SU570852A1 - Sound and infrasound frequency phase calibrator - Google Patents

Description

one

Haodptjenne can be used to accurately set phase shifts when calibrating infrasound and sound frequency phase meters.

A pyrotechnic device for discrete reproduction of phase shifts 1 is known, comprising a clock pulse generator connected via matching circuits to identical variable and reference phase channels, each of which includes a series-connected trigger, a low-pass filter and an output amplifier with an attenuator, in addition a clock generator through a delay line, a pulse counter, a decoder, and a switch are connected to the second input of the variable phase channel matching circuit.

However, such a device can work only at fixed frequencies, and when switching from one operating frequency to another, it is necessary to change the filters, each of which includes several notch links; Moreover, it is difficult to obtain output signals with a low level of non-linear distortion.

The purpose of the invention is to reduce the level of nonlinear distortion and expand the frequency range towards infra-low frequencies.

This is achieved by the fact that the phase calibrator has sound and infrasonic frequencies containing identical variable and reference phases, each of which contains an output amplifier with an attenuator, the input of the reference phase channel being connected directly to the generator and the variable phase channel through the coincidence circuit, the second input of the coincidence circuit through the trigger is connected on the one hand to the reset circuit, and on the other, through the comparison circuit of the codes to the outputs of the phase master, the following are entered into the channels of the reference and variable phases two reversible counting decades and two triggers, code-voltage converters, sequentially

connected adder, low-pass filter, inverter and electronic switch, as well as a non-switch, a matching cascade and a reference voltage source, connected to the power inputs of two entered code-voltage transducers, and a similar input of the third of the above-mentioned converters through a switch and a matching cascade associated with the output of the first one, while the outputs of the channel trigger

Claims (2)

the reference phase is connected to the code comparison circuit, and the reset channels of both channels are connected to the reset circuit, the informational outputs of the reversible counting decades through the code-voltage converters and the series-connected adder, low-pass filter, inverter and electronic switch are connected to the output amplifier and not | Mediocre to a code comparison scheme. The drawing shows a functional diagram of the proposed phase calibrator and infrasound frequencies. The first channel I of the phase calibrator contains low-pass filter 1, operational amplifier (inverter) 2, electronic switch 3, output amplifier 4, attenuator 5, reversible counting decades 6, 7, triggers 8, 9, adder 10, matching cascade 11, converters 12 , 13, 14 code-voltage, reference voltage source 15, switch 16. In addition, the phase calibrator contains 17 clock pulses, a coincidence circuit 18, a code comparison circuit 19, a phase adjuster 20, a reset circuit 21, a trigger 22, a second Channel P. The principle of operation of the phase calibrator is in obtaining output voltages whose instantaneous values are a function of codes. Let in each channel of the phase calibrator two countable reverse decades 6 and 7 and two flip-flops 8 and 9 are sequentially included. Trigger 8 reversals decades 6 and 7, and flip-flop 9 controls the operation of the electronic switch 3 and thereby connects the amplifier 4 to positive, then negative half-period of voltage. The outputs of the triggering counts of decade 6 and 7 are directly or via a decoder (not shown in the diagram) connected to the electronic keys of the code 12 transducers 12, 13, and 14, and the output signals of the transducers 12 and 13 through the corresponding weight resistors enter the adder 10. Calibrator phases can produce signals varying in sinusoidal, sawtooth and other laws with discrete phase shift. Consider the mode of operation of the calibrator in the formation of sinusoidal output signals. The code-voltage converters 13 and 14 are powered from the source 15 of the reference voltage and produce output step signals varying according to sinusoidal and cosine-like laws with a phase resolution of 10 °. Instead of the voltage from the source 15 of the reference voltage to the converter 12, the output voltage of the code-voltage converter 14 is supplied through the matching cascade And and the switch 16, which determines the slope of the signal of the adder 10. After the pulse of the reset circuit 21 arrives at the counting decades 6 and 7 and triggers 8 and 9, the calibrator is set to sum mode. When the 90th pulse arrives from the generator 17, the trigger 8 is thrown and puts the counting decades into subtraction mode, and the 180th pulse returns the trigger 8 to its initial state and simultaneously triggers the trigger 9. The output signal of the adder 10 is smoothed by the low-pass filter 1 and is inverted. an amplifier 2. The electronic switch 3, controlled by trigger 9, generates a bipolar signal from two unipolar signals. The second channel of the phase calibrator has a similar construction. The required value of the phase shift between the output signals is set using the phase adjuster 20, the output voltages of which in binary-decimal code are fed to the first inputs of the comparison circuit 19. When the Reset button is pressed, the circuit 21 generates a short pulse, with which all the phase calibrator triggers are set to the zero state. The coincidence circuit 18 closes and the clock pulses of the generator 17 do not arrive at the counter of the second channel. As soon as the code of the first channel of the calibrator compares with the code of the phase setter, circuit 19 generates a pulse, which flips trigger 22 to the operating state and removes the prohibition from circuit 18 of coincidence. From this point on, the phase calibrator already produces two signals with the required phase shift. If switch 16 is put in a different position, then the output signals will vary linearly. The metrological characteristics of the phase calibrator are determined by the speed and accuracy of the converters 12, 13, 14, as well as by the frequency stability of the oscillator 17. The last requirement is not difficult, the stability and accuracy of the frequency setting can be very high. The accuracy of setting the phase shift in the calibrator is improved by reducing the nonlinear distortion coefficient of the output voltages, and at lower frequencies this is easier to implement and only an increase in the number of counting decades and associated converters is required. The use of unified nodes and integrated circuits in the calibrator allows to increase reliability and simplify it. Claims of sound and infrasonic phase calibrators containing identical channels of the variable and reference phases, each of which contains an output amplifier with an attenuator, the input of the reference phase channel being connected directly to the clock generator, and the variable phase channel through the coincidence circuit, the second input The trigger circuit is connected from one side to the reset circuit through the trigger, and on the other, through a comparison of the codes to the outputs of the setter of the basics, characterized in that, in order to lower the level of nonlinear distortions and increasing the frequency range in the direction of the frequency range, two counted connected decade series and two flip-flops, code-voltage converters, a series-connected adder, a low-pass filter, an inverter and an electronic switch, as well as a switch matching cascade and reference voltage source connected to the power inputs of two of the entered code-type converters, and a similar input of the third of the named converters through the switch and matching stage is connected with the output of the first one, while the outputs of the trigger channel of the reference phase are connected to the code comparison circuit, and the reset buses of both channels are connected to the reset circuit, and the information outputs of the reversible counting decades through the code-voltage converters and serially connected an adder, a low-pass filter, an inverter, and an electronic switch are connected to the output amplifier and directly to the code comparison circuit. Sources of information taken into account during the examination 1. USSR author's certificate No. 261573, cl. G 01R 25/04, 21.06.68.