JP2002237728A - Reception amplifying device and amplifying element protecting method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reception amplifying device for radio communication and an amplifying element protecting method for the reception amplifying device, by which the destruction of amplifying elements due to an excess input can be prevented. SOLUTION: This reception amplifying device is provided with a branching means for branching a reception signal inputted to an amplifier circuit, a detecting means for detecting a branched signal, and for generating a DC detection voltage, a comparing means for comparing the generated detection voltage with a prescribed threshold voltage set so as to be lower than the maximum allowable power of amplifying elements constituting the amplifier circuit, and for outputting a compared result signal based on whether or not the detection voltage exceeds the threshold voltage, and a bias ON/OFF means for turning on power supply to a bias circuit when the detection voltage is lower than the threshold voltage, and for turning off the power supply in the other case according to the compared result signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving amplifying device used in high-frequency wireless communication and a method for protecting an amplifying element of the receiving amplifying device. And a method for protecting an amplification element of a reception amplification device.

[0002]

2. Description of the Related Art Conventionally, a receiving apparatus for wireless communication such as satellite communication, a receiving circuit of a satellite broadcasting receiving apparatus, and the like have a low NF (Noise Fidelity) in order to receive weak radio waves from a satellite.
gure: noise figure = noise ratio between input signal and output signal)
Is used.

In recent years, with the progress of wireless communication, communication distances such as wireless LAN and wireless communication for transmitting video signals and audio signals are relatively short (several meters to hundreds of meters). Moreover, the type of communication (mobile communication) in which the sender moves within the range has been widely used. In these communication devices, it is difficult to increase the transmission power because the transmission device is required to be small and power-saving. To respond to this problem, the receiving circuits of these wireless communication devices
Low noise amplifier circuits have come to be used.

As a method for realizing a communication distance of several hundreds of meters with a small transmission power (several tens of mW), there are a method using a low NF receiving device and a method using a high gain receiving antenna. The former method is most effective because the gain receiving antenna has strong directivity and the antenna shape becomes large.

[0005] Fig. 5 shows a conventional reception amplifier circuit generally used at present. The signal received via the receiving antenna 1 is band-limited by the band-pass filter 2, amplified by multi-stage connected low-NF amplifiers 8 and 9, and output to the mixer 12. The bias circuits 10 and 11 supply a bias voltage to the amplifier circuits 8 and 9. As described above, in the conventional circuit, no protection means is provided for the amplifier element from excessive input.

In a low NF reception amplifier circuit, an HEMT (High Electoron Mobility Trangis) is usually used as an amplifying element.
ter: high electron mobility transistor) and NF
Is not inserted between the receiving antenna and the first-stage HEMT so as not to deteriorate. The HEMT is a type of semiconductor transistor using a GaAs-based compound semiconductor as a material, and is often used for high-frequency signal processing.

As a result, the high-frequency signal received by the receiving antenna is directly input to the HEMT. If the input power exceeds the specified maximum input power (allowable power) of the HEMT, the element is destroyed. cause. Further, in general, the HEMT has a low maximum inputtable power, and thus such a problem is likely to occur.

Therefore, in the case of the conventional circuit shown in FIG. 5, the signal transmitting side switches the output power so that the input level to the receiving amplifier circuit does not exceed the allowable power of the HEMT, or artificially limits the communication distance. There is a drawback that it is necessary to take such measures. In addition, there is a problem that high transmission output power is radiated in the vicinity of the receiving device due to an operation error or the like, which leads to destruction of the amplification element.

As a conventional technique for protecting against excessive input, there is an "optical surge-compatible optical receiver" described in Japanese Patent Application Laid-Open No. 09-31618. However, this invention protects a light receiving element in an optical transmission system. The purpose and the configuration of the present invention are different from those of the present invention.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of a relatively short distance (several meters to several hundreds of meters) such as a wireless LAN and wireless communication of audio signals and video signals. ), And in a type of communication in which a user moves within the range (mobile communication), a reception amplifier circuit capable of preventing destruction due to an excessive input to an amplification element such as a HEMT used as a reception amplifier. It is another object of the present invention to provide a method for protecting an amplification element of a reception amplification circuit.

