusting unit 66, an input side gain adjusting unit 69 in the television receiving amplifying apparatus 108 (FIG. 9) of the seventh embodiment may be provided.

  The same applies to the other fifth to seventh embodiments. That is, in the fourth to seventh embodiments, each of the input level adjustment units 66, 67, 68 or the input side gain adjustment unit 69 is different from each other. The input level adjustment unit or the input-side gain adjustment unit 69 may be replaced with the above-described configuration. Furthermore, the input level adjustment units 66, 67, 68 or the input-side gain adjustment unit 69 in the fourth to seventh embodiments are used in the television receiving amplification devices 10, 101, 102 of the first to third embodiments. It may be provided on the input side, or may be provided on the input side (preceding stage of the high-frequency signal attenuator) in each of the television reception amplifying devices 111, 112, and 113 of the eighth to tenth embodiments described later.

  In particular, the input level adjusting units 66, 67, 68 or the input side gain adjusting unit 69 in the fourth to seventh embodiments are provided on the input side in each of the television reception amplifying devices 10, 102 in the first or third embodiment. In this case, it may be provided between the input terminal 11 and the changeover switch 14, or may be provided before the high frequency signal attenuator 21. In the latter case, when the changeover switch 14 is switched to the passing line 19 side, the television signal from the input terminal 11 is directly supplied to the amplifier circuit without passing through the input level adjusting units 66, 67, 68 or the input side gain adjusting unit 69. 15 will be input.

  Furthermore, in the eighth embodiment, the output level setting change function by the variable means 46 shown in FIG. 14B and the output level setting change function by the variable means 47 shown in FIG. Needless to say, the present invention is not limited to the embodiment and can be similarly adopted in other embodiments.

  Further, in order to prevent the noise figure from being lowered due to the loss interposed between the input terminal 1 and the amplifier circuit 15, a separate amplifier circuit is provided in front of the branch circuit, the high frequency signal attenuator, etc. that cause the loss. It goes without saying. Specifically, for example, between the input terminal 11 and the high frequency signal attenuator 21 in the television reception amplifying device 101 of the second embodiment, or branched from the input terminal 11 in the television reception amplifying device 111 of the eighth embodiment. An amplifier circuit may be provided between the circuit 77 and the existing amplifier circuit 15.

  Further, for example, in the television reception amplifying apparatus 111 of the eighth embodiment, an amplifier is connected to the preceding stage of each of the first attenuator 85a, the second attenuator 85b, and the third attenuator 85c as shown in FIG. An amplifier may also be connected to the output side of the stage attenuator (first attenuator 85a in FIG. 17). That is, one amplifier circuit 15 is configured by the first amplifier 141, the second amplifier 142, the third amplifier 143, and the fourth amplifier 144, and between the first amplifier 141 and the second amplifier 142, The second attenuator 85b is connected, the third attenuator 85c is connected between the second amplifier 142 and the third amplifier 143, and the first attenuator 85a is connected between the third amplifier 143 and the fourth amplifier 144. Is connected.

  As in the eighth embodiment (FIG. 10), the second attenuator 85b is controlled by the peak value AGC circuit 200, the first attenuator 85a is controlled by the average value AGC circuit 150, and the third attenuator 85c is not used. It is controlled by the signal detection circuit 97. According to this configuration, similarly to the eighth embodiment, it is possible to provide a television reception amplifying device 114 with an automatic gain adjustment function that can be used in both a weak electric field region and a strong electric field region.

  In addition, in addition to controlling the high-frequency signal attenuator 85 (each attenuator 85a, 85b, 85c), the bias of the first, second, third, and fourth amplifiers 141, 142, 143, and 144 is input. You may comprise so that it may control based on a signal level.

  In the television receiving amplifying apparatus 10 (FIG. 2) of the first embodiment, the television signal amplified by the amplifier circuit 15 is level-adjusted outside the AGC loop (after the branch circuit 16) and output. You may do it. Specifically, a high-frequency signal attenuator 120 for adjusting the output level is provided between the branch circuit 16 and the output terminal 12 as in the television reception amplifying device 115 shown in FIG.

  As described above, the output level can be adjusted by adjusting the reference voltage Vref. However, if the output level is adjusted by the reference voltage Vref, the operation range of the AGC function is narrowed, and the power of the amplifier circuit 15 is maximized. It becomes difficult to utilize it to the limit. Therefore, if the reference voltage Vref is set to a value that can maximize the power of the amplifier circuit 15 and a high-frequency signal attenuator 120 for adjusting the output level is provided outside the AGC loop (see FIG. 18), the amplifier circuit 15 It is possible to provide the television receiving amplifying device 115 that makes the best use of the power of the receiver.

