SU1584126A1 - Analyzer of parameters of television transmitter - Google Patents

Abstract

The analyzer of parameters of a television transmitter is designed to measure and control its parameters and contains demodulator 1, three switches 2 ... 4, video switch 5, two synchro selectors 6 and 7, switch 8, control block 9, blocks 10 and 11 of processing luminance and chrominance signals , block 12 of dynamic memory, two blocks of ADCs 13 and 16, two blocks 14 and 17 of memory, two blocks 15 and 18 of signal parameter processing, block 19 of operational memory, block 20 of comparison, sensor 21 tolerances, block 22 of calculating statistical parameters , block 23 of the formation of data and display forms rovatel 24 slots, 25 code converter and the calibrator 26. The purpose of the invention, consisting in increasing the accuracy, while reducing the measurement time achieved by the use of optimal adaptive signal processing algorithms of image and sound. 2 Il.

Description

ate

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Fig 1

The invention relates to a television measuring technique and can be used to measure and control parameters of television transmitters.

The purpose of the invention is to improve accuracy while reducing the measurement time.

FIG. Figure 1 shows a structural electrical circuit for analyzing parameters of a television transmitter; in fig. 2 - time diagrams that show the operation of the analyzer.

The analyzer of the parameters of a television transmitter (Fig. 1) contains demodulator 1, first 2, second 3 and third 4 peak detectors, video switch 5, first 6 and second 7 sync selectors, switch 8, control block 9, block of signal processing 10, block 11 color signal processing unit, dynamic memory block 12, first analog-to-digital conversion unit 13 (A / D converter), first memory block 14, first signal parameter processing unit 15, second ADC block 16, second memory block 17, second parameter processing block 18 signals, block 19 RAM , comparator unit 20, tolerance sensor 21, statistical parameter calculation unit 22, data generation and indication unit 23, time generator 24, a code converter 25 and a calibrator 26.

The analyzer parameters of the television signal works as follows.

The radio signal is fed to the input of the radio signal from the tap of the transmitter's feeder, and to the inputs of sound signals and the full television signal - the corresponding signals from the inputs of the transmitter. The demodulator 1 generates three signals from the radio signal: the intermediate frequency signal (31.5 MHz according to GOST), the square of the amplitude of which is proportional to the radiated power of the radio sound signal, the sound signal, the quasi-peak span of which is proportional to the maximum deviation of the average radio frequency of the sound signal, and the full color TV signal, When applying to the control input of the demodulator 1 rectangular pulses

0

five

0

five

0

five

0

five

0

five

at its third output, together with the full color TV signal, pulses of zero carrier zero (zero level according to GOST) are extracted. The square of the difference in the level of the synchronizing pulses and the zero level is proportional to the radiated peak power of the radio signal of the image.

From the first output of the demodulator 1, the signal arrives at the first peak detector 2, the output of which produces a constant voltage proportional to the amplitude of the audio signal of the audio signal. At the outputs of the second 3 and third 4 peak detectors, signals are allocated whose span is proportional to the quasi-peak span of the sound signals, respectively, at the output and the input of the television transmitter. The quasi-peak range of the signal at the output of the second peak detector 3 is proportional to the maximum deviation of the average frequency of the transmitter’s audio signal.

Video signals from the input of the analyzer's TV signal and from the third output of demodulator 1 are fed in parallel to the second and first inputs of the video switch 5 and to the inputs of the first 6 and second 7 sync selectors, the outputs of which allocate the appropriate sync signals. With their help, the operation of the analyzer blocks is synchronized.

When measuring the parameters of the input television signal, the switch 8 connects the first sync selector 6 to the second input of the control unit 9, and when measuring the parameters of the image radio signal, the block 9 receives a signal from the output of the second sync selector 7. Switching the synchronization signals eliminates the effect of the signal delay in the image channel of the transmitter on the results of the analysis of its parameters.

The full color TV signal from the analyzer input or from the third output of demodulator 1 is fed to video switch 5 and then in parallel to the inputs of blocks 10 and 11 of the luminance and chrominance signals, respectively, at the outputs of which luminance signals and chrominance envelopes are output. unit 12, which ensures the memorization of the signal level at a characteristic point of the measured signal.

