SU1725149A1 - Device for measuring ratio of frequencies of pulse sequences - Google Patents

Abstract

The invention relates to a pulse technique and can be used to measure the ratio of the frequency of following statistical sequences of pulses. The device contains reversible counters 3, 4, the element OR b, the elements And 7-11, the generators 10, 12 single pulses, the input bus 1, 2. 1 Il.

Description

The invention relates to a pulse measurement technique and can be used to measure the ratio of the frequency of following statistical sequences of pulses.

The purpose of the invention is to expand the range of measurement of the frequency ratio of a sequence of pulses.

The drawing shows a block diagram of an apparatus for measuring the frequency ratio of a pulse train.

The device for measuring the frequency ratio of the pulse sequences contains two input buses 1 and 2, reversible counters 3 and 4, a code-controlled frequency divider 5, the counting input of which is connected to the first input bus 1, and the information inputs are connected to the information outputs of the reversible counter 3, the element OR 6, the elements 7–9 and the first generator 10 of a single pulse, the subtracting input of the reversing counter 4 is connected to the second input bus 2, its summing, the input to the output of the co-controlled frequency divider 5, these inputs are bitwise with information outputs of the reversible counter 4, the output of direct transfer is with the first input of the first element AND 7 and the first input of the element OR 6, the output of the reverse transfer with the first input of the second element AND 8 and the second input of the element OR 6, output which is connected to the synchronization input of the recording of the reversible counter 4, the output of the third element And 9 is connected to the output of the first generator 10 of a single pulse, the output of which is connected to the second inputs of the first 7 and third 9 elements And, and the output of the first element And 7 Inonii a summing input of down counter 3, the output of second AND 8 - a subtraction input of down counter 3 pulses, whose output is the output device. In addition, the device contains the fourth element And 11 and the second generator 12 of a single pulse, and the output of the fourth element And 11 is connected to the input of the second generator 12 of a single pulse, the output of which is connected to the second inputs of the second 8 and fourth 11 elements And, the first input of the last connected to output reverse transfer reversible counter 4, the output of the direct transfer of which is connected to the first input of the third element And 9.

The device works as follows.

The sequence of pulses divisible with a frequency f1 through the input bus 1

arrives at the counting input of the code-controlled divider 5 frequency, and the sequence of pulses of the divider with frequency f through the input bus 2 - to the subtractive

reversible counter input 4.

In the steady state measurement, i.e. in the mode in which the average values of the frequencies fi and f2 remain unchanged, the code of the number Q (t) at the information outputs

0 counter 4 is in the range from 0 to Omax, where Omax is the capacity of counter 4; t - the value of the current time. From the information outputs of the reversible counter 3, the code of the number K is output.

5 and to the information inputs of the code-controlled frequency divider 5, the number K determining the division factor of the code-controlled frequency divider 5. Since pulses with a frequency fi arrive at the counting input of the code-controlled frequency divider 5, a sequence of pulses is formed at its output

 -t

5B steady state measurement

the number K determines the ratio

hg h

Whence it follows that in the steady state

0 mode

fll f2.

Since the subtractive input of counter 4 receives pulses with a frequency f2, and the summing input receives pulses with a frequency fn with

5 of the output of the codoobranch divider 5 frequency, then with deterministic frequencies fi and f2, the state of the counter 4 changes only within one pulse, which is due to the presence of a phase shift

0 between frequencies f2 and fn. Typically, the capacity of the reversing counters 3 and 4 is set to not less than 10 pulses, due to the design of integrated circuits commercially manufactured by the industry.

5 Therefore, the oscillation of the state of the counter 4 within one pulse does not cause signals. At its outputs, forward and reverse transfer and the state of the counter 3 remains unchanged. Unchanged remains 0 s and the chils code K at the output of the counter 3.