  The technique of providing the high-frequency signal attenuator 120 for adjusting the output level between the branch circuit 16 and the output terminal 12 as shown in FIG. 18 is not limited to the case of the first embodiment, and each of the other embodiments Needless to say, the present invention can also be applied to an amplifying apparatus for receiving television (FIGS. 2, 4 to 10, and 15 to 17). However, when applied to the television reception amplifying device 113 (FIG. 16) of the tenth embodiment, a high-frequency attenuator 120 for adjusting the output level may be provided between the fourth attenuator 132 and the output terminal 12.

  In the eighth embodiment (see FIG. 10), the third attenuator 85c is controlled by the no-signal detection circuit 97. However, this configuration is merely an example, and the third attenuator 85c and the no-signal are not shown. The detection circuit 97 may be omitted. However, in order to prevent the noise floor from rising and to prevent the noise from adversely affecting the system, it is preferable to provide the third attenuator 85c and the no-signal detection circuit 97 as in the eighth embodiment.

It is explanatory drawing which shows schematic structure of the television receiving system of embodiment. 1 is a block diagram illustrating a schematic configuration of a television reception amplification device according to a first embodiment. FIG. It is a circuit diagram which shows the internal structure of the amplifier for television reception of 1st Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 2nd Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 3rd Embodiment. It is a block diagram which shows schematic structure of the amplification device for television reception of 4th Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 5th Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 6th Embodiment. It is a block diagram which shows schematic structure of the amplifier for television reception of 7th Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 8th Embodiment. It is a graph which shows an example of the output level characteristic in the amplification apparatus for television reception of 8th Embodiment. It is explanatory drawing for demonstrating the output characteristic of the amplifier circuit which comprises the amplifier for television reception of 8th Embodiment, (a) is a graph which shows the relationship between the output characteristic of an amplifier circuit, and a detection voltage, (b). Shows the measurement system used in the experiment for obtaining the graph of (a). It is a graph which shows the result of having measured the detection voltage when changing an input level for every several types of wave numbers. It is explanatory drawing which shows the television receiver amplifier of 8th Embodiment, (a) is a perspective view, (b) is an enlarged view of the variable means 46, (c) is an enlarged view of the variable means 47. It is a block diagram which shows schematic structure of the amplifier for television reception of 9th Embodiment. It is a block diagram which shows schematic structure of the television receiving amplifier of 10th Embodiment. It is a block diagram which shows the other structural example of the amplifier for television reception of 8th Embodiment. It is a block diagram which shows the other structural example of the amplification apparatus for television reception of 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Television receiving system, 2 ... VHF antenna, 2a, 3a, 4a, 5, 7 ... Coaxial cable, 3 ... UHF antenna, 4 ... BS antenna, 6 ... Distributor, 8 ... Television terminal, 9 ... VU / BS Waver, 9a ... TV receiver, 9b ... BS tuner, 10,101,102,105,106,107,108,111,112,113,114,115 ... Amplifier for TV reception, 11 ... Input terminal, 12 ... Output terminal, 13 ... Input filter, 14, 73 ... Switch, 15 ... Amplifier circuit, 16,77 ... Branch circuit, 16a ... Branch output terminal, 17 ... Output filter, 18 ... Power supply separation filter, 19,75 ... Pass Lines 20, 63 ... automatic gain adjustment unit, 21, 85, 120 ... high frequency signal attenuator, 26 ... filter, 30 ... detection unit, 32 ... first comparison unit, 33 ... first display unit, 4 ... Calculation unit, 42 ... Second comparison unit, 43 ... Second display unit, 46,47 ... Variable means, 50,51 ... Reference voltage circuit, 61 ... Manual control unit, 66-69 ... Input level adjustment unit, 71, 72 ... input attenuator, 77a ... branch output terminal, 78 ... input detection circuit, 79, 79a, 90 ... comparison circuit, 80 ... comparison / control unit, 81 ... first switch, 82 ... second switch, 83 ... third Switch, 85a ... 1st attenuator, 85b ... 2nd attenuator, 85c ... 3rd attenuator, 86 ... Detector, 87 ... Peak value detection circuit, 87a ... Smoothing circuit, 89 ... Average value detection circuit, 89a ... Integration Circuit, 91 ... Display circuit, 92, 96 ... Switch, 93 ... Holding circuit, 94 ... DC amplification circuit, 95 ... Output level adjustment circuit, 97 ... No signal detection circuit, 101a, 101b, 103 ... AGC amplification unit, 106 ... Amplification equipment, 1 0, 134 ... adder, 132 ... fourth attenuator, 133 ... inverting circuit, 141 ... first amplifier, 142 ... second amplifier, 143 ... third amplifier, 144 ... fourth amplifier, 150 ... average value AGC circuit, 200: Peak value AGC circuit, A1 to A3: Amplifier, VR1: Variable resistor