51

This device is fed to the input of the first ADC unit 13, to the second input of which a constant voltage is applied from the output of the first peak detector 2, proportional to the sweep of the audio signal. In block 13, the ADC signal level at the measurement point is converted to a digital code and stored in the first memory block 14.

In the first block of memory 14, the digital values of several signal levels necessary for calculating one or another measured parameter are stored (the algorithms for calculating the parameters are determined by GOST). Calculations of the parameters of the measured signals and the radio signal strength of the audio signal are carried out in the first block .15 of the processing of signal parameters, which also provides statistical processing of the measurement results of the corresponding parameters in order to increase accuracy and reduce the measurement time.

The parameters of the sound signals coming from the peak outputs of the second 3 and third 4 detectors are measured similarly. The discrete samples of the detected audio signals are converted into digital codes in the second ADC block 16, and then stored in the second memory block 17. The calculation of the parameters of these signals is carried out by block 18.

The measurement results of the parameters generated by the blocks 15 and 18 are stored in the memory block 19. Digital codes from block 19 are received in parallel to a comparison block 20, in which they are compared with tolerance sensor codes 21, to block 22

statistical parameters, in which statistical parameters of a television transmitter are calculated by successively received measurement results, and at the input of unit 23 for outputting them to an indicator and for generating a data table. The signals from the output of the comparator unit 20 are supplied to the input of the generator of 24 time intervals, at the output of which a code is formed that is proportional to the time that the value of one or another parameter leaves the set tolerances. This code, as well as the data from the output of block 22, are stored in the operational memory block, the incoming

6

into block 23. Measurement results, ordered by the dacha table generator in block 23, are fed to the telemetry channel for remote indication and to the code converter 25, the output of which forms a display signal on the display.

The operation of all the analyzer units is carried out via the control bus of the control unit 9, while the bus carries out both the programming of the individual units and their switching, which allow the structure of the analyzer of the television transmitter to be changed during operation. For example, at the command of the block °, instead of the main input signals, the inputs of the respective blocks can be supplied with the outputs of the calibrator 26, which allows for the prompt correction of measurement errors.

Block 9 can be implemented both in hardware and in the form of a microprocessor device.

The analyzer of parameters of a television transmitter can operate either in the mode of measuring one of the specified parameters, or in the cyclic mode of measuring the sequence of several parameters. The measurement mode is selected by block 9, which is controlled by operational control digital inputs, from which the operating mode of the analyzer is set. The control signals of the analyzer units are generated in the control unit 9, which receives a TV sync signal from one of the sync selectors 6 or 7 through the commutator 8.

The measurement process is divided into two stages. At the first stage, the signal parameters are measured, and at the second stage, the parameters of the calibrator 26 are measured. Next, the measurement of the measurement result is corrected to increase the measurement accuracy. Let him make a measurement of the relative value of the unmodulated residue by the carrier. This value is determined by

H (1 - -100 O)

de UH is the amplitude of the image carrier signal when transmitting the sync pulse level;

Swipe a complete TV signal in the picture radio signal.

When measuring this value, the signal from the third output of demodulator 1 is used (Fig. 2a, b). The magnitude of the total TV signal (Ure) is determined by the difference in the level at which. point b is located ((middle of white pulse level B2 in test line, fig. 2a) and sync level (point S). To determine the carrier amplitude in the radio signal of the image to the control input of demodulator 1 (fig. 1) from the unit 9, a rectangular impulse is placed, for example, in the fifth line of the TV signal. This impulse beats the zero carrier and a pulse arises in the output TV signal (in Fig. 2a, a dashed line) 9 whose vertex level (dot ) corresponds to the zero-carrier level in Dio signal In this case, the signal swing between the level of point b2 and the level of clock pulses (point S) corresponds to the value UH.

In the 4H measurement mode, initially the video switch 5 (FIG. 1) connects the third output of the TV demodulator 1 to the inputs of blocks 10 and 11. The block 10 of the luminance signal processing unit provides filtering of the full TV signal (elimination of the color subcarrier) Low-Frequency Filtering and Fixing a Constant Level of a TV Signal In this case, the fixation pulses correspond to the transfer of a level of clock pulses (fixing a constant level of a TV signal allows rational use of the dynamic range of the 13th ADC unit).

