SU1185262A2 - Apparatus for measuring characteristics of random process crossings - Google Patents

Abstract

DEVICE FOR MEASUREMENT OF CHARACTERISTICS OF CROSSOVERING OF RANDOM PROCESSES by auth. No. 658494, characterized in that, in order to increase accuracy, an adaptive threshold voltage shaper was introduced into it, the input of which is connected to the auxiliary output of the function shaper, and the output is connected to the second input of the pulse shaper.

Description

The invention relates to radio measurements. The purpose of the invention is to improve accuracy by reducing the spread of the values of the measured characteristics of the intersections of random processes at threshold levels other than zero. FIG. 1 is a functional diagram of a device for measuring the characteristics of random process intersections; in fig. 2 is an example implementation of an adaptive threshold voltage generator. The device contains serially connected function 1 shaper, driver shunt and inverter 3, interval-code converter 4, address counter 5, N-inflow decoder 6, logical elements AND 7 and pulse counters 8 as well as a gate generator 9, the output of which is through switch 10 connected to the input of the delay element 1 1 and the input of the differentiating circuit 12 and directly to the first Either trigger with separate start 13, the second input of which is connected to the output of the pulse former 2 and one of the switch inputs Yucchel 10, the remaining inputs of which are connected to the trigger output with separate start 13, while the output of the delay element 11 is connected to the second input of the address counter 5, and the output of the differential circuit 12 is connected to the second inputs of logic elements And 7, as well as an adaptive threshold voltage driver 14, the input of which is connected to the additional output of the function generator 1, and the output connected to the second input of the pulse generator 2, the switch 10 has contacts 15-24. The principle of operation of the device is as follows. The four positions of switch 1 correspond to the measurements of the following intersection characteristics of random processes: the distribution of the durations of the intersection intervals; the distribution of the durations of the intervals containing: a given point in time; the distribution of the durations of the intervals is the inverse of the return time, the distribution of the durations of the intervals is the forward time of the return. 22 The signal under study from the output of the function generator 1 is fed to the input of the pulse driver 2 and to the input of the adaptive threshold voltage generator 14, the output of which is connected to the second input of the pulse former 2. At this, the pulse driver 2 forms short pulses at the moments of intersection (in this case, positive derivative) by a random process of the threshold level formed by the adaptive threshold voltage generator 14. The magnitude of the threshold level is specified in relative units (in this case as a percentage relative to the amplitude value of the signal under study). A series of pulses (intersection pulses) from the output of the former 2 is fed to an inverter 3, which converts it into a series of pulses whose durations correspond to the durations of the intersection intervals, a Square pulse with a duration L from the output of the inverter 3 is fed to the input of the interval-code 4 converter and converted into a burst of pulses, number ha; which is proportional to TT. The received packet of pulses is fed to the counting input of the address counter 5. Preliminarily, a short pulse is applied to the reset input of the address counter 5, which leads to the initial state. The number recorded in the address counter 5, proportional to the duration C, is sent in parallel with the code to the N-input decoder 6 and determines the occurrence of a voltage on the decoder output corresponding to this number. The outputs of the N-output decoder 6 are connected to the first inputs of logic elements AND 7, and the voltage at the i-M output of the decoder serves as a decisive factor for them. At the second inputs of the logrg elements And 7 comes from the output of the differentiating circuit 12 a short pulse that corresponds to the decay of the pulse entering the input of the differentiating circuit 12 and coincides with the end of the time interval to be measured. The outputs of the logical elements And 7 are connected to the inputs of counters 8 and the pulse output from the corresponding logical

element And enters the corresponding pulse counter.

Thus, the incoming pulse is recorded according to its duration in one of the pulse counters 8. At the same time, the duration of the time interval Ja between the Reset and Read pulse is recorded,

When measuring the distribution of the durations of intersection intervals, contact 24 is closed to contact 15, and contact 19 to contact 20. At the same time, from the output of the pulse former, 2 intersection pulses through contacts 24, 15 and delay element 11 are fed to the reset input of the address counter 5. The same The pulses, but not delayed, through the contacts 19, 20 and the differentiating circuit 12 are fed to the first inputs of the logic elements And 7 and are read. In this case, all time intervals between intersection pulses are measured.