Claims (24)

A television reception amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side,
Signal attenuating means for attenuating the television signal input from the input terminal;
Amplifying means for amplifying the television signal attenuated by the signal attenuating means;
An output branching means for outputting the television signal amplified by the amplification means to the output terminal side and branching a part of the amplified television signal;
Automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means based on the television signal branched by the output branching means so that the television signal amplified by the amplifying means has a predetermined level;
Manual gain adjusting means for manually and continuously variably setting the attenuation amount of the signal attenuation means;
An adjustment method switching means capable of selectively switching either the automatic gain adjustment means or the manual gain adjustment means;
With
The automatic gain adjusting means includes
A signal level detector for detecting a television signal branched by the output branching means;
When the detection voltage obtained by the detection at the signal level detection unit is compared with a predetermined control reference voltage, and the detection voltage is greater than the control reference voltage, the level corresponding to the detection voltage An arithmetic unit for controlling the attenuation amount of the signal attenuation means by outputting a control signal of
Consists of
The television reception amplifying apparatus, wherein the signal attenuating means has an attenuation controlled by either the automatic gain adjusting means or the manual gain adjusting means selected by the adjusting method switching means. A television reception amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side,
Amplifying means for amplifying the television signal;
An output branching means for outputting the television signal amplified by the amplification means to the output terminal side and branching a part of the amplified television signal;
A signal attenuating means for attenuating the TV signal input from the input terminal;
The television signal input from the input terminal is attenuated by the signal attenuating means and then the attenuated television signal is output to the amplifying means side, or the amplifying means is not passed through the signal attenuating means. Transmission path switching means for selectively switching either one of the output to the side,
When the transmission path switching means is selected to output the television signal after attenuation by the signal attenuation means to the amplification means side, the output so that the television signal amplified by the amplification means becomes a predetermined level. Automatic gain adjusting means for controlling the attenuation of the signal attenuating means based on the television signal branched by the branching means;
With
The automatic gain adjusting means includes
A signal level detector for detecting a television signal branched by the output branching means;
The detection level obtained by the detection at the signal level detection unit is compared with a predetermined control reference voltage. When the detection voltage is greater than the control reference voltage, the level corresponding to the detection voltage is An arithmetic unit for controlling the attenuation amount of the signal attenuating means by outputting a control signal;
A television receiver amplifying device comprising: First comparison means for comparing the detected voltage with a predetermined first reference voltage for comparison;
First display means for displaying a comparison result by the first comparison means;
With
The first reference voltage for comparison is set to a detection voltage value from the signal level detection unit when a television signal amplified by the amplification means has a predetermined level. 3. The television receiving amplifying device according to 2. Second comparison means for comparing the control signal output from the arithmetic unit with a predetermined second reference voltage for comparison;
Second display means for displaying a comparison result by the second comparison means;
With
The second reference voltage for comparison is calculated when the distortion factor of the amplifying means is within a predetermined standard range and the television signal amplified by the amplifying means is at a preset maximum level. The television receiver amplifier according to any one of claims 1 to 3, wherein the voltage value of the control signal from the unit is set. 5. An input attenuating means for attenuating a television signal input to the input terminal and outputting the signal to the signal attenuating means is provided between the input terminal and the signal attenuating means. The television receiving amplifying device according to any one of the above. A television reception amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side,
Signal attenuating means for attenuating the television signal input from the input terminal;
Amplifying means for amplifying the television signal attenuated by the signal attenuating means;
An output branching means for outputting the television signal amplified by the amplification means to the output terminal side and branching a part of the amplified television signal;
Automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means based on the television signal branched by the output branching means so that the television signal amplified by the amplifying means has a predetermined level;
With
The automatic gain adjusting means includes
A signal level detector for detecting a television signal branched by the output branching means;
The detection level obtained by the detection at the signal level detection unit is compared with a predetermined control reference voltage. When the detection voltage is greater than the control reference voltage, the level corresponding to the detection voltage is An arithmetic unit for controlling the attenuation amount of the signal attenuating means by outputting a control signal;
Consists of
