SU1322175A1 - Device for measuring non-linear distortions of generators of frequency-modulated oscillations in stereo mode - Google Patents

Abstract

The invention relates to the field of measurement technology. The purpose of the invention is to increase the resolution of the measurement of the distortion of the stereo signal in the generator of FM oscillations. The device contains sources 1 and 9 of modulating voltage, stereo modulators 2 and 12, meter 4 frequency deviation, stereo decoder 5, selective indicator 6, adder 8; phase shifters 10 and 14, attenuators P and 15, generator 13 FM oscillations. To achieve this goal, an adder 7 is inserted into the device and new functional connections are formed. 1 il. i ate Yuo Yu p i - cn

Description

13

This invention relates to a measurement technique.

The purpose of the invention is to increase the resolution of the measurement of the distortion of the stereo signal in the generator of frequency-modulated oscillations.

The drawing shows the structural scheme of the proposed device.

The device contains a source of modulated voltage I, a stereo modulator 2, a frequency modulated oscillator under study 3, a frequency deviation meter 4, a stereo decoder 5, a selective indicator b, a sum 7 and 8, a modulating voltage source 9, phase shifting (2л 10, P.'s attenuator, stereo modulator 2, oscillator 13 frequency-modulated oscillations, phase shifter 14 and attenuator 35,

In the device, a source 1 of modulating voltage, an adder 7, and a stereo module are connected in series. Torus 2, frequency modulated oscillator 3, frequency gauge 4, stereo decoder 5, adder 8 and selective indicator 6e, the output of modulating voltage source 1 is connected via a serially connected phase shifter 14 to attenuator I5 with the second input of adder 8. The source 9 of the modulating voltage NIL is connected to the input of the adder 7 and through serially connected phase shifter 10, attenuator 11, stereo modulator 12 and generator 13 of frequency-modulated oscillations connected to the heterodyne input of meter 4 deviations frequencies, with the second input of the stereomodulator 12 connected to the output of the subcarrier frequencies. stereo module 2.

The device operates as follows.

 With the help of two sources 1 and 9 of modulating voltage and adder 7

in a stereomodulator 2, form a cosiness of a complex stereo signal modulated by two tones. This signal is fed to the modulating input of the generator 3 of frequency-modulated oscillations to measure the harmonic coefficient of this generator in stereo mode. From the output of the generator 3, the test oscillation is fed to the input of meter 4 of the frequency deviation and stereo decoder 5, the output of which is modulated

with

W 15 0

25-30 35 0

five

-

0

752

common voltage. At the same time, the oscillation from the output of generator 13 of frequency-modulated oscillation J in the frequency modulation law of which the stereophonic oscillation generated by modulating voltage source 9, phase attenuator P 1 and stereo modulator 12 the initial phase of the subcarrier frequency at the output of which coincides with the initial phase of the subcarrier oscillation of the main stereo modulator 2,

The amplitude and initial phase of the stereo oscillation envelope are selected using a phase shifter 10 and an attenuator 11 so as to compensate for one of the main modulating oscillations of the complex stereo signal in the frequency-modulated oscillation at the input of the meter 4 frequency deviations. Thus, through the last and stereo decoder 5 passes stereo oscillation, modulated by only one of the main tones. The measurement of the harmonic coefficient of the generator being tested is carried out according to the results of the measurement of the combinational components at the output of the stereodecoder 5 using the selective indicator 6.

Since the formation of the combinational components of the two modulating frequencies requires the presence of both basic frequencies in the modulation law of the complex stereo signal, in the 4 frequency deviation meter and in the stereo decoder 5 the combinational components do not occur even if these blocks have a significant level of their own nonlinear distortions. The measured combinational components occur only in stereo modulator 2 and generator 3 of frequency modulated oscillations.

The proposed meter does not contribute to the measured value, which allows to achieve the purpose of the invention, Phaser 14, attenuator 15 and adder 8 are needed to compensate for the second main modulating frequency at the input of the selective indicator 6, which significantly increases the dynamic range of the selective indicator and increases the resolution measuring ability of the device.

313221754

Claims (1)

Claims swarm phase shifter and second attenuator, A device for measuring the nonlinear output of which is connected to the second distortion of the DOM frequency generators of the first adder, the second stereo7 modulated oscillations in a stereo modulator, the output of which is unbalanced, containing in series a 5 meter frequency deviation the common first source is modulated-connected to the terminals for connecting the source voltage, the first phase shifter of the generator being followed, distinguishes the first attenuator, the first stereo with that, with the aim of raising the amplifier, the frequency-modulated frequency generator, oscillations, the devia meter, a second adder is entered, the inputs frequency, stereo decoder, the first of which is connected to the outputs of the source and the selective indicator, modulating voltages, and subsequently connected to the second output is connected to the input of the second stereo source of the modulating voltage, the second modulator.