SU1163279A1 - Device for determining standard deviation of phase fluctuation - Google Patents

Abstract

A DEVICE FOR DETERMINING A MEDIUM-SQUADRATIC FLOATTATION OF A PHASE containing an amplifier limiting device, three elements of coincidence, a generator, a trigger, a counter and an indicator the amplifier limiter i the second input of the second element is connected to the output of the generator, and its output through the counter to the output of a zero trigger setting, characterized in that, in order to increase t It is additionally equipped with second and third counters, a delay unit and a second trigger, the input of a single installation of the second trigger connected to the starting input of the device, and the output to the first input of the third coincidence element whose output is connected to the input of the second counter, an intermediate the output of the second counter through the delay unit is connected to the input of the single installation of the first trigger, and the output with the input of the zero installation of the second trigger, the third input of the first coincidence element is connected to the generator output and the output is connected to the input of the third counter, the outputs of which are connected to the inputs of the indicator, while the second input of the matching element is connected to the output of the amplifier-limiter.

Description

The invention relates to a measurement technique and can be used in phase radio engineering. The purpose of the invention is to improve the accuracy by introducing additional elements and connections into the devices, which provide the formation of signals, the duration of which is determined by the value of the phase fluctuation and significantly exceeds the duration of the signals in the known devices. When measuring the generated signals, instrumental errors will lead to minor errors in determining the rms deviation. fluctuations in phase. Fig. 1 shows a block diagram of a device for determining the standard deviation of phase fluctuation; FIG. 2 is a diagram of a delay unit. The device contains a trigger 1, the output of which is connected to the first input of the coincidence element 2, the second input of which is connected to the output of the limiting amplifier 3, and the output to the input of the counter 4. The output of the counter 4 is connected to the input of the zero setting of the trigger 1, and the intermediate output of the counter 4 through the delay unit 5 to the input of a single installation of the trigger 6. The output of the trigger 6 is connected to the first inputs of the elements 7 and 8 of the match. The second input of the coincidence element 8 is connected to the output of the amplifier-limiter 3, and its third input is combined with the second input of the element 7, hours: falling and connected to the output of the generator 9. The output of the coincidence element 7 is connected through the counter 10 to the zero-setting input of the trigger 6, The output of the coincidence element 8 is connected to the input of the counter 11, the outputs of which are connected to the inputs of the indicator 12. The counter 4 consists of two counters and a pulse former. The pulse generator input is connected to the output of the first counter, and its output is connected to the input of the second counter, the output of which is the output. counter 4. The intermediate output of counter 4 is the output of the pulse body. The delay unit 5 (Fig. 2) consists of the trigger 13v of the coincidence circuit 14, the high-frequency generator 15 and the counter 16. The counter 11 consists of successively connected decimeters. Indicator 12 consists of decoders i, the number of which is equal to the number of decimal counters included in counter I1 and the same number of indication lamps. The outputs of each decoder are connected to the outputs of the corresponding decimal counter, and the outputs are connected to the indicator inputs. The device works as follows. The measured signal is fed to the input of the amplifier-limiter 3 and from its output to the input of elements 2 and 8 of coincidence. Before the start of the measurement, the triggers 1 and 6 are in the zero state, the low potentials from them arrive at elements 2 and 8, and the signals at the output of the elements do not pass. The counters 4, 10, and 11 are reset. The measurement starts when the starting pulse arrives at the input of the single-set trigger 1. The high potential from the trigger I goes to the element 2 coincident, and the measured signal from its output goes to the input of the counter 4. From the intermediate output of the Counter 4 to the input of the unit 5 delays arrive pulses that coincide with the trailing edges of the measured signal. The pulse repetition period is close to the correlation interval of phase fluctuations f. Upon arrival at the input of the delay unit 5 (the input of a single installation of the trigger 13) pulse, the trigger 13 goes into one state and a high potential from its output goes to the coincidence circuit 14. High-frequency pulses from the generator 15 begin to arrive at the input of the counter 16. When the counter 16 overflows, the pulse from its output is delayed relative to the input by an interval and a multiple of the frequency of the received signal, sent to the input of the zero-set trigger 13 and to the output of the block 5. The trigger 16 is set to a zero state and a low potential from its output prohibits the passage of high frequency pulses through a circuit 14 of coincidence. The magnitude of the gap is determined by the period of high-frequency pulses and the capacity of the counter 16. From the output of the delay unit 5, the pulses arrive at the input of a single installation of trigger 6. High potential from trigger 6 goes to elements 7 and 8 of coincidence. The high-frequency pulses from the oscillator 9 are fed through the coincidence element 7 to the counter 10. The capacity of the counter 10 is chosen as. where the pulse at its output appears at a time interval equal to half the period of the frequency of the measured signal and places the trigger 6 in the zero state. At the trigger output, reference signals are formed, the duration of which is equal to half the period of the frequency of the measured signal. The reference signals from trigger 6 arrive at the first input of element 8, the second input receives the measured signal from the limiter amplifier 3, and the third input receives high-frequency pulses from the oscillator 9. When the phase of the applied signal fluctuates, the reference signals partially coincide with positive half-periods measured my signal. The duration of the coincidence intervals is determined by the difference between the intervals containing a fixed number of periods of the received signal (the duration of these intervals also exceeds fi.) And the intervals whose duration is ziaA of the nominal duration of the same number of periods. Packs of pulses from the output of element 8 coincidence corresponding to the intervals of coincidence are fed to counter I and summed there. The measurement time (the number of summed packs of impulses) is given by the capacity of counter 4. When counter 4 overflows, the pulse from its output goes to the zero-set trigger input G Low potential from trigger I, it arrives at element 2 of coincidence and prohibits the passage of a signal to its output. The measurement of the phase fluctuations then ends. The number recorded in counter II is indicated by the indicator 12. It determines the average duration of the coincidence intervals, and the last - the standard deviation of the phase fluctuation. The proposed device for determining the standard deviation of the phase fluctuation, in contrast to the known, allows an increase in the measurement accuracy. Indeed, to determine the root-mean-square deviation of the phase fluctuations, the deviations of the half-period duration of the received signal from the nominal half-period duration are measured in the known device. However, if the phase of the received signal fluctuates slowly, for example, the received signal is a narrow-band mixture of a sinusoidal signal with noise, then the duration of the half-periods of the received signal will almost coincide with the nominal duration. The duration of the half-period of such a signal has a normal distribution law with a mathematical expectation equal to the nominal duration of the signal's period. The magnitude of the standard deviation (fluctuations of the half-period duration is determined by the following expression: 7fef№-) where "is the signal-to-noise ratio of the received mixture; the nominal frequency of the received signal; the normalized value of the correlation function of narrow-band noise at an interval equal to the nominal half-period duration. The calculation of R (t) is made according to the following formula:), where f is the width of the spectrum of the received signal of the mixture. The magnitude of the fluctuations of the phase ai for the signal-to-noise mixture is calculated on the basis of barely. the following formula: Let 10 kHz and d 10 Hz. When we have (glad. 675 "0.005 ISS, and when" "2, 5 happy, i, 0.0075 µs. In the known device for determining the magnitude, small intervals are determined (their lengths are determined by the deviations of the received signal optical patterns. The actual duration of the popup iodine is;), whose duration is close. Instrumental errors in measuring such small intervals lead to considerable errors in determining 6i /. In the proposed device, the measured intervals are determined by the difference