The bandpass filter located in the color signal processing unit 11 provides for the selection of color subcarriers (Fig. 2c) from the full color TV signal. Further, the envelope of the color signal is separated from the signal (FIG. 2d), and then the signal level is recorded outside the limits of the transmission of the color signal.

From the outputs of blocks 10 and 11 signals; arrive at the inputs of the block 12, in which the signals of the control block 9 fix the instantaneous values of the input signals of the block 12,

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. d

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five

on which then the relevant parameters are measured.

After the end of the measurement of the signal level at point C (in the first frame of the TV signal), the signal level at point S is measured in the same way (sync level, Fig. 2a). The measurement result is also stored in block 14 (Fig. 1) of the memory. The results of these two measurements in block 15 are used to calculate the difference between these levels U | 6, which may differ from the value U (Fig. 2a) due to errors in signal processing in blocks 10-13 (Fig. 1).

A calibrator 26 is used to increase the accuracy of the conversion. It provides a signal formation (Fig. 2e) containing elements similar to the measured elements of a full color TV signal (reference sweep, white pulse, zero beat reference pulse, 3.9 sinusoidal frequency oscillations). , 4.43, 4.76 MHz)

After measuring U g & video switch 5 switches to the inputs of blocks 10 and 11 a signal (Fig. 2d) from one of the outputs of the calibrator 26. In this case, the span of the Calibrated TV signal (Fig. 2d) between the points b (and S) is measured in the same way. U TBo is also fixed at block 15, and then the true value of U T6 is calculated using the formula

UTB °

ITY & ™ AND; IN-

those about where UTO is the true value of caliber °°,

digital signal

which is in block 15.

Similarly, the value

U. (Fig. 2a) and calculated Lm by fori / l n °

mule (1). ;

To increase the accuracy of the parameter measurements and eliminate the misses, but But is measured many times. Thus, n values of the measured

parameter 4H ((P: Lm, 4 and, ("|,, DNp (PG These values in block 15 of the calculation and statistical processing of the parameter are set in order of magnitude, i.e. turn into a random statistic, and then from this the sequences exclude the smallest (t) and the highest "(n) values (potential measurement misses).

From the obtained sequence Ln, c (d), (and. (), The average is calculated by the formula

H - -i-2

V4cMf 2

which is the result of the measurement.

The measurement results are recorded in the RAM of the unit 23 and can be further displayed directly or arrive at the output of the analyzer.

In addition, in block 15, the values of the measured parameter u and / g and JH are memorized (storing these values reduces the measurement time of this parameter in the next measurement cycle, which initially takes the T-dimension of the parameter A h, and m p. Similarly, other transmitter parameters are measured.

Thus, the relative change in the range of color synchronization in the rows D g is carried out according to the formula

U (U

"eight,

U

Ooh

Uwick

Y "their

Ur

- 1) - 100%, (3)

6x

vex11 Uv6tu, where U0 and U0 - respectively

the color sync signal flips in the lines Df (frequency 4, 76 MHz) in the input TV signal and in the TV signal at the output of demodulator 1 (Fig. 1), respectively; respectively, the white pulse B2 sweeps in the input TV signal and in the TV signal at the third output of demodulator 1.

In accordance with algorithm (2), the process of measuring this quantity is divided into several stages. At the first stage, the video switch 5 provides, on command from the output of block 9, to feed the blocks 10 and 11 of the input TV signal and measure its levels at points bt and C (through block 10, in Fig. 2, the signal at the output of this block is not shown) it is similar

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five

0

five

0

five

0

five

0

five

The signals of FIG. 2a, b, but without filtered color subcarriers) Then, the signal levels at the output of block 11 (Fig. 2d) are measured at points bj and b4, the difference in levels at these points is proportional to the color burst. After that, the video switch 5 connects the third output of demodulator 1 to the inputs of blocks 10 and 11, and similar measurements are made in the TV signal at the output of demodulator 1. Video switch 5 connects the outputs of calibrator 26 to the inputs of blocks 10 and 11, and the corresponding The levels in the signals of FIG. 2d and e (at the output of block 11).

