SU1658406A1 - Device for audio channel testing - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to improve the accuracy and enhance the functionality by increasing the range of measured parameters. The device contains a priority block 1, a low-pass filter 2, a quasi-peak detector 3. an integrator 4, an analog-code converter 5, a statistical signal processing block 6, blocks 7 and 8 of pre-signal processing, a digital timer 9, a clock generator 10, amplifiers 11 and 12 , indication block 13, switches 14-21, quad 22, memory block 23, audio signal detector 24, adder 25, frequency divider 26 and calibrator 27. When the signal decreases below a certain limit, information about this from the output of block 7 goes to the digital inputs timer 9 and block 1. On The output of block 1 generates a signal, which puts the switch 21 in such a state that block 13 receives information about the length of the pause. 1 hp ff, 2 ill. 6 o ate 00 s

Description

The invention relates to radio engineering, specifically to radio broadcasting and television, and can be used to automatically control the level of the audio signal at the input and output of the radio transmitter, the power of the sound transmitter, the length of the pause in the audio signal, the duration of the lack of power, and indirect control of frequency deviation and depth modulation in monaural and stereo broadcasting and the transmission of additional information by the same radio transmitter, and can be used in the design and operation tion.

The purpose of the invention is to improve the accuracy and enhance the functionality by increasing the range of measured parameters.

FIG. 1 shows a structural electrical circuit of the device for controlling the sound channel: FIG. 2 is a structural electrical signal detector circuit.

The device for monitoring the audio channel (Fig. 1) contains a priority block 1, a low-pass filter 2, a quasi-peak detector 3, an integrator 4, an analog-code converter 5, a block b of statistical signal processing, blocks 7 and 8 of tolerant signal processing, a digital timer 9 , clock generator 10, amplifiers 11 and 12, winding unit, switches 14-21, quad 22, memory block 23, audio signal detector 24, adder 25, frequency divider 26, calibrator 27. Audio signal detector 24 contains (Fig. 3 a) attenuator 28, a mixer 29, a band-pass filter 30, amplifiers 31 and 32 pr intermediate frequency, frequency detectors 33-36, amplitude detectors 37 and 38, switches 39-41, low-frequency amplifiers 42-46, block 47 automatic level control, low-pass filters 48 and 49, frequency divider 50 and DC amplifier 51.

The device for monitoring the sound channel works as follows.

The measured signal (e.g., signal A in stereo broadcasting or mono signal) through switch 14 and amplifier 11 is fed to the input of adder 25 with an adjustable transmission coefficient (in stereo mode, the transmission coefficient should be halved). From the output of the adder 25, through the switch 16 and the filter 2, the signal is fed to the input of the quasi-peak detector 3. The detected voltage from which is fed to the input of the integrator 4. From the output of the integrator 4 through the switch 20, the signal goes to the input of the converter 5.

From the output of the converter 5, information is fed to the input of block 6 of statistical signal processing, where, of all the current values of the code characterizing the dynamic signal, only the maximum value during the time interval is recorded. From the output of block 6, information arrives at the input of switch 21 and, if the other monitored parameters are within tolerance (and this is followed by block 1 of priority), it is switched to display unit 13. In this way,

5 measurement of the sound broadcasting level.

At the same time, the information from block 5 is fed to the input of block 7 of the pre-processing signal. In block 7, the digital code characterizing the magnitude of the monitored signal is compared with the codes characterizing the specified tolerances for the signal. The comparison results, which are the results of automatically conducted tolerance control of the sound signal level, are sent to block 13. In the latter, simultaneously with a digital indication of the signal size, which of the parameters is displayed and beyond which

0 tolerance out.

The device works in a similar way when monitoring the stereo channel B, while a tone signal, for example, 1000 Hz frequency using an external switch (not

5 is shown) is fed to the input of switch 14. To estimate significant phase shifts between stereo channels A and B at fixed frequencies, for example, at a frequency of 1000 Hz, the signal of the stereo channel B is fed to

0 the input of the switch 17, the output of which through the amplifier 12 and the switch 18, the signal is fed to the input of the adder 25.

Further processing of the signal from the output of the adder 25 is performed as described.

5 earlier way.

The control voltage for switching the switch 18 to the monostereo mode is generated automatically from the AB signal or from the complex stereo signal carrier, as well as manually by applying the corresponding constant voltage to the control input of the switch 18.

During stereo broadcasting, a dynamic signal (where the signal of the stereo channel B is fed to the input of switch 17) is controlled by low-frequency stereo signals by the summed A + B signal generated at the output of adder 25, the resulting signal of which is affected by both amplitude and phase changes in each from signals A and B. This signal through switch 16 is fed to filter 2 and further processing is carried out as previously described.

During stereo broadcasting, the monitoring of high-frequency paths, such as FM FM broadcasting transmitter, is performed as follows.