[0011]

In order to achieve the above object, according to the present invention, a receiving means for receiving a signal by wireless communication, an amplifying means for amplifying a received signal received by the receiving means, Biasing means for generating a bias to be applied to the amplifying means; branching means for branching a received signal to be input to the amplifying means; and a direct current proportional to an average input level per predetermined time by receiving the received signal branched by the branching means A detection means for generating a detection voltage and a detection voltage output from the detection means are input, and the detection voltage is compared with a predetermined threshold voltage set to be equal to or less than a maximum allowable power of an amplification element constituting the amplification means. A comparison means for outputting a comparison result signal based on whether the detection voltage exceeds a threshold voltage, and a comparison result signal output from the comparison means, wherein the comparison result signal is When a signal indicating that the pressure exceeds the threshold voltage, OFF the power supply to the biasing means
And a bias ON / OFF means for turning on a signal indicating that the detection voltage is equal to or lower than the threshold voltage.

According to a second aspect of the present invention, in the first aspect of the present invention, the detecting means amplifies the received signal branched by the branching means to a value necessary and sufficient for subsequent processing. A diode for generating a DC voltage by inputting the reception signal amplified by the one amplifier circuit, and a second amplifier circuit for amplifying the DC voltage generated by the diode to a value necessary and sufficient for subsequent processing. And

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
According to a third aspect of the present invention, in the third aspect, the comparing means outputs, as the comparison result signal, an L level when the detection voltage exceeds the threshold voltage, and outputs an H level when the detection voltage does not exceed the threshold voltage, or On the other hand, when the threshold value is exceeded, an H level is output, and when the threshold value is not exceeded, an L level is output. It is characterized by having a hysteresis characteristic in which two different values are set for a reference value for changing from the L level to the H level.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the comparison means inputs the detection voltage output from the detection means, and controls the detection voltage and the amplification means. A comparator that compares a predetermined threshold voltage set to be equal to or less than the maximum allowable power of the constituent amplifying element, and outputs a comparison result signal based on whether the detection voltage exceeds the threshold voltage; and And a buffer for removing the influence from the circuit at the subsequent stage.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the comparing means includes a detecting voltage output from the detecting means and a maximum value of an amplifying element constituting the amplifying means. A comparator that compares a predetermined threshold voltage set to be equal to or lower than the allowable power and outputs a comparison result signal based on whether the detection voltage exceeds the threshold voltage, and is connected to the comparator, And an inverter for inputting the output comparison result signal and outputting it in the opposite phase.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the inverter is configured using an element having an open collector or an open drain output.

The invention according to claim 7 is the invention according to claim 5 or 6.
The invention described in the above description is further characterized by further comprising an excessive input display means for notifying a user whether or not the level of the received signal exceeds a predetermined threshold voltage by using an output signal of the inverter.

The invention of claim 8 is the invention according to any one of claims 1 to 7, wherein the bias ON / O is provided.
The FF means is characterized in that when a signal indicating that the detection voltage has exceeded the threshold voltage is input from the comparing means, the power supply to the bias means is cut off.

According to a ninth aspect of the present invention, there is provided the invention as set forth in any one of the first to seventh aspects, wherein the bias ON / O
The FF means is characterized in that, when a signal indicating that the detection voltage exceeds the threshold voltage is input from the comparing means, the power supply to the entire apparatus is cut off.

According to a tenth aspect of the present invention, in the eighth aspect, a switch for restarting power supply to the bias means interrupted by the bias on / off means is further provided.

[0021] According to an eleventh aspect of the present invention, there is provided a receiving step of receiving a signal by wireless communication, a branching step of branching the received signal received in the receiving step, and a receiving signal branched in the branching step. A detection step of converting to a DC detection voltage proportional to the average input level per time;
The detection voltage generated in the detection step and a predetermined threshold voltage set to be equal to or less than the maximum allowable power of the amplification element constituting the amplification circuit are compared, based on whether the detection voltage exceeds the threshold voltage, A comparison step of outputting a comparison result signal; and, if the comparison result signal is a signal indicating that the detection voltage is equal to or lower than the threshold voltage, according to the comparison result signal output in the comparison step, a bias voltage applied to the amplifier circuit. And a bias ON / OFF step of turning on the power supply to the bias circuit that generates the signal, and turning off the signal when the signal indicates that the threshold voltage is exceeded.