Using digital standards of the values of UVe (Fig. 2d) and U Ј o (Fig. 2e), in block 15, the conversion results are corrected and the value of ЈR is calculated by the formula (2). Further, the process of statistical processing of this parameter is carried out similarly to the process of statistical processing of the parameter

L but

The measurement time of each parameter is in the order of 0.5-2 seconds, so that the total cycle time for measuring ten parameters is about 10 seconds. Because of this, in the measurement cycle of parameters it is also impossible to include measurements of the quasi-peak range of the input dynamic sound signals and the maximum deviation of the average radio frequency of the sound signal. In connection with this, the analyzer uses a separate channel for measuring these parameters.

The audio input signal and the signal from the first output of demodulator 1, the quasi-peak span of which is proportional to the maximum deviation of the average frequency of the radio audio signal, through the same peak detectors 3 and 4 are fed to the two inputs of the second ADC block 16, to the first input of which the signal from the second output of the calibrator 26, containing a sinusoidal signal generator of an audio frequency of a reference swing (for example, 1 kHz) and a peak detector, similar to the peak detectors 3 and 4.

The parameters of peak detectors 3 and 4 correspond to the requirements imposed on the processing circuits of such signals in standard gauges (according to

One hundred charge time 5-10 ms "discharge - 3-4 s). As a result, to ensure high accuracy of the measurement, the frequency of the audio signal levels should be no more than 1 ms (during this time, the peak detectors

3 and 4 is not more than 0.3%).

The measurement of the level of the reference signal from the output of the calibrator 26 can be made much less frequently (determined by the stability of the parameters of the g | ikovyh detectors).

Block 16-ADC is similar in construction to the first block 13 of the ADC and is distinguished by the presence of three measurement channels, which are switched by signals from the output of control block 9. Thus, the ADC block 16 provides alternate conversion of signal levels with output of peak detectors 3 and

4- In addition, a measurement of the reference signal from the output of the calibrator 26 is performed once every few seconds. The results of these measurements are stored in the second memory block 17 and fed to block 18. Blocks 15 and 18 can be combined. In this case, the process of their control is somewhat complicated: the processing of the sound accompaniment signals must be interleaved with the processing of the parameters of the TV signals.

Block 18, in addition to correcting the results of analog-digital conversion of sound signals using a digital standard of the effective voltage of a sinusoidal audio signal generated by calibrator 26, calculates the maximum value of sound signal levels over a certain time interval determined by the technical operation rules of television transmitters, calculates the duration of the pauses of the sound of the television, etc. The results of the current measurements generated in block 18 are also stored in block 19. Changing measurement cycles is carried out by applying a signal from the second output of block 18 to the second input of block 9 of the control.

After recording the measurement result of a parameter, a digital code enters the comparison unit 20, the statistical parameter calculation unit 22 and the data generation and display unit 23. To another input of block 20

0

0

g

five

0

at the same time, the tolerance code of the measured parameter is supplied from the tolerance sensor 21, made in the form of a standard ROM, to the address inputs of which signals are received from the control unit 9. Comparison unit 20 comprises a set of comparison circuits and memory circuits, on the outputs of which a signal is generated if the measurement result exceeds the specified tolerance limits. This signal is fed to the input of the imaging unit 24 time intervals, representing, for example, a set of external-start generators and counters, the outputs of which generate a code corresponding to the time the measured parameter is outside the set tolerances. This code is stored in RAM of the maker 23. Block 22, executed, for example, in the form of a microprocessor calculator, provides for the calculation of the transmitter’s statistical parameters from the results of the measurements filled in the RAM block 19. Block 22 contains a measurement cycle counter N. The calculation of statistical parameters is carried out using recurrent formulas.

The average value of each parameter on the N-M measurement cycle is calculated by the formula

t,

 (one

54i

(four)

Where

0

t

N-1

measurement result of the parameter on the Nth measurement cycle;

the average value of the parameter on the (N-1) -M measurement cycle.

Taking into account that the calculation of each parameter is carried out from a measured set of several signal levels and that the error in measuring levels is mainly due to the presence of fluctuating interference in signals, it is possible to consider with great certainty the distribution of measurement results as normal. Therefore, the entropy deviation of each of the measured parameters, which characterizes the instability of television transmitter operation during its operation, can be calculated from the recurrent formula

EO

N 2,076m

(five)

Where

6-4-4C, -.- V-V

Thus, unit 22 provides the calculation of average values of parameters of a television transmitter, characterizing the quality of its settings, and entropy deviations of parameters that determine the instability of its operation. The results of these calculations are also stored in RAM RAM 23.

