SU765740A1 - Analogue converter of relative frequency difference - Google Patents

Description

t

The invention relates to a measuring technique, in particular to frequency automation and control systems, and is intended to obtain a constant voltage proportional to the relative frequency difference between two pulsed streams.

A device containing pulse shapers, keys, a pulse generator and a counter fj is known.

The disadvantages of it are the complexity and lack of analog output.

The closest known to the invention is a meter of a small relative difference of two pulse frequency, containing a block for allocating a differential frequency, a unit for alternately forming two frequency pulses, keys, logic circuits, trigger frequency dividers and a bridge differential frequency converter 2. The principle of operation of the specified converter is based on converting the selected absolute difference of two frequencies into an analog signal using a bridge converter, the corresponding powering of which ensures the proportionality of the output signal to the relative difference of the compared frequencies.

The disadvantages of this device are its complexity and great inertia.

The purpose of the invention is to simplify the device and increase its speed.

10 This is achieved by integrating an adder and an adder, the first input of the adder is connected to the DC bus and the first input of the key, the second input is entered into the device containing the period former and the key, the control input of which is connected to the output of the period former. which is connected to the integrator output and

20 second input of the adder, the output key is connected to the input of the integrator. Figure 1 shows the structural diagram of the proposed Converter; 2 shows timing diagrams for the operation of the device.

The converter consists of a 1-period former, a key 2, an integrator 3, and s / mmator 4.

The converter works in the following 30IIM way.

Shaper l produces periods of two consecutive signals following each other. For the duration of one of these, T ,, the source voltage U is connected to the integrator input (j, during the same periods the integrator input is supplied to its output voltage. In the pauses between pulses, key 2 is open and the integrator operates in memory mode. Since the integrator is implemented on the basis of a DC inverting amplifier, the output voltage of the integrator 3 is opposite in sign to the voltage UQ of the source, and during the action of period T the integrator capacitor is charged, and during the action T of its discharge. The time interval of the integrator's time is much greater than the periods f, 1 the voltage at its output does not change at the time of the operation of each of them. This means that in the steady state the charge received by the integrator capacitor is equal to the one lost and at output 3 there is a constant voltage satisfying the relation

,

from here

U

and. Ot

The adder 4 produces the summation of the voltages UQ U, which (taking into account the sign U {) gives the value of the output voltage of the device

UBb.x Uo-Uo U b :: 2, U, proportional to the relative times i, -f,

frequency

one

,

i.

 Where

  g FIG. 2 b indicates the key output 2, forming a signal

integrator from wo tension. Here, for the sake of consistency, the shape of the integrator voltage pulsation is shown on an enlarged scale. The amplitude of the pulsation is determined by only one ratio between the duration of the periods and the constant time of the integrator and does not depend in any way on the relative position of the periods and their ratio, which is determined by the use

Q memory mode integrator (see Fig.2). Thus, the time constant of the integrator is calculated only from the required suppression of the pulsations, determined by the frequencies being compared, and not by their difference, as

 in a known device.

This provides a significant increase in speed. Moreover, in the proposed converter, approximately three times less equipment is used than in the known device, i.e. The voltage device is much simpler known.

Claims (1)

1. Authors certificate of the USSR 324586, cl. 01K23 / 10, 1970.2. Author's certificate of the USSR 307981, cl. С; 01К23 / 06, 1969. Vm31 , tto