According to a twelfth aspect of the present invention, in the invention of the eleventh aspect, the detecting step amplifies the received signal branched in the branching step to a value necessary and sufficient for subsequent processing, and converts the amplified received signal. It is characterized in that a DC voltage is generated by detection, and the generated DC voltage is amplified to a value necessary and sufficient for subsequent processing.

According to a thirteenth aspect of the present invention, in the invention of the eleventh or twelfth aspect, the comparing step comprises: as a comparison result signal, when the detection voltage exceeds the threshold voltage, when the detection voltage is at the L level; H level is output, or conversely, when it is exceeded, H level is output, when it is not exceeded, L level is output, and the threshold voltage is set as a reference for changing the comparison result signal from H level to L level. And a reference value for changing the comparison result signal from the L level to the H level.

According to a fourteenth aspect of the present invention, in the invention according to any one of the eleventh to thirteenth aspects, in the comparing step, a comparison result signal is input to an output to remove an influence from a subsequent circuit. It is characterized by using a shock absorber.

According to a fifteenth aspect of the present invention, in the invention according to any one of the eleventh to thirteenth aspects, the comparing step uses an inverter that outputs the comparison result signal in the opposite phase as the output. Features.

According to a sixteenth aspect of the present invention, in the invention of the fifteenth aspect, the comparing step uses an inverter configured using an element having an open collector or open drain output.

According to a seventeenth aspect of the present invention, in the invention of the fifteenth or sixteenth aspect, the user is notified whether or not the level of the received signal exceeds a predetermined threshold voltage by using the output signal of the inverter. An excessive input notification step is further provided.

[0028] The invention according to claim 18 is a receiving step of receiving a signal by wireless communication, a branching step of branching the received signal received in the receiving step, and a receiving signal branched in the branching step, by converting the received signal into a predetermined received signal. A detection step of converting to a DC detection voltage proportional to the average input level per time;
The detection voltage generated in the detection step is compared with a predetermined threshold voltage that is set to be equal to or less than the maximum allowable power of the amplification element included in the amplification circuit, and based on whether the detection voltage exceeds the threshold voltage. A comparison step of outputting a comparison result signal, and applying the comparison result signal to the amplifier circuit if the comparison result signal is a signal indicating that the detection voltage exceeds the threshold voltage according to the comparison result signal output in the comparison step. And a bias OFF step of interrupting power supply to a bias circuit for generating a bias voltage.

According to a nineteenth aspect of the present invention, there is provided a receiving step of receiving a signal by wireless communication, a branching step of branching the received signal received in the receiving step, and a receiving signal branched in the branching step. A detection step of converting to a DC detection voltage proportional to the average input level per time;
The detection voltage generated in the detection step is compared with a predetermined threshold voltage that is set to be equal to or less than the maximum allowable power of the amplification element included in the amplification circuit, and based on whether the detection voltage exceeds the threshold voltage. A comparison step of outputting a comparison result signal, and according to the comparison result signal output in the comparison step,
When the comparison result signal is a signal indicating that the detection voltage exceeds the threshold voltage, a main power OFF step of shutting off power supply to the entire reception amplification apparatus is provided.

[0030]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a reception amplification device according to an embodiment of the present invention. The receiving antenna 1 receives a radio signal and converts it into an electric signal. The received signal is band-limited by the band-pass filter 2, and is input to the first-stage amplifier circuit 8 via the branch circuit 3. The received signal amplified through the first-stage amplifier circuit 8 and the next-stage amplifier circuit 9 is output to the mixer 12 and the like.