Measurement and calculation results are displayed on digital and light indicators of shaper 23 and are fed to shaper of shaper data table 23, which contains RAM, in which, in a certain sequence, commands from control block 9 record data from OZK and ROM, in which codes are written, determined Names of the measured parameters, designations of the type of the generated data (current protocol, statistical data protocol, indication of the output intervals of the measured data beyond the established tolerances, etc.). The read sequence of the codes recorded in the imaging unit 20 is determined by signals from the control unit 9.

This data enters the channel body

metrics (e.g., in a teletype code) for remote registration and are fed to the input of the converter 25 of the code to which control signals are received from control unit 9, as well as signals from the output of the first sync selector 6.

The code converter 25 is executed as a serially connected input register that converts a serial data code into a parallel, RAM, in which data is written during the reverse sweep and read during the forward sweep of the television display, a mask ROM that converts the recorded in RAM codes into character codes of the alphabet, arithmetic signs and numbers, an output register that converts a parallel code from the output of a mask ROM to a serial code, and an addendum in which the generated code edovatelny code summed with the clock signal coming from

five

JO

15 0 5 0

five

P

five .

five

output of the first sync selector 6. The output signal of the code converter 25 provides the display of the results of the analyzer operation on the television display screen.

The measurement accuracy of the parameters of a television transmitter using the proposed analyzer is about 1% and higher than the measurement accuracy of a known analyzer at least 2 times. Statistical studies of transmitting television stations show that this results in a reduction in measurement time by a factor of 2-3.

Claims (1)

Invention Formula The analyzer of the parameters of a television transmitter containing a demodulator, whose input is an input of a radio signal, and the first and second outputs are connected to the inputs of the first and second peak detectors, respectively, the third peak detector, the input of which is an audio signal input, the first analog signal block. digital conversion (A / D converter), the first memory block, the video switch, the first input of which is connected to the third output of the demodulator, and the second input is the input of the television signal, the first clock switch, a switch, a serially connected tolerance sensor and a comparison unit, a data generation and indication unit, as well as a control unit, the control outputs of which are connected to the control inputs of the switch, video switch, the comparison unit, the tolerance sensor, the first ADC unit and the first memory block that, in order to increase accuracy while reducing the measurement time, a calibrator, a dynamic memory block, a second ADC block, a second memory block, the first and second signal parameters processing blocks were introduced, RAM, driver, time intervals, statistical parameters calculation unit, code converter, as well as the second sync selector, with the inputs of the first and second sync selectors connected respectively to the second input of the video switch and the third output of the demodulator, and the outputs of the first and second sync selectors are connected (Responsible with the first and second inputs of the switch, the first input of the control unit is the input of the Operational control signals, the second input is connected to the output of the switch, control outputs are connected to control inputs of the calibrator, luminance signal processing units and signal chrominance, dynamic memory block, second ADC block, second memory block, first and second signal parameters processing unit, main memory unit, time generator Valuable intervals, Statistical parameters calculation unit, data generation and indication unit and code converter, first whose input is connected to the output of the first synchro- 4ector, the second input is connected to the output of the data generation and indication unit and is the output of the telemetry signal, and the output is the output of the result display signal HA, a first output calibrator connected to the third input switcher whose output is connected to the input Ii processing blocks and chrominance signal processing rkostit outputs of which are respectively connected to first and second inputs of dynamic memory unit, the output of which through the first ADC unit connected to the input Q 0 five The first memory block and the second input of the first ADC block are connected to the output of the first peak detector, the first, second and third inputs of the second ADC block are connected respectively to the second calibrator output and to the outputs of the second and third peak detector, and the output is connected to the input of the second memory block These outputs of the first and second memory blocks are connected to the inputs of the first and second parameter processing units, respectively, the first outputs of which are connected to the first and second inputs of the random access memory, respectively, and the second outputs Connected respectively to the third and (fourth inputs of the control unit, the first output of which is connected to the first input of the data generation and indication unit, the second and third inputs of which are connected to the outputs of the statistical parameters calculator and time interval generator, respectively, the first and second inputs the second output of the control unit and with the output of the comparison unit, and the output of the main memory unit is connected to the second input of the comparison unit, with the input of the statistical calculation unit parameters and with the fourth input of the data forming and display unit. J I-1 "H : uh