Furthermore, an input attenuating means for attenuating a television signal input to the input terminal and outputting the signal to the signal attenuating means is provided between the input terminal and the signal attenuating means. Amplifying device for reception. The TV signal input to the input terminal is attenuated by the input attenuating means and then output to the signal attenuating means, or it is directly output to the signal attenuating means without going through the input attenuating means, The television receiving amplifying device according to claim 5 or 6, further comprising an input side path switching means capable of selectively switching any one of the above. An input branching means for branching a part of the television signal input to the input terminal;
Input detection means for detecting a television signal branched by the input branch means;
Input comparison means for comparing a detection voltage obtained by the detection by the input detection means with a predetermined input reference voltage;
With
The input side path switching means outputs the input television signal as it is to the signal attenuating means when the input comparison means determines that the detection voltage is lower than the input reference voltage, and the input comparison means 8. The television according to claim 7, wherein when the detected voltage is determined to be equal to or higher than the input reference voltage, the input television signal is attenuated by the input attenuating means and then output to the signal attenuating means. Amplifying device for reception. An input branching means for branching a part of the television signal input to the input terminal;
Input detection means for detecting a television signal branched by the input branch means;
An input comparison means for comparing a detection voltage obtained by the detection by the input detection means with a predetermined input reference voltage, and outputting a signal according to the comparison result;
With
The television receiving amplifying apparatus according to claim 5 or 6, wherein the input attenuating means is configured such that the amount of attenuation is controlled in accordance with a signal from the input comparing means. The amplifying means comprises a plurality of amplifying units for amplifying the input television signal,
Each amplifying unit is provided with a switch means for short-circuiting between the input and output of the amplifying unit,
An input branching means for branching a part of the television signal input to the input terminal;
Input detection means for detecting a television signal branched by the input branch means;
Amplifying unit control means for controlling the state of the switch means corresponding to each amplifying unit and the power supply state to each amplifying unit based on the detection voltage obtained by the detection by the input detecting unit;
With
The amplifying unit control means turns on the corresponding amplifying units corresponding to the detected voltage among the amplifying units so that the amplification factor by the amplifying unit decreases as the detected voltage increases. 5. The television receiving amplifying device according to claim 1, wherein the input and output are short-circuited and the power supply is stopped. A television reception amplifying device for amplifying a television signal received by a television broadcast wave receiving antenna and transmitting the amplified signal to a terminal side,
Signal attenuating means for attenuating the television signal input from the input terminal;
Amplifying means comprising a plurality of amplifying units for amplifying the television signal attenuated by the signal attenuating means;
An output branching means for outputting the television signal amplified by the amplification means to the output terminal side and branching a part of the amplified television signal;
Automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means based on the television signal branched by the output branching means so that the television signal amplified by the amplifying means has a predetermined level;
With
The automatic gain adjusting means includes
A signal level detector for detecting a television signal branched by the output branching means;
The detection level obtained by the detection at the signal level detection unit is compared with a predetermined control reference voltage. When the detection voltage is greater than the control reference voltage, the level corresponding to the detection voltage is An arithmetic unit for controlling the attenuation amount of the signal attenuating means by outputting a control signal;
Consists of
In addition,
Provided for each amplification unit, switch means for short-circuiting between the input and output of the amplification unit,
An input branching means for branching a part of the television signal input to the input terminal;
Input detection means for detecting a television signal branched by the input branch means;
Amplifying unit control means for controlling the state of the switch means corresponding to each amplifying unit and the power supply state to each amplifying unit based on the detection voltage obtained by the detection by the input detecting unit;
With
The amplifying unit control means turns on the corresponding amplifying units corresponding to the detected voltage among the amplifying units so that the amplification factor by the amplifying unit decreases as the detected voltage increases. And a non-operating state in which the power supply is stopped while the input and output are short-circuited. The control reference voltage is a collective detection by the signal level detection unit of the television signals obtained by amplifying the television signals of a plurality of channels by the amplification means so that the distortion rate of the amplification means is within a predetermined standard range. It is set to the detection voltage value obtained by these. The amplification device for television reception in any one of Claims 1-11 characterized by the above-mentioned. The control reference voltage is changed continuously or stepwise so that the output level of the television receiving amplifier can be changed continuously or stepwise within a range in which the distortion factor of the amplification means falls within a predetermined standard range. 13. The television receiving amplifying device according to claim 1, further comprising control reference voltage setting means that can be set to Regardless of the increase or decrease in the number of channels of the television signal input to the television reception amplification device, the output level of the television reception amplification device is set within a range in which the distortion factor of the amplification means is within a predetermined standard range. 13. The television receiving amplifying device according to claim 1, further comprising a control reference voltage setting unit capable of setting the control reference voltage continuously or stepwise so as to be constant. It is used to amplify a television signal received by a TV broadcast wave receiving antenna and transmit it to the terminal side, attenuate the television signal input from the input terminal by a signal attenuating means, A television receiving amplifying device configured to amplify a television signal by an amplifying means and output from the output terminal,