A bias circuit 10 is connected to the amplifier circuits 8 and 9.
A bias voltage is applied via and. The amplification circuits 8 and 9 use HEMT or the like as an amplification element. In addition, although the amplifier circuits can be connected in multiple stages, the present embodiment has been described taking a two-stage connection as an example.

An object of the present invention is to control the bias voltage in accordance with the level of the received signal input to the amplifier circuits 8 and 9, thereby preventing the destruction of the amplifier element due to an excessive input. For this purpose, an amplifying element protecting means for detecting a received signal and turning on / off a bias according to the level of the signal is provided.

The amplification element protection circuit 100 includes a branch circuit 3,
It comprises an amplification circuit 4, a detection circuit 5, a comparison circuit 6, and a bias ON / OFF circuit 7.

The branch circuit 3 is composed of a coupler or the like, and branches the main signal. The amplifying circuit 4 amplifies the received signal branched by the branch circuit 3 for processing at the next stage.
The detection circuit 5 receives the reception signal amplified by the amplification circuit 4 and generates a DC detection voltage approximately proportional to the input level of the reception signal.

The comparison circuit 6 compares the DC detection voltage output from the detection circuit 5 with a predetermined threshold voltage, and determines whether or not the voltage exceeds (= over: excessive input) or not (= norm).
al: output a signal voltage of H (High) level or L (Low) level based on the normal range. Input level norm
Which logic of H or L corresponds to al depends on the configuration. Also, it is based on a logical correspondence with a bias ON / OFF circuit 7 described later. The threshold voltage is set to a certain value that is equal to or less than the allowable input power of the amplification elements constituting amplification circuits 8 and 9.

The bias ON / OFF circuit 7 includes a switch for turning ON / OFF the power supply to the bias circuits 10 and 11 according to the output logic of the comparison circuit 6. In this embodiment, the switch is set to ON when the input voltage is 0 V and OFF when the input voltage is 5 V.

FIG. 2 is a diagram showing an example of the configuration of the detection circuit 5. As shown in FIG. The detection circuit 5 detects the high-frequency reception signal amplified by the amplification circuit 4 and generates a DC voltage.
1 and an amplifier 5 which amplifies this DC voltage to a value sufficient for the comparison processing in the comparison circuit 6 and outputs it as a detection circuit output 53.
2 and the like. The output voltage 53 of the detection circuit is desirably about の of the power supply voltage of the comparator 63.

FIG. 3 is a diagram showing an example of the configuration of the comparison circuit 6. The comparison circuit 6 compares the output 53 of the detection circuit with the threshold (threshold) voltage 61 to obtain about 0 V when the input 53 exceeds the threshold (over), and when the input power is within the normal range ( a comparator 63 (comparator) that outputs about 5 V as a comparator output 62 during normal operation, and an inverter 64 that inverts the phase of the comparator output 62 and outputs an inverted output 602.
(Inverter).

The inverter 64 has a logical correspondence with the bias ON / OFF circuit 7. In addition, the inverter 64
Also has a buffer function with the bias ON / OFF circuit 7. A configuration is also conceivable in which the input level is notified to the user using the inverter output 62.

In order to prevent the comparison result from becoming unstable when the detection circuit output voltage 53 very close to the threshold voltage 61 is generated, the comparison circuit 6 may have a hysteresis characteristic. Specifically, the output of the comparator 63 is set to H
A threshold voltage V _{TH (HIGH)} for switching from (5 V: normal) to L (0 V: over) and a threshold voltage V for switching from L to H
Sets a high / low binary threshold voltage different from _{TH (LOW)} .

The threshold voltage 61 is set by an RV (variable resistor) 65 and is determined by the following equations (1) to (3). _{V REF = R67 / (R67 +} RV65) × 5 ····· formula _{(1) V TH (HIGH)} = V REF + R66 / (R66 + R68 + R69) × (5-V REF) ····· formula (2) V _{TH (LOW) = V REF -R66 /} (R66 + R68) × V REF ····· formula _{(3) V TH (HIGH)} : the comparator output 62 is switched from about 5V to about 0V threshold voltage 61 V _{TH (LOW)} Threshold voltage 61 for switching comparator output 62 from about 0 V to about 5 V

FIG. 4 is a diagram showing an example of the configuration of the bias ON / OFF circuit 7. Bias ON / OFF circuit 7
Turns ON / OFF the power supply to the bias circuits 10 and 11 according to the input 75 which is the output from the comparison circuit 6.
It comprises switches 73 and 74 for controlling.

