JP3866683B2 - Receiver for return device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a receiver used for a sending back device, and more particularly to a technique for switching the reception frequency when the receiver exceeds a predetermined communication area.
[0002]
[Prior art]
For example, an audio signal communication device called a sending back device or a sending back wireless system is used for communication between a director in a sub-adjustment room in a television station and performers and workers in a studio.
[0003]
Conventionally known audio signal communication devices of this type include those that receive radio waves transmitted from a fixed transmitter of frequency modulation system with a moving receiver of the same system. In this case, in the receiver, the frequency of the transmitter and the receiver is matched by manually switching the frequency using the PLL synthesizer method.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-55642
[Problems to be solved by the invention]
By the way, in the conventional sending back apparatus, when the radio wave emitted from the fixed transmitter is exceeded (reception area), the user of the moving receiver receives the reception range by the deterioration of the clarity of the received audio signal. It was judged that the frequency was exceeded, and the frequency received manually was changed.
[0006]
For this reason, a user who has a receiver needs to manually switch the frequency every time the reception area is exceeded, which is troublesome. Further, in the manual selection, when there are a plurality of next reception areas, there is a problem that the user may select the wrong area.
[0007]
Furthermore, the manual selection is unavoidable that the sound is interrupted when the switch is switched, and in order to solve this problem, a plurality of receiving devices that are always turned on are prepared. It is conceivable to receive while switching, but in this case, a new problem of increasing power consumption occurs.
[0008]
Further, as described in Patent Document 1, a radio receiver that searches a reception band, selects a reception frequency that is equal to or higher than a certain level, and stores the selected reception frequency information as a plurality of preset frequencies is also known. However, they did not automatically switch to the most sensitive frequency when the reception area was exceeded. For this reason, it is difficult to apply such technology to a sending-back device that frequently moves across the reception area, such as a television station, and with such technology it is not possible to cut sound and reduce power consumption. could not.
[0009]
The present invention has been proposed to solve the above-described problems of the prior art, and its purpose is to detect a decrease in reception sensitivity when the receiver exceeds a predetermined reception area. Thus, it is an object of the present invention to provide a receiver for a return device that eliminates manual frequency switching by automatically switching to a frequency in an area with the highest reception sensitivity that can be received by the receiver.
[0010]
Another object of the present invention is to eliminate voice interruptions and suppress an increase in power consumption in a receiver that automatically switches frequencies according to reception sensitivity.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is used in a sending back device for communication between a broadcasting station and a broadcast site worker, and is arranged in different areas and transmits a plurality of different predetermined frequencies. A receiver for a sending back device that receives radio waves from a transmitter, wherein the receiving side and the standby side receive the plurality of frequencies to obtain substantially the same audio signal, and the receiving side and the standby side Receiving-side and standby-side field strength detectors for detecting the electric field strength of the frequency received at the receiving unit on the side, and power-control on the receiving side and the standby side for controlling the supply of power to the receiving units on the receiving side and the standby side An audio signal control unit that switches the supply of power from the reception unit on the reception side to the reception unit on the standby side, and a control device that controls switching processing from the reception side to the standby side by the audio signal control unit, Comprising the control device When the reception sensitivity of the reception-side electric field strength detector is equal to or greater than a certain threshold, the power-supply control unit is turned on only to the reception-side reception unit to detect the reception-side electric field strength. When the reception sensitivity of the detector falls below a certain threshold value, the power supply control unit is powered on to the standby side reception unit, the standby side reception unit starts reception, and the standby side field strength detection The detector detects the electric field strength of the plurality of frequencies received by the standby-side receiving unit, determines the maximum-intensity frequency based on this, outputs the maximum-intensity frequency to the standby-side receiving unit, and waits. The reception unit on the side starts reception, the reception unit on the standby side starts reception, and then the power supply control unit cuts off the power on the reception side.
