SU1197083A1 - Frequency-to-voltage converter - Google Patents

Abstract

A VOLTAGE FREQUENCY CONVERTER containing the first integrator and a reference frequency generator, the output of which is connected to the clock input of the shift register, the information input of which is the IEE. the house of the device. and the output of the last BOiH of FIG. 1 is connected to the first input of the first element OR NOT, the output of the first integrator is the first output of the device, characterized in that in order to increase the conversion accuracy three inverters are introduced into it, the second and the third .they elements are IPI-NOT and the second integrator, the output of the first bit of the shift register is the connection by the first input of the second: element: OR-NOT and through the first inverter to the second input of the first element OR-NOT, the output of the last bit of the shift register via the second inverto connected to S by the second input of the second element ILIPE, the outputs of the first and second elements (L to STI-NOT connected to the corresponding inputs of the third element OR NOT whose output is connected to the input of the first integrator and through the third inverter to the input of the second integrator whose output is second output of the device. с о X с п п tz Н fO 8

Description

The invention relates to a measuring technique and can be used to convert the output signals of frequency sensors to non-electric values in measuring frequency drivers, in automatic control systems.

The aim of the invention is to improve the accuracy of the conversion by compensating for the constant component of the output signal.

Figure 1 shows the structural diagram of the proposed device; in FIG. 2, timing diagrams.

The frequency to voltage converter contains a 1 exemplary frequency generator, a shift register 2, a first 3 and a second 4 inverters, the first, second and third elements OR NOT 5-7, the third inverter 8, the first 9 and second Yu integrators, the outputs of which are respectively the first 11 and the second 12 outputs of the device.

The frequency to voltage converter operates as follows.

From the generator output t exemplary frequency to the clock input of the shift register 2 receives a pulse sequence with a frequency p (Fig.2A). From the device input to the information input of the shift register 2 receives a sequence of pulses of the converted frequency i (Fig.26). At the output of the first bit of the shift register 2, the first sequence of convertible frequency pulses is obtained — f synchronized with the pulses of the generator 1 of the exemplary frequency, which is fed to the input of the first inverter 3 and the first input of the second element ILINE 6 (FIG. 2B). From the output of the first inverter 3, the inverted sequence is fed to the first input of the first element OR NOT 5 (FIG. 2d). From the output of the last bit of the shift register 2, the second sequence of pulses of the converted frequency f, shifted from the first by a time multiple of the oscillation period of the generator 1 of the exemplary frequency, is fed to the input of the second inverter .4 and the first input of the NE element OR NOT 5 (Fig. 2d) the output of which of these two sequences of synchronized input pulses is formed

the first sequence of pulses of constant duration i (j, multiple to the oscillation period of the generator 1 of exemplary frequency, following with the converted frequency i (Fig. 2e). The duration of the generated pulses is determined by the expression

h (K-OTO,.

where K is the shift register shift 2;

TQ - oscillation period of the generator 1 exemplary frequency. This sequence is fed to the first input of the third element IPI-NE 7. From the output of the second inverter 4, the inverted second sequence of synchronized pulses of the frequency being converted is fed to the second input of the second element SH-NOT 6 (FIG. 2G), the first input of which receives the non-inverted first synchronized sequence input pulses From these two pulse sequences at the output of the second element OR NOT 6 a second sequence of pulses of constant duration iu (K-1) TQ is formed, the trace with a convertible frequency 1- (fig.2z) This sequence of pulses of constant duration t (j, is shifted relative to the first one by equal to half the follow-up period Tj (input pulses, is fed to the second input of the third element OR-HE 7, at the output of which pulses of duration i are obtained from these two sequences

.- - (K.-1) Td, following with a double convertible frequency 2, which are fed to the input of the third inverter 8 and the input of the first integrator 9 (Fig. 2i). From the output of the third inverter 8 is removed, a sequence of pulses of constant duration iy (K 1) 0 J following with a double convertible frequency 2i, and fed to the input of the second integrator 10 (Fig. 2k). At the output of the first integrator 9, a voltage is obtained, the average value of which is determined by the expression

U, KU, l-2 (,.

This voltage is applied to the first output 11 of the device (Fig. 2). At the output of the second integrator 10, a voltage is obtained. The mean value of which is determined from BE 1

(K-OT ,.

The voltage Ug arrives at the second output 12 of the converter (Fig. 2m). The output voltage of the converter, equal to the difference of the voltage O, and U, is removed from the outputs 11 and 12 (fig.2n). This voltage is

, + su,

where and; K UoJl-4 (-constant component of the output voltage of the converter;

SUx - 4KU K-i) (MfxuTo U, D-4 (K-l)) Toi) (increment of the output voltage of the converter in the most general case, due to the change in all quantities; Tdd is the nominal value of the oscillation period of the reference frequency generator;

Kg is the nominal value of the integrator transfer coefficient;

Uj is the constant component of the integrator power supply} i is the carrier frequency of the converted frequency-modulated HCM) signal;

uiy - the devia of the converted clockX

then you;

DK, and,., ТТ - deviations of the values of K, (JjjjTp, respectively, from the nominal values.

If one chooses the width K of the shift register 2 and the value of the period T of oscillations of the generator 1 of the reference frequency in such a way that the condition

4 (K-OT G,

ABOUT

then the constant component U in the output voltage of the converter will vanish and the output voltage of the converter is determined only by the deviation of the frequency to be converted, i.e.

Ux-8Ux -4 UotK-i) Tobi, -4KUo (K-tUxobo,

which allows you to select very small deviations of the frequency to be converted and to obtain a high accuracy of the conversion of the input signal.

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Claims (1)

A VOLTAGE FREQUENCY CONVERTER containing a first integrator and a reference frequency generator whose output is connected to the clock input of the shift register, the information input of which is the input of the device, and the output of the last discharge is connected to the first input of the first OR-HE element, the output of the first integrator is the first output of the device , characterized in that, in order to increase the accuracy of the conversion, three inverters, the second and third elements OR — NOT and the second integrator, the output of the first discharge of the shear p the register is connected by the first input of the second OR-HE element and through the first inverter to the second input of the first OR-CE element, the output of the last discharge of the shift register through the second inverter is connected to the second input of the second ORINE element, the outputs of the first and second elements IPI-NOT connected to the corresponding inputs of the third element IPI-NOT, the output of which is connected to the input of the first integrator and through the third inverter to the input of the second integrator, the output of which is the second output of the device. S and 1197083 FIG. I> 1 1197083 2