A high-frequency signal from the output of the transmitter is fed to the first input of the detector 24, from the output of which the complex stereo signal (CIL) through the switch 15 is fed to the input of the switch 16.

Control voltage to switch 16 can be supplied either automatically or manually. In this case, the signal from the adder 25 is turned off, and the complex stereo signal is input to the filter 2 input.

Before broadcasting, the device measures (by the method described earlier) the frequency deviation of the unmodulated subcarrier, and during broadcasting the deviation by the complex stereo signal.

From the second output of the detector 24, the voltage characterizing the power of the transmitter, through the switch 19, is fed to the input of the quadrant 22, from the output of which the signal is fed to the input of the switch 20.

Under the action of the control signal generated by the divider 26, the switch 20 alternately (at specified intervals) passes the low-frequency signal from the output of the integrator 4 to the input of the converter 5, then the transmitter power information from the output of the quadrant 22.

Consider the operation of the device when measuring power.

From the output of the converter 5, information is fed to the input of the memory block 23. From the output of block 23, the information arrives at the first input of the switch 21.

At the same time, information from block 5 is fed to the input of the 8-tolerance signal processing block. In block 8, the digital code characterizing the amount of power is compared with the codes characterizing the specified power tolerances. The comparison results, which are the results of an automatically conducted tolerance power control, are transmitted to the display unit 13.

Simultaneously from the output of block 8, the information about the output of power beyond the tolerance is fed to block 1, from the output of which the signal goes to the control input of the switch 21 and puts it into a state where the input of the block 13 receives information about the amount of power in this

moment of time. To indicate the amount of power at any time, it is necessary to manually send the appropriate external signal to the control input of unit 1.

When the transmitter power decreases below the limit characterizing the lack of power, information about this from the output of block 8 is fed to the first input of digital timer 9 and the countdown of the absence of power begins. Information about the time of no power is supplied to the switch 21. In this case, the output of block 1 generates a signal that puts switch 21 into such a state that information about the time of no power is received to the input of block 13 of the display, regardless of the value of all other monitored parameters. Thus, priority is given to the time indication of the absence of power.

When the low-frequency sound signal decreases below the limit, which is assumed to be a pause, information about this from the second and first outputs of block 7 is fed to the input of digital timer 9 and the second input of priority block 1, respectively, and the pause time begins. This information is fed to the input of the switch 21. At the same time, a signal is generated at the output of the block 1, which puts the switch 21 in such a state that the information about the pause duration in the low-frequency sound signal is input to the block of the display 13.

The clock generator 10 generates the clock pulses that arrive at the converter 5, blocks 7 and 8, digital timer 9 and divider 26.

Calibrator 27 generates a sinusoidal calibration signal, for example, with a frequency of 1000 Hz, which is fed through switches 14, 17 and 15 to the inputs of amplifiers 11 and 12 and switch 16, respectively, and is used to calibrate the corresponding paths. The calibration voltage from the first calibrator 27 is fed through the switch 19 to the input of the quadrant 22.

Switching switches 14, 17, 15 and 19 to calibration mode is carried out manually by applying external direct voltage to the control inputs.

The detector 24 of the audio signal (Fig. 2) works as follows.

When monitoring a television transmitter, the RF signal, which contains the image and sound carrier frequencies, is fed to the input of the attenuator 28, from which the signal goes to the input of the mixer 29. The intermediate frequency voltage allocated by the bandpass filter

30 and amplified by the intermediate frequency amplifier 31, is fed to the input of the frequency detector 33. The detected voltage through the switch 39, the amplifier, 43 low frequency and the switch 40 is fed to the first output of the detector 24.

The detection of additional information, such as the second audio of the television, is made by the frequency detector 34, from which the signal is fed through the low-frequency amplifier 45 to the third input of the switch 40.

To obtain information about the power of the television sound transmitter, an RF signal is fed through a switch 41 to the input of an amplitude detector 38, the detected voltage from which is fed through a filter 49 and an amplifier 51 to the second output of the detector 24.

When monitoring the FM transmitter's HF transmitter, the RF signal through attenuator 28 is fed to the input of divider 50. The division factor is chosen so that the signal frequency at the output of divider 50 is close to the intermediate frequency to which amplifier 32 is tuned. From the output of amplifier 32, the signal is fed to the frequency the detector 35, the detected voltage from which through the amplifier 42, the switch 39 and the amplifier 43 is fed to the first input of the switch 40.

Switching the switch 39 to VHF FM mode is carried out manually by applying an external constant voltage to the control input of the switch.

