SU535521A1 - Device for measuring the characteristics of group latency in communication channels - Google Patents

Description

Receiver 2 consists of signal extraction units 12 and 13. The output of the signal extraction unit 12 is through the bipolar phase converter 14 and the averaging block 15 is connected to one input of two recording elements OR 16 and 17. The output of the block 13 through the frequency divider 18 by two, the second bipolar phase converter 19 and the second averaging block 20 with other inputs of the elements OR 16 and 17. The outputs of the latter are connected to block 21 of the subtraction and registration. Elements OR 22 and 23 are connected to the outputs of each of the phase converters 14 and 19, and the outputs of the latter are connected to the subtraction inputs of blocks 15 and 20. Synchronization unit 24 is connected to all the mentioned blocks and receiver elements, except the blocks 12, 13 for extracting signals. containing a quartz oscillator 25 pulses, a phasing unit 26, a summing element OR 27, a distributor 28, a control unit 29 permitting and triggering elements OR 30 and 31. Averaging blocks 15 and 20 contain locking elements AND 32 and 33, averaging dividers 34 n 35 and switches 36 characters summation, and the averaging dividers of the averaging block 15 have a factor of de „6 laziness, equal to n, and in the average averaging

20 - division factor equal to 6 liters.

The device is based on the algorithm defined by the ratio

„- 2

J

where TI and T2 are the time shifts of the envelopes with the frequencies QI and J2, respectively, at the output of the channel under study;

Qr ,

  In the device, to simplify its implementation, the ratio P is chosen equal to 2, i.e., the device has a measurement algorithm 41

eleven

2 The device operates as follows.

From the output of the transmitter 1 to the input of the channel 3 under study, the signals of the reference and measuring signals are received alternately. The envelope of each burst is an oscillation consisting of two frequencies with a ratio equal to two. To obtain such a vibration, one of the inputs of the modulator 4 receives a modulating voltage from source 5, formed by adding oscillations at the output of generators 9 and 10 in the adder 11. The second input of the modulator 4 is alternately fed by a carrier oscillation of the reference and measuring frequencies from source 6 through a frequency switching unit 7 automatically controlled by the control unit 8.

Received at the output of the channel 3, the signal is fed to the inputs of two blocks

12 and 13 of the signal extraction and control unit 29, in which the signals for the presence of a reference or measurement signal are generated, the signal "Reset 1, coinciding in time with the beginning of the reference message, and" Reset 2, coinciding in time with the beginning of the sending of the measurement or reference signal. These signals are necessary to obtain the appropriate algorithm for processing the phase envelopes of the test signals. When the receiving signal arrives at the input of the receiving device, all elements of the discrete device node circuit are reset with the signal Reset 1.

From the output of the test channel 3, the test signal is fed to blocks 12 and 13, where the envelope voltage is divided in frequency and converted into square-shaped pulses with frequencies And and 2Q. From the output of block 12, rectangular pulses with a frequency of Q follow simultaneously to the measuring input of the bipolar converter 14 phase and to one of the inputs of the summing element OR 27. The rectangular pulses with a follow frequency 2Q from the output of block 13 through the divider 18 frequency two come simultaneously to the measuring input of its bipolar converter 19

phase and to the second input of the summation, its element OR 27.

On the output of the latter, pulses appear, the duration of which depends on the phase difference of the signals at the outputs of the unit 12 and the frequency divider 18 by two, which are fed to the input of the distributor 28.

After a time equal to Go / p (where T0 is the pulse period with a frequency Q, and m is an integer), the first output of the distributor 28 shows the signal Measurement resolution, which opens the matching elements AND 32, 33 of the corresponding blocks 15 and 20 averaging, and starts the phasing unit 26, as a result, rectangular pulses appear at the output of the latter, the phase of which approximately coincides with the phase of the reference signal at the outputs of the allocation unit 12 and the frequency divider 18 by two. These pulses go to the reference inputs.

bipolar transducers 14 and 19 of the phase and to the third input of the summing element OR 27. The duration of the pulses at the output of the latter depends on the phase shift between the pulses at the outputs of the allocation unit 12

signal, a frequency divider 18 into two, and a phasing unit 26, and is equal to the time intercalation between the leading edge of the leading edge and the falling edge of the lagging pulses. The falling edge of these pulses corresponds to