It is to be noted that a configuration in which the bias ON / OFF circuit 7 is provided outside the apparatus so that the user can operate it (or a configuration in which the bias is turned ON / OFF by another switch provided outside) is also conceivable. . In this case, the same operation is realized by passing the output from the comparison circuit 6 to an external device in which the bias ON / OFF circuit 7 is installed. If the purpose is not to automatically recover from the bias OFF at the time of excessive input, a configuration in which power supply to the bias circuit is cut off when excessive input is detected, or a configuration in which power supply to the entire device is cut off is also considered. In this case, the user performs a return process by operating a switch.

The band pass filter 2, the branch circuit 3, the amplifier circuits 8 and 9, the bias circuits 10 and 11 of FIG.
Is well known to those skilled in the art, and is not directly related to the present invention, and thus detailed description thereof is omitted.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS. A reception signal from the reception antenna 1 passes through the band-pass filter 2 and is branched via the branch circuit 3, and the main signal is input to the amplification circuit 8. Further, the branch signal branched by the branch circuit 3 is amplified by the amplifier circuit 4 to a power that can be detected by the detector circuit 5 and then input to the detector circuit 5.

The branch signal input to the detection circuit 5 shown in FIG. 2 is detected by the diode 51 and converted into a DC voltage signal. Thereafter, the voltage is amplified by the amplifier 52 to a voltage sufficient for the comparison operation in the comparison circuit 6, and is output as a detection circuit output voltage 53. The detection circuit output voltage 53 is
Is input to

The detection circuit output voltage 53 input to the comparison circuit 6 shown in FIG. 3 is compared in a comparator 63 with a preset threshold voltage 61. When the input power is within the normal range, the detection circuit output voltage 53 <the threshold voltage 61, and the comparator output voltage 62 is about 5V. If the input power exceeds the specified maximum allowable power, the detection circuit output voltage 53
> The threshold voltage 61, and the comparator output voltage 62 becomes about 0V.

The comparator output voltage 62 is input to the inverter 64. The comparator output voltage 62 input to the inverter 64
Are inverted in phase and output as an inverter output voltage 602. The inverter output voltage 602 is about 0 V when the input voltage is within the normal range and about 5 V when the input power exceeds the threshold voltage, contrary to the comparator output voltage 62.

If the bias ON / OFF circuit 7 is configured to receive the comparator output 62 as an input, 5
In case of V, switch ON, in case of 0V, switch O
A logical correspondence to FF is taken. In the present embodiment, since the configuration is such that the inverter output 62 is input, a logical correspondence that the switch is OFF at 5 V and the switch is ON at 0 V is adopted.

When a normal inverter is used, the output voltage of the inverter is approximately 0 V at the time of power-on, regardless of the value of the comparator output voltage 62. As a result, when the power is turned on in a state where the input power exceeds the specified allowable power, excessive input is applied to the amplifier circuits 8 and 9 if the switch is ON at 0 V. In order to prevent such an operation, the inverter output voltage 6
Inverter 64 has an open collector (or open drain) so that 02 becomes approximately 5 V at power-on.
A configuration using an output element is conceivable.

As described above, when the input power is within the normal range, the output of the comparison circuit 6 (= the inverter output voltage 60
As 2), about 0 V is output, and when the input is excessive, about 5 V is output and input to the bias ON / OFF circuit 7.

When about 5 V is input to the input 75 of the bias ON / OFF circuit 7 shown in FIG. 4 (= excessive input)
The power supplies 71 and 72 to the bias circuits 10 and 11 are turned off, and the bias
1, 82 and 91, 92 are turned off. As a result, the amplifying elements 83 and 93 in the amplifying circuits 8 and 9 are protected.