When measuring the distribution of durations of intervals containing a given point in time, contact 24 is closed to contact 16, and contact 19 - to contact 21. At the same time, intersection pulses from the output of the pulse former 2 are fed to the input of the delay element 11, and pulses are fed to the input of the differentiating circuit 12 , formed by the trigger 13 with a separate start, with this trigger triggering is carried out by pulses from the generator 9 gating pulses, and stop - the first intersection pulse that follows the gating pulse, the second th trigger input 13 with a split running from the output of shaper 2. From the output of the differentiating circuit 12 to the inputs of the AND gates 7 is fed a short pulse (read) at the time corresponding to the end of the period in which the gate pulse hit. In this case, the durations of only those time intervals between intersection pulses in which gating pulses fall are measured.

When changing the distribution of the durations of the intervals, the inverse return time of contact 24 is closed to contact 17, and contact 19 to contact 22. At the same time, intersection pulses from the output of the pulse former 2 are fed to the input of the delay element, and to the input of the differentiating circuit 12 - gates i.e. gating pulses in this mode are read. The duration of the intersection pulse intervals up to the gate gate is measured.

When measuring the distribution of durations of intervals, the direct return time of contact 24 is closed to contact 18, and contact 19 to contact 23, and a pulse from the generator 9 of strobe pulses is sent to the input of the delay element 11 and the input to the differentiating circuit 12 with trigger 13 with separate start. The duration of the intervals from the gate pulse to the first pulse of intersections is measured.

At the end of the measurement, the i-ro channel counter will show the number of p. Total number of pulses measured p

 n. Density of distribution

emissions are defined by

 -I

(i, -At;

eleven

where u) is the frequency;

At - time interval.

The electrical circuit of the adaptive threshold voltage driver (Fig. 2) contains a rectifier 25, a capacitor 26, a repeater 27, a switch 28, switch contacts 29-31, variable resistors 32 and 33, and a measuring device 34.

The two positions of the switch 28 correspond to the following modes of operation of the circuit: setting the relative value of the threshold level; formation of adaptive threshold level.

First, a relative value of the threshold level is set at which the contacts of the switch 30 and 31 are closed and the reference voltage is applied to the variable resistor 32. The installation is performed by moving the movable

the contact of the resistor 32, the voltage at which is monitored by the measuring device 34 and expressed as a percentage relative to the reference voltage. Thus, between the values of the voltage supplied to the resistor 32 and removed from its moving contact, a percentage ratio is established that is also valid for those cases when a voltage is applied to the resistor 32, the value of which is different from the reference one.

When an adaptive threshold level is formed, the signal enters the input of the circuit, is rectified by the spinner 25, the straightened signal is smoothed by the capacitor. 26, where a voltage is applied to the bending of the signal under study, and is fed to the input of a repeater 27, which prevents the discharge of a capacitor

26 current load, and with repeater

27 through the closed contacts of switch 29 and 31 to the resistor 32 and from the moving contact of the resistor 32 back; 51: to the part of the envelope voltage of the signal under study (adaptive threshold level) goes to the output of the circuit.

Thus, the proposed device due to the use of an adaptive threshold-driver

0 voltage, which is generated by the adaptive threshold level, which varies according to the law of variation of the envelope of the signal under study (monitors the level (amplitude)

5 of the signal under study), which is the predetermined part of the envelope voltage of the signal under study, is achieved unchanged relative to the value of the threshold voltage level from the level (amplitude) of the signal under study when the latter changes in time, leading to a decrease in the spread of the measured intersection characteristics and an increase in the accuracy of determination parameters of the distribution of these characteristics.

Syo3

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Claims (1)

DEVICE FOR MEASURING CHARACTERISTICS OF INTERSECTION OF RANDOM PROCESSES No. 658494, characterized in that, in order to increase the accuracy, an adaptive threshold voltage driver is introduced into it, the input of which is connected to the auxiliary output of the function driver, and the output is connected to the second input of the pulse generator. Figure 1 SU „„ 1185262