[0012]
According to the first aspect of the invention having such a configuration, when the reception sensitivity of the receiving unit on the receiving side is lowered, the receiving unit on the standby side is turned on and the optimum frequency is searched while continuing reception. When the optimum reception frequency is received on the standby side, the voice output is switched from the reception side to the standby side, so that the interruption of voice during the search for the optimum frequency can be resolved. In addition, after the reception is switched to the reception unit on the standby side, it is possible to save power by stopping the power-on to the reception unit on the reception side so far.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
(1) First Embodiment FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a functional block diagram of a receiver according to the present embodiment, and FIG. 2 is its control software. It is a flowchart of.
[0014]
(1-1) Configuration of the First Embodiment As shown in FIG. 1, the receiver of the present embodiment is similar to a receiving unit of a known FM receiver in that the receiving antenna 1 and the high-frequency amplification from the radio wave input side. A circuit 2, a tuning phase locked loop circuit 3, an intermediate frequency circuit 4, and an FM detection circuit 5 are provided. On the output side of the receiving unit, a low frequency amplifier circuit 6, a squelch circuit 7 and an output speaker 8 for processing the audio signal obtained by the receiving unit are provided. Further, a control device 9 is provided for controlling each of these circuits and each circuit unique to the present invention, which will be described later, and this control device 9 stores a control CPU 91 and its driving software and processing data. A memory 92 is provided. The control device 9 is provided with an input device 93 such as a channel selection switch and a keyboard, and a display 94 such as a liquid crystal display and an LED.
[0015]
The high-frequency amplifier circuit 2 includes a band-pass filter 21 for input, a high-frequency amplifier 22, and a band-pass filter 23 for limiting the output band, and an output of the band-pass filter 23 forms a phase-locked loop circuit 3. 34.
[0016]
The phase-locked loop circuit 3 outputs a local oscillation signal having a predetermined frequency set for channel selection. As an oscillation frequency selection circuit, a PLL (phase-locked loop) controller 31, a loop filter 32, A VCO (voltage controlled oscillator) 33 is provided. The PLL controller 31 receives a channel selection command from the control CPU 91, and based on the channel selection command, a specified frequency can be selected from a predetermined number of channels (for example, four frequencies). ing.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
(1) First Embodiment FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a functional block diagram of a receiver for a return device according to the present embodiment. FIG. It is a flowchart of the software for control.
[0018]
(1-1) Configuration of the First Embodiment As shown in FIG. 1, the receiver for the return device according to the present embodiment is similar to the receiving unit of a known FM receiver from the input side of the radio wave from the receiving antenna 1. A high-frequency amplifier circuit 2, a phase-locked loop circuit 3 for channel selection, an intermediate frequency circuit 4, and an FM detection circuit 5. On the output side of the receiving unit, a low frequency amplifier circuit 6, a squelch circuit 7 and an output speaker 8 for processing the audio signal obtained by the receiving unit are provided. Further, a control device 9 is provided for controlling each of these circuits and each circuit unique to the present invention, which will be described later, and this control device 9 stores a control CPU 91 and its driving software and processing data. A memory 92 is provided. The control device 9 is provided with an input device 93 such as a channel selection switch and a keyboard, and a display 94 such as a liquid crystal display and an LED.
[0019]
In the receiver of the present embodiment having the basic configuration as described above, the present invention is provided with a characteristic configuration as described below.
[0020]
The output of the squelch switch circuit 72 is input to the control CPU 91. The control CPU 91 is predetermined when the squelch switch circuit 72 is activated and the audio signal amplifier 63 stops outputting for a predetermined time. All the frequencies of each channel are set to be sequentially output to the PLL controller 31 as channel selection frequencies.
[0021]
An electric field strength detector 101 for a received signal is connected to the output side of the linear amplifier 45 of the intermediate frequency circuit 4, and voltage information that is a detection value of the electric field strength detector 101 is input to the control CPU 91. The voltage information of each channel obtained by the electric field strength detector 101 is accumulated in the state of A / D conversion in the control CPU 91, and it is compared with which channel the electric field strength is high. Further, as a result of the comparison, the control CPU 91 is set to output the highest frequency of the electric field strength to the PLL controller 31 as the channel selection frequency.
