SU1239614A1 - Meter of power in ultrasonic frequency region - Google Patents

Abstract

The invention can be used in studies of electroacoustic transducers. The purpose of the invention is to increase measurement accuracy. The meter contains scale transducers 1 and 2, modulators 3 and 4, generator 5, synchronous detector 6 and indicator 7. Introduction to the device of a bandpass filter 8, a phase shifter 9, a discriminator 10 phase shift and the formation of new connections between the elements of the device reduces the influence nonlinearity and partly the phase error of the modulators 3 and 4 on the measurement result. 1 il. (L N9 00; ood

Description

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The invention relates to electrical measuring equipment and can be used for the investigation of: and x electroacoustic transducers.

 The purpose of the invention is higher measurement accuracy,.

The drawing shows a structural diagram of the meter.

The meter contains scale transducers 1 and 2, modulators. 3 and 4, generator 5 is synchronous. a detector 6, an indicator 7, a band-pass filter 8, a phase shifter 9, and a phase shifter 10.

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The inputs of converters 1 and 2 ow - i ;; Characteristics of the filter 8 phase

the meter inputs, and the outputs are connected to the first inputs of the modulators

3 and 4 respectively. The output of the generator 5 is connected to the inputs of the phase shifter 9 and the second by the input of the modulator 3, the output of which is connected via the bandpass filter 8 to the second input of the encoder 4, the control input of the phase shifter 9 is connected to the output of the discriminator 10, and the output is connected to the first input of the discriminator 10 and the control input of the synchronous detector 6, the output of which is connected to the input of the indicator 7 and the input to the output of the modulator

4 and the second input of the discriminator 10.

The meter works in the following way. .

Input signals (voltage and

about ,

current, respectively) is fed to the inputs of converters 1 and 2 where they are scaled to operating 1 levels of modulators 3 and 4, respectively.

The modulator 3 multiplies the signal of generator 5, whose frequency is much higher than the frequency of the input ™ signal of the signal, to the signal received from converter 1. Band-pass filter 8 extracts from the output signal of modulator 3 two components with frequencies equal to 5, respectively, c: t5m and the difference generator frequency

5 and input signal. The amplitude of the selected components is proportional to the amplitude of the first input signal.

and the phase is adequate to its phase. After multiplying in the modulator 4 these components to the second input signal, in the output signal of the modulator 4, the frequency equal to the oscillation frequency at the output signal is 3390/44

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generator 5. The amplitude of this component is proportional to the product of both input signals

cosine of their phase shift, i.e. ak-5tiny power of the investigated circuit. The DC voltage, proportional to the specified value, is injected by the synchronous detector 6 and supplied to the indicator 7. For maximum accuracy of the voltage detection at both inputs of the synchronous detector 6. This requirement and the elimination of the influence of phase frequencies; 1 l on the control input of the synchronous detector 6 is automatically adjusted by the phase: spinner 9 controlled by the discriminator 10.

The proposed meter is more accurately known due to its smaller effect on the measurement result of nonlinearity and, in part, the phase error of modulators 3 and 4 "

Claims (1)

Invention Formula 0 five 0 An ultrasonic power meter contains two modulators, a generator, a synchronous detector, an indicator and two large-scale converters, the outputs of which are connected to the first inputs of the respective modulators, and the inputs are inputs of the generator. It is connected to the second input of the first modulator, the second modulator to the input of a synchronous detector, the output of which is connected to the indicator input, characterized in that, in order to improve the measurement accuracy, a phase shifter and a phase shift discriminator, the first input of which is entered into it connected to the control input of the synchronous detector and the output of the phase shifter, the input of which is connected to the generator output, and the control input to the output of the phase shift discriminator, the second input of which is connected to the output of the second of the modulator, a second input of which is coupled through a bandpass filter with the output of the first modulator " Circulation 728 Subscription