SU1509753A1 - Apparatus for measuring the frequency of electric signal - Google Patents

Abstract

The invention relates to a measurement technique and can be used to automatically process signals of frequency transducers, as well as to measure the frequency of electrical signals at adjacent time intervals. The purpose of the invention is to improve the measurement accuracy. The device for measuring the frequency of an electrical signal contains a counter 3 of the number of periods, a counter 4 of the duration of the period, a register 5 of memory, a divider of 6 codes. Introduction of the trigger 1 control and the AND 2 element allowed reading the information from the output of the counter 4 of the period duration not in the dynamic but in the static mode of storing information about the duration of a part of the period. 2 Il.

Description

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The invention relates to a measurement technique and can be used to automatically process signals of frequency transducers, as well as to measure tiacTOTH electrical signals at adjacent time intervals.

The purpose of the invention is to increase the measurement accuracy.

FIG. A block diagram of the device is shown, FIG. 2 - time diagrams that show his work. .

The device contains a trigger 1 control, the element And 2, the counter 3, the number of periods, the counter 4, the duration of the period, p (register 5 memory and deligel 6.

The measured frequency arrives at the reset input to the trigger trigger 1, and the start pulse of the measurement interval is received at its input to the unit. The output of trigger 1 of control is connected to the first input of element I 2, to the second: the input of which serves the reference frequency f, while the counting input of counter 3 of the number of periods is connected to the reset input of control trigger 1, the installation of which is combined with the inputs of the counter of 3 numbers periods; and counter 4, the duration of the period, register clock 5 memory n divider 6. The counter 3 output of the number of periods is connected to the information input p.eTKCTga 5 lam9, the type of which (pin n) is connected to the input of the divider 6, and the output of the element 2 is connected to the counting input of the counter 4, the duration of the period, the output of which (thickness m) is connected to the multiple input of the divider 6.

The device works as follows.

The pulses Tj, the beginning of the measurement interval, synchronized with the pulses of the reference frequency, have a duration equal to the duration of the pulse of the reference frequency and a period of appearance equal to T K t, where

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ъ 7 is the period duration of the reference frequency, Kg is the specified number of pulses of the reference frequency.

The occurrence of the next pulse Td of the beginning of the measurement interval leads, along the pulse front, to remembering the state of the counter 3, the number of periods from

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five

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the measured frequency in register 5, and by the pulse decay - to set to zero the counters 3 and 4 and to set the trigger to 5 Ija 1 control (unit of resolution for determining the duration of the period of the measured frequency).

 the same pulse of the beginning of the measurement interval initiates a divider 6 for 0 reading with time delay information from register 5 and counter 4.

The enable signal generated by control trigger 1 opens element 2 for passing pulses of 5 reference frequency f to counter 4 for the duration of the period that counts these pulses. The first pulse of the measured signal f, after passing through the decay of pulse T, by its front translates trigger 1 of control into zero. At This, the resolution signal from the output of the trigger 1 is removed, which prohibits the passage of the pulses of the reference frequency through the element 2 to the counter 4. The remaining pulses of the measured signal fj (only confirm that the trigger 1 is set to zero.

Thus, in the counter 4, a code T is formed, corresponding to the number of pulses of the reference frequency, placed on the enabling signal Q, equal to the duration of the part of the first, period of the measured frequency, which falls within the reference interval. The generated code is stored in counter 4 until the beginning.

The next measurement interval. In this case, the part of the period of the measured frequency turned out to be determined with an accuracy of one pulse of the reference frequency, the value of which is many times greater than the maximum value of the measured frequency. An increase in the value of the reference frequency leads to an increase in the measurement accuracy at the same measurement interval.

At the beginning of each measurement interval, the value of the counter 3 is stored in the register 5 of the memory of the number of periods, and then the counter 3 is set to: zero. After that, the counter 3 begins to count the pulses of the measured signal f, and by the end of the measurement interval, a code n is formed in it, the number of pulses of the measured frequency that fall into this measurement interval.

Divider 6, receiving a request to read information and wait a time equal to the maximum duration ne5

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of the measured frequency, polls the register 5 and counter 4, and calculates the frequency value in the i-th interval of temperament

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f frequency of the measured signal;

the duration of the period of the measured signal i the number of pulses of the measured signal that fell into a given measurement interval, the number of pulses of the reference frequency placed on the enabling signal Q of the previous measurement interval}

the number of reference frequency pulses stored. on the resolution signal O of the given measurement interval, the reference frequency.

Introduction to the trigger control device 1, and the And 2 element allows: to use counter 4 both in the counting mode and in the storage mode, which makes it possible to read information from the counter in static mode, and not in the mode of rapidly changing codes, but also increase the value of the reference frequency.

Claims (1)

Invention Formula An apparatus for measuring the frequency of an electrical signal, comprising serially connected counter of the number of ierodes, whose input is the input of the device, register: memory and divider, as well as the period duration counter, the input of which combined with the input of the measurement interval of the device, the reset input of the counter of the number of periods and the synchronization of the register of the memory and the divider, which is due to the fact that, in order to improve the measurement accuracy, sequentially connected control trigger And element, the second input of which is connected to the input of the reference frequency of the device, and the output is connected to the input of the period duration counter, while the reset input of the control trigger is connected to the input of the device, the installation input of the control trigger is connected to the reset input of the counter ka number of periods, and the output of the counter period duration is connected to the second input of the divider. B c