[0022]
(1-2) Operation of the First Embodiment Next, the operation of the present embodiment will be described using the flowchart of FIG.
First, in the usage state of the receiver, the device control CPU 91 determines whether the output from the squelch switch circuit 72 is on or off (step 201). As described above, the squelch switch circuit 72 controls the on / off of the audio signal amplifier 63, and if the receiver exceeds the range (reception area) where radio waves can be received, the clarity of the received audio signal deteriorates. The switch circuit 72 turns off the audio signal amplifier 63 to close the squelch, and interrupts the output from the speaker 8.
[0023]
With respect to the receiver for the return device of the present embodiment having the basic configuration as described above, the present invention is provided with a characteristic configuration as described below.
[0024]
When the squelch is opened again within a predetermined time, that is, when the squelch off signal from the squelch switch circuit 72 does not continue for a predetermined time or longer (NO in step 204), the original reception state is restored. On the other hand, when the state where the squelch is closed continues for a certain period of time (YES in step 204), the control CPU 91 causes the display unit 94 to display during radio wave search (step 205).
[0025]
When the squelch is closed and the reception sensitivity decreases as described above, it is generally considered that the receiver has transcended its reception area, but in this case, it is immediately known which reception area it has moved to. do not do. Therefore, in the present embodiment, the control CPU 91 sequentially outputs the frequencies of all the channels to be received to the PLL controller 31 at regular intervals (step 206). When the first channel selection frequency is set in the PLL controller 31, the reception sensitivity for that frequency is changed to the field strength voltage information from the field strength detector 101 connected to the linear amplifier 45 of the intermediate frequency circuit 4. (Step 207), this voltage information is A / D converted (step 208) and stored as numerical data in a memory on the control device 9 or the like.
[0026]
The acquisition of voltage information as described above is repeated for all frequencies, and when data acquisition is completed for all frequencies (YES in step 209), the process proceeds to the next step 210, and if not acquired (NO in step 209) ), The process returns to step 206, and the next frequency to be received is set in the PLL controller 31.
[0027]
If the search for all frequencies is confirmed in this way, the field strengths of all the acquired frequencies are compared (step 210), and the frequency with the highest field strength is set in the PLL controller 31 (step 211). That is, since the frequency with the highest electric field strength can be received, the display during the radio wave search on the display 94 is stopped (step 212).
[0028]
As described above, in this embodiment, when the squelch circuit detects that the reception sensitivity has decreased at the frequency being received, the control CPU 91 receives the reception sensitivity for all frequencies that can be received by the receiver. Are sequentially searched and the most sensitive frequency can be selected as a new reception frequency. As a result, even when the receiver exceeds the reception area, it is possible to automatically select the optimum reception frequency without any particular awareness of the user. Or selecting an inappropriate frequency.
[0029]
In the first embodiment, it is determined that the reception sensitivity is lowered based on the output from the squelch switch circuit, and the control CPU 91 sets all reception frequencies in the PLL controller 31 and searches for the optimum frequency. However, without using the squelch switch circuit, the electric field strength voltage information from the electric field strength detector 101 connected to the linear amplifier 45 is always detected, and the optimum frequency is searched when the information drops below a certain value. It is also possible to do this.
[0030]
(2) Second Embodiment Next, a second embodiment of the present invention will be described based on the functional block diagram of FIG. 3 and the flowchart of FIG. In the second embodiment, the combination of the two devices of the first embodiment prevents voice interruption when searching for the optimum frequency, and the power consumption of the two receivers can be switched appropriately. The amount can be reduced.
