SU1607078A1 - Frequency-to-code converter - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used in various devices of frequency automation of power systems. Expansion of functionality is achieved by converting the frequency to both code and voltage, a time interval, and a voltage proportional to the square of the frequency. The goal is achieved by introducing into the device containing a pulse counter 1, a digital-to-analog converter 2, a comparator 5, a generator 4 of the reference frequency, trigger 3, two registers 7 and 10, a device 11 sampling and storing the digital comparator 6 and two dynamic elements 8 and 9 averaging . In this case, all conversion functions are performed on the basis of a single pulse counter and a digital-analog converter for the input frequency period T _x , while eliminating the influence of the discreteness error of the reference frequency generator pulses on the accuracy of frequency to voltage conversion due to synchronization between the formation of a pulse of a calibrated duration T _o and oscillations of the generator of the reference frequency, as well as between the process of dynamic averaging of the formed pulse sequence and the period m input frequency. 1 hp f-ly, 2 ill.

Description

FIG. one

oh; with go-7z and b.

SS ;, ;; ° ro. o ™ ko..ra ™ ra 6 and dh Dygg-oG .se 1 | .ht

- ГПифГоаГ.% О о ™ део «,, ..

l for the period h discrete - GGGG. GG e; a%: ° a. Frequencies for the accuracy of frequency conversion to voltage are achieved due to the presence of synchronization between the pulse shaping process of a calibrated duration and the oscillations of the reference frequency generator as well as between the dynamic averaging process of the generated pulse sequence and the period of the input part. 2 Il.

The invention relates to electrical measuring technology and can be used by various devices of frequency automatics of power systems in the construction of frequency measurement systems.

The aim of the invention is to expand the functional capabilities of the device by converting the frequency to voltage and time interval.

FIG. 1 is a block diagram of the device in FIG. 2 - explanatory diagrams and diagram of the dynamic element averaged Hf N and I

The frequency converter in the voltage and digital code contains the counter 1 pulses of the DAC 2, trigger 3, generator 4 reference frequency, comparator 5, digital comparator 6, memory register 7 and dynamic Elements 8 and 9 averaging, memory register 0 and device 1 sampling and storage. Dynamic elements are implemented on integrator 12 and memory element 13 and switch 14.

The converter works as follows.

in a way.

During one cycle equal to the network period, the device performs five conversion functions. At the beginning of each period of the monitored network, the pulse counter 1 is reset to the zero state. The output of the digital comparator 6 also sets the state "O. With the arrival of the front of the output pulse of the generator 4 of the reference frequency, the trigger 3 is transferred to the state "O", which corresponds to the beginning of the formation at the input of the dynamic element 8 averaging the pulse of the calibrated activity. The output pulses of the oscillator 4 of the reference frequency begin to fill the volume of the counter 1 pulses. The flat comparator 6 compares the output code of the pulse counter 1 with the setpoint code N 2 and at the moment of their equality, the output signal koMnapaTOpa 6 changes to the state "1. With the arrival of the next pulse front of the generator 4 of the reference frequency, the trigger 3 is set to the state "1", which corresponds to the end of the formation at the input of the dynamic element 8 averaging the pulse of a calibrated duration To. In this case, the duration That the generated pulse will be

.T ,, „(1)

0 g - code of the setpoint set to actuation of the digital compressor 6.

Duration That will always consist of the sum of an integer number of periods T, the generato. 4 reference frequencies due to synchronization between the process of forming a calibrated pulse and oscillations of the generator 4 of the reference frequency.

Dynamic averaging element 8 stabilizes the amplitude Uo of a calibrated 30 pulse, extracts the average voltage Ucpi of the generated pulse sequence over one period T. of the monitored network and stores, at the end of each period T, the resulting voltage value equal to

 Uc,., ° - ° UoTof. (2)

T.

As can be seen from expression (2), the output voltage of the UCP-, averaging element 8 O is averaged in proportion to the frequency t of the monitored network.

The dynamic averaging element 8 is executed according to a known scheme based on the integrator 12 and the memory element 13 (Fig. 2). The second input of the memory element 13 is connected to the device input bus 45, which ensures that the averaging interval is equal to the 1x period of the monitored network and allows, if this synchronization is present, between the pulse shaping of a calibrated duration and the generator 4 pulse, the reference frequency is eliminated. reference frequency for frequency to voltage accuracy.

Comparator 5 compares the magnitude of the output voltage of the dynamic element 55 averaging with the output voltage of the DAC 2 and at the moment of their equalization transfers the digital code from the output of the pulse counter 1 to the memory register 7. The value of the code transferred in this case is determined from the expression:

Ij

t. I

Ucp.l TJ- NI, NuAn

Ujut

e uon

supporting

DAC; NuAii - the volume of the DAC. Where, taking into account (2) we get

UoToNbAo N / .-

supply voltage

(four)

As can be seen from expression (3), the code N / transferred to memory register 7 will be directly proportional to the frequency L of the monitored network.

The output of the comparator 5 produces a pulse, the duration of which T will be directly proportional to the frequency of the monitored network.

.(five)

The dynamic averaging element 9 stabilizes the amplitude of the generated pulse and extracts the average value of the voltage Ucp.2 for the period T ;, of the monitored network, the value of which will be equal to

.-sch

Ucp.2 ---. (6)

i X

Where, taking into account (5) we get

WOCLL £ 2

Ucp.2 - rk1,

1dG

where k is the proportionality coefficient. As can be seen from expression (7), the output voltage Ucp.2 of the dynamic element 9 averaging will be directly proportional to the square of the frequency f of the monitored network.

At the end of each period Ti of the monitored network, a digital code value proportional to the period Tx is transferred from the output of the pulse counter 1 to the memory register 10, and the output voltage of the DAC 2, also proportional to the period T, is stored by the storage sampling device 11.

Simultaneously with the start of the next period, the conversion process will begin to repeat.

ten

15

20

Invention Formula

Claims (2)

1. A frequency converter into a code containing a series-connected pulse counter, a digital-to-analog converter and a comparator, a trigger, a reference frequency generator, characterized in that, in order to extend the functionality by converting the frequency into a voltage and a time interval, a digital comparator is entered, a register the memory and dynamic averaging element, the control input of which is connected to the input of the setting in the pulse counter and is the input length, the information input is connected to the output of igger, and the output is the first output width and is connected to the second input of the comparator, the output of which is connected to the control input of the memory register, the output of which is the second output thickness, the counting input of the pulse counter is combined with the trigger synchronization input and connected to the output of the reference generator the frequencies, the outputs of the pulse counter are connected to the corresponding information inputs of the memory register and the first inputs of the digital comparator, the second inputs of which are the reference code bus, and the output is connected to ormatsionnym input trigger. 2. The converter according to claim 1, is distinguished by the fact that, in order to expand its functional capabilities by converting the frequency into a voltage proportional to the square of the frequency, the second dynamic element is introduced into the voltage and code proportional to the period of the controlled frequency. averaging, a second memory register, and a sampling and storage device, the output of which is the third output bus, the information input is connected to the output of the digital-to-analog converter, and the control input is connected to the input bus and to the control course of the second register memory whose data inputs are connected to respective outputs of the counter, and the output is the fourth output line, a second data input of the dynamic averaging element 45 is connected to the comparator output, the control input is connected to the input bus, and the output is the fifth output bus. 40 T X O -: - I i W2.2