Thereafter, when approximately 0 V is input to the input 75 as the output from the comparison circuit 6 (= when the input power returns within the normal range), the power supplies 71 and 72 to the bias circuits 10 and 11 are turned off. Is turned on, and the amplifier circuits 8 and 9
Biases 81, 82 and 91, 92 are turned on. As a result, the amplifier circuits 8 and 9 return to the normal operation.

The configuration and operation of the embodiment of the present invention have been described above. In the above embodiment, the amplification circuit 8
Although HEMTs are used as and 9, a circuit using another transistor, a circuit using an IC, or the like may be used. Also,
The inverter 64 in the comparison circuit 6 becomes unnecessary according to the logic of the bias ON / OFF circuit 7. In this case, the inverter 64
It is good to provide a shock absorber at the position. The switches 73 and 74 may be any switches such as an IC switch and an FET switch.

The above-described embodiment is an example of a preferred embodiment of the present invention, and the present invention is not limited to the embodiment, and various modifications may be made without departing from the scope of the invention. It is possible.

[0057]

As is apparent from the above description, according to the first aspect of the present invention, since the level of the signal input to the amplifier circuit is constantly monitored (detected), the moving transmitter If the input power exceeds a predetermined threshold voltage due to a device approaching the receiving device or erroneously emitting high transmission output power near the receiving device, the supply of the bias voltage to the amplifier circuit is instantaneously shut off. Is done. Thus, it is possible to prevent the amplifying element in the amplifying circuit from being destroyed due to excessive input. Further, when the input level returns to within the normal range, for example, when the moving sender moves away from the receiving device, the supply of the bias voltage to the amplifier circuit is immediately restarted, and the amplifier circuit can return to the steady state.

According to the third aspect of the present invention, by providing the comparison circuit with a hysteresis characteristic, it is possible to prevent the comparison result from becoming unstable when a detection voltage very close to the threshold voltage is generated. it can.

According to the sixth aspect of the present invention, since the bias supply is turned off when the power supply rises, it is possible to protect the amplifying element even when the power supply is started while the input power exceeds the specified allowable power. Can be.

According to the seventh aspect of the present invention, the user:
It is possible to know whether the received signal level is within a normal range or exceeds a prescribed maximum allowable input level.

According to the eighth aspect of the present invention, it is possible to employ an amplifying element protection method of cutting off the bias voltage thereafter when the automatic recovery from the bias OFF is not intended at the time of excessive input.

According to the ninth aspect of the present invention, there is provided a method for protecting an amplifying element by shutting off power supply to an entire receiving amplifier when an excessive input is not intended for automatic recovery from a bias OFF. Can be taken.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a reception amplification device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a configuration of a detection circuit 5.

FIG. 3 is a diagram illustrating an example of a configuration of a comparison circuit 6;

FIG. 4 is a diagram illustrating an example of a configuration of a bias ON / OFF circuit 7;

FIG. 5 is a block diagram illustrating a configuration of a conventional reception amplification device.

[Explanation of symbols]

 Reference Signs List 1 reception antenna 2 band-pass filter 3 branch circuit 4 amplification circuit 5 detection circuit 6 comparison circuit 7 bias ON / OFF circuit 8, 9 amplification circuit 10, 11 bias circuit 12 mixer 100 amplification element protection circuit 51 diode 52 amplifier 53 detection circuit output (Comparator input) 61 Threshold voltage 62 Comparator output voltage 63 Comparator 64 Inverter 65 Variable resistor 66, 67, 68, 69 Resistance 601 Load resistance 602 Inverter output voltage 71, 72 Bias power supply 73, 74 Switch 75 Comparison Circuit output 81, 82, 91, 92 Bias voltage 83, 93 Amplifying element