[0031]
(2-1) Configuration of Second Embodiment As shown in FIG. 3, the receiver of the present embodiment includes a first receiver A and a second receiver connected to the receiving antenna 1 via a distributor 201. It is comprised from the receiving part B. The first receiving unit A and the second receiving unit B include high-frequency amplifier circuits 2A and 2B, tuning phase-locked loop circuits 3A and 3B, intermediate frequency circuits 4A and 4B, and FM detection circuits 5A and 5B, respectively. I have. Also, the linear amplifiers 45A and 45B are provided with electric field intensity detectors 101A and 101B, as in the first embodiment. In addition, about the element which is common in 1st Embodiment in each circuit, description is abbreviate | omitted by attaching | subjecting A and B to the same code | symbol.
[0032]
The output sides of the FM detection circuits 5A and 5B of the reception units A and B are connected to the low frequency amplifier 61 and the low frequency filter 62 of the low frequency amplification circuit 6 via the audio signal control unit 202 that is controlled to be switched by the control CPU 91. And an audio signal amplifier 63. As in the first embodiment, the squelch circuit 7 including the squelch amplifier 71 and the squelch switch circuit 72 is provided, but the output of the squelch switch circuit 72 is not connected to the control CPU 91. That is, in the present embodiment, the squelch circuit 7 is separated from the receiving unit A and the receiving unit B and operates independently, so that it does not affect which receiver the receiver uses to receive. Operation is possible.
[0033]
The control CPU 91 is connected to power control units 203A and 203B provided in the receiving units A and B, respectively. The power supply control units 203A and 203B are devices constituting the receiving units A and B, that is, high-frequency amplifiers 22A and 22B, PLL controllers 31A and 31B, loop filters 32A and 32B, VCOs 33A and 33B, a tuning mixer 34A, 34B, local oscillators (OSC) 42A and 42B, intermediate frequency mixers 43A and 43B, linear amplifiers 45A and 45B, FM detection circuits 5A and 5B, and electric field intensity detectors 101A and 101B are controlled to be turned on / off. .
[0034]
(2-2) Operation of Second Embodiment Next, the operation of the present embodiment will be described with reference to the flowchart of FIG.
First, when the receiving unit A is the voice receiving side and the receiving unit B is the standby side, the electric field strength detector 101A of the receiving unit A detects the electric field strength for the frequency that is constantly being received, and this is used for control. The information is output to the CPU 91, and the control CPU 91 acquires and monitors the voltage information (step 401). When the electric field strength received by the receiver decreases due to the movement of the receiver, the voltage information is sent to the control CPU 91, and the control CPU 91 determines that the decrease in the electric field strength is below a predetermined threshold (step 402). YES), control is passed to the next step 403. If it is equal to or greater than the threshold (NO in step 402), the process returns to step 401 and monitoring is continued.
[0035]
(2-1) Configuration of Second Embodiment As shown in FIG. 3, the receiver for the sending back device of the present embodiment includes a first receiving unit A connected to the receiving antenna 1 via a distributor 201. And a second receiving unit B. The first receiving unit A and the second receiving unit B include high-frequency amplifier circuits 2A and 2B, tuning phase-locked loop circuits 3A and 3B, intermediate frequency circuits 4A and 4B, and FM detection circuits 5A and 5B, respectively. I have. Also, the linear amplifiers 45A and 45B are provided with electric field intensity detectors 101A and 101B, as in the first embodiment. In addition, about the element which is common in 1st Embodiment in each circuit, description is abbreviate | omitted by attaching | subjecting A and B to the same code | symbol.
[0036]
When the power of the receiving unit B is turned on, a display indicating that the radio wave is being searched is displayed on the display 94 (step 405). Thereafter, the receiving unit B searches for the optimum frequency in the same manner as in the first embodiment. The optimum frequency is set in the PLL controller 31B of the receiver B (steps 406 to 411). Thereafter, the display during the radio wave search on the display 94 is stopped. Since these operations are the same as steps 205 to 212 in the first embodiment (step 412), description thereof will be omitted.