When changing the average value of the frequencies fi and f2 or the average value of one of them, i.e. when the device operates in a transient mode, the equality is violated and, therefore, more pulses are sent to one of the counting inputs of counter 4 than to the other. The state of counter 4 begins to change either upwards or downwards accumulated

until one of the outputs of the direct or reverse transfer does not give rise to a pulse. This pulse through the element OR 6 enters the synchronization input of the record of counter A and, with its leading edge, records the code Q (t) arriving at its information inputs from its information outputs. At the same time, a change in the code at the information outputs of counter 4 at the back edge of the input pulse is blocked and the limit state of counter 4, which corresponds to the code of the number 0 0 or Q Omax, is maintained until the direction of accumulation of pulses in the counter changes 4. After the counter 4 reaches one of the limit states, each high frequency pulse uncompensated by a low frequency pulse is repeated at the corresponding transfer output. The same pulse through the first input element And 9 or through the first input element And 11, respectively, is fed to the input of the generator 10 or to the input of the generator 12, with the result that the generators 10 or 12 produce a pulse of a certain duration. Moreover, a pulse from the output of the generator 10 through the second input of element 7 blocks the passage of pulses (except the first) from the output of direct transfer of counter 4 to the summing input of counter 3 for a time equal to its duration, similarly to the pulse from the output of generator 12 through the second input of element AND 8 blocks the passage of pulses (except the first) from the output of the reverse transfer of counter 4 to the subtracting input of counter 3 for a time equal to its duration.

At the end of the specified time, the blocking is removed, and the first impulse from the forward or reverse transfer output of counter 4 is supplied through the first inputs of AND 7 or 8 elements, respectively, to the summing or subtracting input of counter 3, the subsequent arrivals of impulses from the direct or reverse transfer output 4, respectively, to the summing or subtracting input of the counter 3 is again blocked by a pulse generated by the generator 10 or 12, respectively.

Elements 9 and 11 prohibit the passage of pulses from the outputs of the forward and reverse transfer of counter 4, respectively, to the inputs of generators 10 and 12 for a time equal to the duration of the pulse generated by these generators.

The pulses coming from the outputs of direct or reverse transfer of counter 4 through the first inputs of elements 7 or 8, respectively, to the summing or subtracting input of counter 3, change the code at the information outputs of the last and at the information inputs of the frequency divider 5.

Changing the code at the information inputs of the coding control frequency divider 5 causes the frequency fn to change at the output of the coding control frequency divider 5 so that the imbalance between the frequencies fn and f2 at the counting inputs of counter 4 decreases. This process is repeated until the state of counter 4 satisfies the condition

Q Q (t) Relish,

whereupon the established measurement mode occurs. At the same time, there are no pulses at the summing and subtracting inputs of counter 3, and the output code of the number K of counter 3 remains unchanged.

The magnitude of the random component of the measurement error, especially when measuring the ratio of the frequency of following statistical sequences of pulses, is required by selecting the pulse duration generated by generators 10 and 12. With variations in the frequencies fi and f2 that are fluctuating, at the outputs of the forward or reverse transfer counter 4 a pulse train appears. However, only a part of these pulses passes to the corresponding summing or subtracting input of the counter 3, in the optimal case no more than one. The passage of the remaining pulses to the summing or subtracting input of the counter 3 is blocked by a pulse generated by the generator 10 or 12.

Claims (1)

Invention Formula A device for measuring the frequency ratio of pulse sequences, containing two input buses, the first and second reversible counters, a code-controlled frequency divider whose counting input is connected to the first input bus, and the information inputs are connected to the information outputs of the first reversible counter, OR element, first, second and third the elements And the first generator of a single pulse, and the subtracting input of the second reversible counter is connected to the second input bus, the summing input of the second reversing account snip connected to the output kodo- controllable frequency divider, the second data inputs of the reversible counter are connected bitwise with an Information outputs a second down counter, the output direct transfer of the second up-down counter connected to the first input of the first AND gate and the first input element OR, the reverse transfer output of the second reversible counter is connected to the first input of the second element AND and the second input of the OR element, the output of which is connected to the synchronization input of the second reversible counter recording, the output of the third element AND is connected to the input of the first generator of a single pulse, the output of which connected to the second inputs of the first and third elements And, and the output of the first element And is connected to the summing input of the first reversible counter, the output of the second element And is connected to the subtract yuschim reversing input of the first pulse counter output koto0 is the output of the device, which is so that, in order to expand the measuring range of the frequency ratio of a sequence of pulses, a fourth And element is entered into it, and a second single pulse generator, and the output of the fourth And element connected to the input of the second generator of a single pulse, the output of which is connected to the second input of the second element And the second input of the fourth element And, the first input of which is connected to the output of the reverse transfer of the second reversible counter, the output of the direct transfer of which th is connected to the first input of the third element I.