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 5J091 AA01 AA51 CA57 CA81 FA10 FA18 FP01 GP06 HA09 HA12 HA19 HA25 HA26 HA29 HA38 HA39 KA04 KA12 KA17 KA38 KA44 KA48 KA55 MA08 MA24 SA01 SA13 TA01 5J092 AA12 CA18 HA09 HA19 HA25 HA26 HA29 HA38 HA39 KA04 KA12 KA17 KA38 KA44 KA48 KA55 MA08 MA24 SA01 SA13 TA01 VL07 5J100 JA01 LA00 LA09 LA10 QA00 QA04 SA02 5K062 AA06 AA09 AB15 AD04 AD08 AE04 AE05 AF01 AG03 BA01 BC03 BD03

Claims (19)

[Claims] 1. A receiving means for receiving a signal by wireless communication, an amplifying means for amplifying a received signal received by the receiving means, a biasing means for generating a bias applied to the amplifying means, and an input to the amplifying means A branching means for branching the received signal, a detecting means for inputting the received signal branched by the branching means and generating a DC detection voltage proportional to an average input level per predetermined time, and an output from the detecting means. The detected voltage is inputted, and the detected voltage is compared with a predetermined threshold voltage that is set to be equal to or less than a maximum allowable power of an amplifying element constituting the amplifying unit, and the detected voltage exceeds the threshold voltage. Comparing means for outputting a comparison result signal based on whether or not the comparison result signal is output from the comparing means;
When the comparison result signal is a signal indicating that the detection voltage exceeds the threshold voltage, power supply to the bias unit is turned off, and a signal indicating that the detection voltage is equal to or lower than the threshold voltage is output. ON, bias ON / O
And FF means. 2. A first amplification circuit for amplifying the reception signal branched by the branching unit to a value necessary and sufficient for subsequent processing, the detection unit comprising: a first amplification circuit configured to amplify the reception signal amplified by the first amplification circuit; And a second amplifier circuit for amplifying the DC voltage generated by the diode to a value necessary and sufficient for subsequent processing. The receiving amplifying device as described in the above. 3. The comparison means outputs, as the comparison result signal, an L level when the detection voltage exceeds the threshold voltage, and outputs an H level when the detection voltage does not exceed the threshold voltage, or conversely, outputs the H level. The threshold voltage is output when the comparison result signal is changed from the H level to the L level. 2 that is different from the reference value for changing from the L level to the H level.
3. The reception amplification device according to claim 1, wherein the reception amplification device has a hysteresis characteristic set to one of two values. 4. The comparison means receives the detection voltage output from the detection means, and outputs the detection voltage and a predetermined threshold voltage set to be equal to or less than a maximum allowable power of an amplification element constituting the amplification means. And
A comparator that outputs a comparison result signal based on whether or not the detection voltage exceeds the threshold voltage; and a buffer that is connected to the comparator and that removes an influence from a subsequent circuit. The reception amplification device according to any one of claims 1 to 3, characterized in that: 5. The comparing means compares the detected voltage output from the detecting means with a predetermined threshold voltage set to be equal to or less than a maximum allowable power of an amplifying element constituting the amplifying means. A comparator that outputs a comparison result signal based on whether or not the detection voltage exceeds the threshold voltage; and a comparator that is connected to the comparator and that receives the comparison result signal output from the comparator and reverses the phase. The receiving amplifier according to any one of claims 1 to 3, further comprising: an inverter that outputs the received signal. 6. The reception amplifying device according to claim 5, wherein said inverter is configured using an element having an open collector or an open drain output. 7. An excessive input display means for using a signal output from the inverter to notify a user whether or not the level of the received signal exceeds the predetermined threshold voltage. Item 7. The reception amplification device according to item 5 or 6. 8. The bias on / off means, when a signal indicating that the detection voltage exceeds the threshold voltage is input from the comparison means, shuts off power supply to the bias means. The reception amplification device according to claim 1, wherein: 9. The bias ON / OFF means, when a signal indicating that the detection voltage exceeds the threshold voltage is input from the comparison means, shuts off power supply to the entire apparatus. The receiving amplifier circuit according to any one of claims 1 to 7, wherein: 10. The reception amplifying device according to claim 8, further comprising a switch for resuming power supply to said bias means, which has been cut off by said bias ON / OFF means. 