SU1265637A1 - Calibration oscillator of complex signal normalized by harmonic factor - Google Patents

Abstract

The invention relates to a device for generating a signal with a given harmonic coefficient and can be used in radio measuring equipment for testing nonlinear distortion meters. The purpose of the invention is to improve the accuracy of the specified harmonic coefficient. achieved due to the fact that mixers 4 and 5, a front modulator 3, filter 6 lower ones were inserted into the device containing the generator 1 of the sinusoidal signal and the attenuator 2, Oi 00 sl

Description

Frequency, filter 9 intermediate part of the fundamental limits on the tots, controlled and reference oscillators 7 and 8 and the phase detector 10. As a result, the device is not available1265637

frequency range. In this case, the output signal can have values of tens and hundreds of megahertz. 1 il.

The invention relates to a device for generating a signal with a given harmonic coefficient and can be used in radio measuring equipment for testing nonlinear distortion meters.

The purpose of the invention is to improve the accuracy of the specified harmonic coefficient.

The drawing shows a block diagram of the device.

The device contains a sinusoidal signal generator 1 with an attenuator 2 connected to it, as well as a phase modulator 3, mixers 4 and 5, a low-pass filter 6, a controlled oscillator 7, a reference oscillator 8, an intermediate frequency filter 9 and a phase detector 10. The output of the attenuator 2 is connected in series with the phase modulator 3, the mixer A and. low pass filter 6, the output of which is the output of the entire device; another input of the phase modulator 3 and. the input of the mixer 5 is connected to the output of the controlled generator 7, the other inputs of the mixers 4 and 5 are connected to the reference generator 8, and the control input of the controlled generator. A rator 7 is connected to a phase detector 10, one input of which is connected to the output of a sinusoidal signal generator 1, and another input of a phase detector 10 through an intermediate frequency filter 9 connected to a mixer output 5.

The device works as follows.

I

Sine-wave generator 1 generates voltage U (t) sinsit with frequency P, which is fed to the input of attenuator 2 and phase detector 10. Phase detector 10, controlled generator 7, reference generator B, mixer 5 and intermediate frequency filter 9 phase lock ring on secondary beats

The signal of the controlled generator 7 U (t) coso3ypt and the reference generator 8 Ug (t) coscolot, respectively, arrive at the second and first inputs of the mixer 5, the output of which beats with the difference frequency uQ Qg-c3, jp. The beat voltage is fed to the input of the intermediate frequency filter 9, which extracts from the result of multiplying the reference signals

8 and 7 generators controlled by the signal of the difference frequency Uo (t) cos (co-ODyr) t, which is fed to another input of the phase detector 10. As a result, a control voltage is generated at the output of the latter, which is fed to the control input of the controlled generator 7, introducing corrective detuning and ensuring equality & Eo-co.

The signal from the output of the controlled generator 7 is fed to the input of the phase-modulator 3, to the second input of which voltage is supplied from the output of the attenuator 2. At the output of the phase modulator 3, a signal is generated

U, j (t) cosCcOu t + msinnt),

where m s / k}

S is the slope of the modulation characteristic of the phase modulator 3J

K - attenuation coefficient of attenuator 2.

This signal is fed to the input of low-pass filter 6, which suppresses the total product, converts and extracts the differential. As a result, at the output of the 6 frequency filter, the signal looks like

Ug ((cOg-6D) t-msin it,

substitutions OQ - CDuf have Ug, (t) cos (szt-m)

This signal is the output signal of the oscillator-calibrator, its spectrum contains harmonics of the frequency L. The decomposition of the output signal in the Fourier series is

U6bu (t :) I, (m) - | - | 1 „„ (t) - (-1) - In., (M) dosnsj.t,

where n is the harmonic number.

 The harmonic factor of such a signal is determined as follows. Practically, the value of n is taken to be no more than 10. To change K in the range of 0-100%, the value of m is required to vary from 0 to 2.

It can be seen from the formula that the accuracy of setting a given value of K is determined by the error of setting m, which, in turn, is determined by the error of setting the attenuation coefficient K of the attenuator 2 operating in this device in the frequency band p. In the device there are no fundamental limitations on the |; frequency range 6 and the output signal can have values of tens and hundreds of megahertz, it is only necessary to ensure high-quality frequency conversion

live high enough conversion

Claims (1)

Invention Formula A complex signal generator calibrated by a harmonic coefficient, containing a sinusoidal signal generator connected to an attenuator, characterized in that, in order to improve the shaping accuracy, a phase modulator, first and second mixers, a reference oscillator, a controlled oscillator are introduced , an intermediate frequency filter, a low-pass filter and a phase detector, the output of the reference oscillator being connected to the first inputs of the first and 0 of the second mixer, and the second input of the second mixer is connected to the output of the controlled generator and the first input of the phase modulator, the output of the second mixer through the filter 5 intermediate frequency is connected to the first input of the phase detector, the second input of which is connected to the output of the sinusoidal signal generator and the input of the attenuator, the output 0 which is connected to the second input of the phase modulator, the output of the phase detector is connected to the input of the controlled oscillator, the output of the phase modulator is connected to the second input nepBOi o mixer, the output of which is connected to the input of the low-pass filter, the output of which is the output of the generator-calibrator.