two intervals. The first interval is equal to the total duration of a fixed number of periods of the input signal and exceeds the duration of the correlation interval T of the received phase.

signal (g d) second interval

equal to the nominal duration of the same number of signal periods.

RMS times i 2

these intervals & rv

times the value of the fluctuation by the front of the received signal (since it is determined by the difference of the positions of two independently fluctuating fronts). With values of 3 and 2. The corresponding values of br are approximately II and 16 µs. When measuring intervals close to 4p, instrumental errors lead to a negligible error in determining dr.

entrance

1 beep / a

entrance

sixteen

J

Phie.1

2

Claims (1)

DEVICE FOR DETERMINING RMS deviation of phase fluctuation, comprising an amplifier limiter, three coincidence elements, a generator, a trigger / counter and an indicator, the first inputs of the first and second coincidence elements being combined and connected to the trigger output, the second input of the third element coinciding with the output amplifier-limiter, the second input of the second element is connected to the output of the generator, and its output through the counter - with the output *. zero installation trigger "characterized in that, in order to increase accuracy and ,,. it is further provided with second and third counters, the delay unit and the second trigger, wherein,. the unit input of the second trigger is connected to the start input of the device, and the output is connected to the first input of the third matching element, the output of which is connected to the input of the second counter, the intermediate output of the second counter through the delay unit is connected to the unit input of the first trigger, and the output is with the input zero setting of the second 5 flip-flops, the third input of the first coincidence element is connected to the generator output, and the output is connected to the input of the third counter, the outputs of which are connected to the indicator inputs, while the second input is the first .sovpadeniya th element coupled to an output limiter amplifier.