Claims (2)

end of one measurement. The difference in pulse durations on the summing and subtracting outputs of each of the bipolar transducers 14 and 19 of the phase is equal to twice the time between the signals at the inputs of these transducers. The calculation of the number of measurements is carried out with the help of the distributor 28. After the measurements at the second output of the distributor 28, the signal "The end of measurements appears, which closes the locking elements AND 32, 33 of the respective averaging blocks 15 and 20. Thus, at the outputs of the bipolar converter 14 of the phase, two series of pulses appear, the total difference of the durations of which is x - z 2 2 A., where AT / is the time shift between the signals at the inputs of the bipolar converter 14, when entering input receiver send the reference signal. At the outputs of the bipolar converter 19, two series of pulses also appear, the total difference of the durations of which is m 2 2, where m / is the time shift between the signals on the inputs of the bipolar converter 19 when the input to the receiver of the reference signal is received. The pulses from the bipolar transducers 14 and 19 are fed to the corresponding elements OR 22 and 23 and blocks 15, 20 of averaging. As a result, a logical subtraction of the pulse durations coming from the outputs of the bipolar transducers 14 and 19 of the phase, and filling the difference pulses with high-frequency pulses coming from the output of the quartz oscillator 25 occurs on the locking elements AND 32 and 33 of the corresponding averaging blocks 15 and 20 and the resulting pulse packets arrive further on the corresponding dividers 34 and 35, and the division factor of these dividers in the averaging block is equal to - / g, and in the averaging block 20 - 6 l. The pulses from dividers 34 and 35 through their switches 36, the summation symbol and the recording elements OR 16 and 17 are received in block 21, where they are written to the corresponding phase-memorizing dividers so that the difference in the numbers recorded in them is equal to. where fi- is the frequency of the high-frequency pulses of the quartz oscillator 25. When the receiving device arrives at the sending device of the measuring signal in block 29, the signals "Measuring parcel and" Reset 2. The “Reset 2” signal all circuit elements, except blocks 26 and 21, resets to the initial state. The sigpal phase at the output of the phasing unit 26 remains the same as when the reference signal is sent. The process of comparing the phases of the signals at the output of blocks 12 and 13 is similar to the case when the input of the device for sending the reference signal, while the signals from blocks 15 and 20 are recorded in opposite memory dividers of block 21 compared to the case of the input frequency signal at the input of the receiving device 1. As a result, the usefulness of the numbers underestimated into phase-memory dividers is 4 /. 1 (IX (2 A- / - 2 D where m is the time shift between the signals at the inputs of the bipolar converter 14 when the receiving device sends a measuring signal to the input; L, is the time shift between the signals at the inputs of the bipolar converter 19, when entering At the input of the receiving device of the measuring parcel. At the simultaneous occurrence of the signals "End of Measurement and Measuring Package, the output of the AND 30 element is a trigger enable signal for phase memorized HEX dividers of block 21, which opens the trigger element AND 31. As a result, high-frequency pulses through element 31 and recording elements P1LI 16 and 17 simultaneously arrive at the inputs of the phase-memorizing dividers of block 21. And the output of these divisors appears rectangular pulses shifted in time by the value of the measured value of the group latency time 8 equal to - measuring, measuring and recording the time shift of these pulses is carried out in block 21. Claim of the invention A device for measuring characteristics of a group delay time in communication channels, comprising IR alternating parcels of the reference and measurement signals and a receiver consisting of a signal extraction unit connected by its output to a cryptographic unit and through a bipolar phase converter with an OR element connected to its outputs and an averaging unit which outputs through two recording elements OR connected to the subtraction and recording unit, characterized in that, in order to reduce instrumental and methodological measurement errors, it is provided with series-connected second signal extraction unit, frequency converter for two, a second bipolar phase converter with a second OR element connected to its outputs, and a second averaging unit connected between the input 7 receiver AND additional inputs of the recording elements OR, and the control inputs of the second averaging unit are connected to the inputs of the first averaging unit, the reset output of the synchronization unit is connected to the frequency divider input of the same name, and the second averaging unit, the output of the frequency divider is connected to the summing input of the synchronization unit, and the second input of the second bipolar phase converter is connected to the second input of the first phase converter.