Output branching means for branching a part of the television signal amplified by the amplification means;
Automatic gain adjusting means for controlling the attenuation amount of the signal attenuating means based on the television signal branched by the output branching means so that the television signal amplified by the amplifying means has a predetermined level;
With
The automatic gain adjusting means includes a plurality of AGC circuits configured to control the attenuation amount of the signal attenuating means based on a detection voltage obtained by detecting the television signal branched by the output branching means, and Each AGC circuit is configured to perform the detection by a different detection method,
Attenuation amount of the signal attenuation means is controlled by a plurality of the AGC circuits. As the AGC circuit,
An average value detection circuit for detecting an average value of a television signal branched by the output branching means, and a distortion factor of the amplification means is within a predetermined standard range, and a television signal amplified by the amplification means is preset. A detection voltage obtained by detecting the television signal at the maximum level detected by the average value detection circuit as a control reference voltage, and comparing the control reference voltage and the detection voltage by the average value detection circuit, A comparison circuit for controlling the attenuation amount of the signal attenuation means according to a comparison result, and an AGC circuit by means of average value detection,
A peak value detection circuit for detecting a peak value of the television signal branched by the output branching means, and an output level adjustment circuit for controlling the attenuation amount of the signal attenuation means based on a detection voltage by the peak value detection circuit. AGC circuit with peak value detection
With
The signal attenuating means comprises a first attenuating means and a second attenuating means connected in series on the transmission path of the television signal,
The attenuation amount of the first attenuation means is controlled by an AGC circuit based on the average value, and the attenuation amount is controlled by an AGC circuit based on the peak value. 15. The amplification device for television reception according to 15. The average value detection circuit comprises a detector for detecting a television signal branched by the output branching means, and an integration circuit for obtaining an average value of the television signal by integrating the detection signal by the detector.
The television reception amplification according to claim 16, wherein the peak value detection circuit includes the detector constituting the average value detection circuit, and a smoothing circuit for smoothing a detection signal from the detector. apparatus. The preset maximum level takes into account the loss occurring on the transmission path to the terminal side of the television signal output from the television receiving amplification device to the terminal side in advance, and the television at the terminal side The amplification device for television reception according to claim 16 or 17, wherein the level of the signal is set to a value that becomes a specified level.   19. The television receiving amplifying device according to claim 18, wherein the control reference voltage can be set continuously or stepwise so that a plurality of types of the preset maximum levels can be set. A DC amplification circuit is provided between the peak value detection circuit and the output level adjustment circuit,
The television receiving amplifier according to any one of claims 16 to 19, wherein the direct current amplifier circuit is configured such that an amplification degree changes in accordance with a level of a television signal input from the input terminal. . No-signal detection means for detecting the presence or absence of input of a television signal to the television reception amplification device based on the output from the peak value detection circuit;
Third attenuation means provided on a transmission path from the input terminal to the amplification means;
With
The television receiving amplifying apparatus according to any one of claims 16 to 20, wherein the third attenuating unit is configured to control an attenuation amount according to a detection result by the no-signal detecting unit.   The television according to any one of claims 16 to 21, further comprising control switching means capable of selectively switching whether or not the attenuation amount of the first attenuation means is controlled by the AGC circuit based on the average value. Amplifying device for reception. A fourth attenuating means provided on a transmission line from the output branching means to the output terminal;
According to the output from at least one of the AGC circuit based on the peak value detection or the AGC circuit based on the average value detection, the fourth attenuation characteristic is opposite to the attenuation characteristic of the first attenuation means or the second attenuation means. Output adjustment means for controlling the attenuation amount of the attenuation means;
23. The television receiving amplifying apparatus according to claim 16, further comprising: The AGC circuit based on the average value is provided with display means for displaying when the input level to the comparison circuit becomes higher than the control reference voltage. The television receiving amplifying device according to any one of the above.

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