[0037]
In this way, since reception at the optimum reception frequency is possible by the reception unit B, the audio signal output switching from the reception unit A that is currently receiving to the reception unit B that is capable of reception of the optimum frequency is performed next. (Step 413). That is, the voice signal control unit 202 cuts off the input from the FM detection circuit 5A of the reception unit A and causes the low frequency amplifier 61 to output the input from the FM detection circuit 5B of the reception unit B according to a command from the control CPU 91. As a result, the speaker 8 outputs an audio signal based on the received signal received at the optimum frequency of the receiving unit B.
[0038]
Subsequently, the control CPU 91 outputs a power supply stop command to the power supply control unit 203A of the reception unit A, and the power supply of each circuit and device constituting the reception unit A is stopped by the power supply control unit 203A (step 414). . As a result, the receiving unit A enters a standby state, and wasteful power consumption is not consumed. In addition, since the power of both the receiving unit A and the receiving unit B is turned on until the switching of the audio signal is completed, there is no inconvenience that the audio is cut off when the receiving unit B searches for the optimum frequency.
[0039]
In this way, after the switching from the receiving unit A to the receiving unit B is completed, the monitoring of the frequency being received by the electric field intensity detector 101B of the receiving unit B is continued, and when the reception sensitivity decreases, Contrary to the above, the power of the receiving unit A in standby is turned on, and the optimum frequency is searched. Then, after the optimum frequency is set in the PLL controller 31A, the audio output and the power source are switched to the receiving unit A (steps 415 to 428). Hereinafter, the optimum reception state is always ensured by repeatedly selecting the optimum frequency and switching the audio output between the receiving unit A and the receiving unit B alternately. Note that steps 415 to 428 indicating the operation after switching to the reception unit B are the same as steps 401 to 414 during reception of the reception unit A, and thus description thereof is omitted.
[0040]
【The invention's effect】
As described above, according to the present invention, when the reception sensitivity is lowered, it is possible to compare all the electric field strengths of all frequencies to be received and set the frequency of the largest electric field strength in the PLL circuit. There is an advantage that switching to a frequency having the highest electric field strength is automatically performed. In addition, when a plurality of receiving units are provided to switch between the frequency and the power source, it is possible to prevent interruption of sound during frequency search or switching while suppressing power consumption.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a receiver for a return device according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the receiver for the return device according to the first embodiment of the present invention.
FIG. 3 is a functional block diagram of a receiver for a return device according to a second embodiment of the present invention.
FIG. 4 is a flowchart showing the operation of the receiver for the return device according to the second embodiment of the present invention.

Claims (1)

A receiver for a return device for receiving a radio wave from a plurality of transmitters arranged in different areas and transmitting different predetermined frequencies, which is used for a return device for communication between a broadcasting station and a broadcast site worker. A receiving side for receiving the plurality of frequencies to obtain substantially the same audio signal; a receiving side for receiving the plurality of frequencies; and a receiving side for detecting the electric field strength of the frequency received by the receiving unit for the receiving side and the standby side A standby-side electric field strength detector, a receiving-side and standby-side power control unit that controls power supply to the receiving-side and standby-side receiving units, and the power-supply from the receiving-side receiving unit to the standby-side An audio signal control unit that switches to the receiving unit, and a control device that controls switching processing from the reception side to the standby side by the audio signal control unit,
  The controller is
  In the case where the reception sensitivity by the reception-side electric field strength detector is equal to or higher than a certain threshold value, the power control unit is allowed to turn on only the reception unit on the reception side,
  When the reception sensitivity of the reception-side electric field strength detector is lower than a certain threshold, the power supply control unit is turned on for the standby-side reception unit, and the standby-side reception unit starts reception, The standby-side electric field strength detector detects the electric field strengths of the plurality of frequencies received by the standby-side receiving unit, and determines a maximum-intensity frequency based on the detected electric-field strengths. Output to the receiver and start reception on the standby receiver,
  A receiver for a feed back device, wherein after the reception unit on the standby side starts reception, the power control unit cuts off the power on the reception side.

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