11. A receiving step of receiving a signal by wireless communication, a branching step of branching the received signal received in the receiving step, and a step of dividing the received signal branched in the branching step for a predetermined time of the received signal. A detection step of converting to a DC detection voltage proportional to the average input level of the detection voltage, the detection voltage generated in the detection step, a predetermined threshold voltage set to be equal to or less than the maximum allowable power of the amplification element constituting the amplification circuit, Comparing the detected voltage exceeds the threshold voltage, and outputting a comparison result signal based on whether or not the detection voltage exceeds the threshold voltage; and comparing the comparison result signal in response to the comparison result signal output in the comparison step. Is a signal indicating that the detection voltage is equal to or lower than the threshold voltage, the power supply to a bias circuit that generates a bias voltage to be applied to the amplifier circuit is turned on. If a signal indicating that the component exceeds the threshold voltage, the amplifier element protection method of receiving amplifying device, characterized in that it comprises a bias ON / OFF process of OFF, the. 12. The detecting step includes: amplifying the reception signal branched in the branching step to a value necessary and sufficient for subsequent processing; detecting the amplified reception signal to generate a DC voltage; The method according to claim 11, wherein the applied DC voltage is amplified to a value necessary and sufficient for subsequent processing. 13. The comparing step outputs, as the comparison result signal, an L level when the detection voltage exceeds the threshold voltage, and outputs an H level when the detection voltage does not exceed the threshold voltage, or conversely, outputs the H level. If the threshold value is not exceeded, an H level is output. If not, an L level is output. The threshold voltage is a reference value for changing the comparison result signal from the H level to the L level, and the comparison result signal is changed from the L level to the H level. 13. The method according to claim 11, wherein the method has a hysteresis characteristic of setting two values different from a reference value for changing the level. 14. The method according to claim 11, wherein the comparing step uses a buffer that receives the comparison result signal as an output and removes an influence from a subsequent circuit. The method for protecting an amplifying element of a reception amplifying device as described in the above. 15. The receiving amplifying apparatus according to claim 11, wherein the comparing step uses an inverter that outputs the comparison result signal in an inverted phase for output. Amplifying element protection method. 16. The method according to claim 15, wherein the comparing step uses an inverter configured using an element having an open collector or an open drain output. 17. An excessive input notification step of notifying a user whether or not the level of the reception signal exceeds the predetermined threshold voltage, using an output signal of the inverter. 17. The method for protecting an amplification element of a reception amplification device according to claim 15 or 16. 18. A receiving step of receiving a signal by wireless communication, a branching step of branching a received signal received in the receiving step, and a step of dividing the received signal branched in the branching step by a predetermined time of the received signal. A detection step of converting to a DC detection voltage proportional to the average input level, the detection voltage generated in the detection step, a predetermined threshold voltage set to be equal to or less than a maximum allowable power of an amplification element constituting an amplification circuit, Comparing the detected voltage exceeds the threshold voltage, and outputting a comparison result signal based on whether or not the detection voltage exceeds the threshold voltage; and comparing the comparison result signal in response to the comparison result signal output in the comparison step. Is a signal indicating that the detection voltage exceeds the threshold voltage, power supply to a bias circuit for generating a bias voltage to be applied to the amplifier circuit is cut off. Having a bias OFF step, the amplification element protection method of receiving amplifying device according to claim. 19. A receiving step of receiving a signal by wireless communication; a branching step of branching the received signal received in the receiving step; A detection step of converting the detection voltage into a DC detection voltage proportional to the average input level of the detection circuit, the detection voltage generated in the detection step, and a predetermined threshold voltage set to be equal to or less than a maximum allowable power of an amplification element included in the amplification circuit. A comparison step of outputting a comparison result signal based on whether or not the detection voltage exceeds the threshold voltage; and comparing the comparison result signal in accordance with the comparison result signal output in the comparison step. When the result signal is a signal indicating that the detection voltage exceeds the threshold voltage, a main power OFF step of shutting off power supply to the entire reception amplification apparatus. , Amplifying element protecting method of the receiving amplifier circuit according to claim.