Additional information, such as a second broadcast program, is detected by a frequency detector 36, the output of which signals the signal through amplifier 44 to the second input of switch 40. To detect more broadcast programs, it is necessary to increase the number of serially connected frequency detectors 36 and amplifiers 44 connected to output of the frequency detector 35. The number of low-frequency signals arriving at the corresponding inputs of the switch 16 will also increase; in this case, switching It can be carried out manually or automatically according to a given program.

When monitoring the CB AM transmitter, the RF signal through the attenuator 28 is fed to the input of the amplitude detector 37, the detected voltage from which is fed through the filter 48 and the amplifier 46 to the fourth input of the switch 40.

The AGC block 47 allows the low-frequency signal level at the output of amplifier 46 to be automatically maintained within specified limits with significant changes in the transmitter carrier frequency level AM, for which also to the third input of amplifier 46

A voltage is applied from the output of the filter 49. To obtain information about the power of the VHF FM and MW AM transmitters, the RF signal from the output of the attenuator 28 is fed through the switch 41 to the input of the amplitude detector

0 38. Further signal processing is performed by the method described previously.

The parameters of the amplitude detector 38 and the filter 49 should provide information on the power (with the amplitude

5 modulation), corresponding to the silent mode (the modulation depth is zero).

Switching the switches 39-41 to the appropriate mode of operation is carried out manually by applying external DC voltage to the control inputs of the switch. The switching of the RF signals, performed by the switch 41, can also be performed, for example, by means of corresponding jumpers.

Claims (2)

1. A device for monitoring a sound channel, comprising a digital timer, a display unit, a first signal processing unit and a first amplifier, hence, an analog-code converter and a signal statistical processing unit, and a quasi-peak detector and integrator connected in series, characterized in that with the aim of 5 to increase the accuracy and enhance the functionality by increasing the range of measured parameters, the first switchboard is introduced, connected in series with the sound detector 0 signal, the second switch, the third switch and the low-pass filter, the output of which is connected to the input of the quasi-peak detector, a fourth switch connected in series, a second amplifier, 5th switch and adder, the output of which is connected to another input of the third switch, the calibrator, the sixth switch, the quad and the seventh switch, the output 0 which is connected to the first input of the analog-code converter, and the second input is connected to the integrator output, serially connected clock generator and frequency divider, the output of which 5 is connected to the third input of the seventh switch, the memory unit connected in series and the eighth switch, the output of which is connected to the first input of the display unit, are connected in series to the second tolerance signal processing unit and the priority block, the output of which is connected to the second input of the eighth switch, the output of the first switch through the first amplifier is connected to another input of the adder, the second output of the calibrator is connected to the second input of the second switch, to the first input of the fourth switch, and the second the input of the sixth switch is combined with the third input of the second switch, with the second inputs of the first and fourth switches and is the first control input of the device, the first information input of which It is the third input of the first switch, the second input is the third input of the fourth switch, the third and fourth inputs are, respectively, the first and second inputs of the audio detector, the second output of which is connected to the third input of the neck switch, the output of the analog-code converter connected to the input of the memory unit, to the first inputs of the first and second blocks of the pre-processing, the output of the clock generator is connected to the clock inputs of the analog-code converter, the first and second blocks of the starting processing signal and digital timer, the first output of the first signal processing unit is connected to the second input of the priority block and to the second input of the display unit, the third input of which is connected to the first output of the second signal processing unit, the second output of which is connected to the first input of the digital timer, second input which is connected to the second output of the first signal processing unit, and the output is connected to the second input of the eighth switch, the third input of which is connected to the output of the statistical processing block TKI signal. 2. The device according to claim 1. distinguishes with the fact that the detector of the audio signal with 0 5 0 5 0 5 0 five holds the first low-frequency amplifier, serially connected attenuator, mixer, band-pass filter, first intermediate frequency amplifier, first frequency detector, first switch, second low frequency amplifier and second switch, serially connected frequency divider, second intermediate frequency amplifier, third, fourth frequency detectors and the third low-frequency amplifier, the output of which is connected to the second input of the second switch, are connected in series to the second frequency detector, quarters a low-frequency amplifier whose output is connected to the third input of the second switch, a first amplitude detector, a first low-pass filter, a fifth low-frequency amplifier, and an automatic level control unit whose output is connected to the second input of the fifth low-frequency amplifier whose output is connected in series to the fourth input of the second switch, a third switch connected in series, a second amplitude detector, a second low-pass filter and a DC amplifier; combined with a third input of the "fifth low-frequency amplifier; The output of the third frequency detector U through the first low frequency amplifier is connected to the second input of the first switch, the first attenuator output is connected to the first input of the amplitude detector and to the input of the frequency divider, and the second output is connected to the first input of the third switch, the output of the first frequency detector is connected to the second frequency detector input, the first audio signal detector input is the attenuator input, the second input is the second input of the third switch, the first output is the second output of the switch, the second output of the output amplifier is a constant current. FIG. 2