SU680186A1 - Retranslator of frequency-modulated oscillations - Google Patents

Description

The invention relates to radio engineering. A repeater of frequency-modulated oscillations is known, comprising input and terminal amplifiers, a local oscillator, a correction circuit and a series-connected mixer, an intermediate frequency amplifier and a limiter l. However, the well-known repeater of often non-modulated oscillations has insufficient noise immunity. The purpose of the invention is to increase the stability of the device. To do this, a phase modulator, a series-connected mixer, an intermediate frequency amplifier and a limiter, phase modulator, frequency transfer unit, series-connected phase detector, filter, and phase shifter are inputted into the repeater of frequency-modulated oscillations, containing the input and terminal amplifiers, a local oscillator, and the input amplifier is connected through a series-connected phase modulator and a final amplifier to one input of the mixer, the other input of which is connected to the output of the input An amplifier through a frequency transfer unit, another input of which is 90 connected to the first output of the local oscillator, and its second output to another input of the phase shifter, while the output of the limiter is a series-connected phase detector and a correction circuit connected to another input of the phase modulator. The drawing shows a structural electrical circuit of the proposed device. Frequency modulated oscillator repeater contains input amplifier 1 | terminal amplifier 2, phase modulator 3, frequency transfer unit 4, mixer 5, intermediate frequency amplifier 6, limiter 7, phase detector 8, phase shifter 9, LO 1O, correction circuit 11 ifnlrt 12. The device works as follows. The signal arriving at the input of the transponder is amplified by the input amplifier 1 and fed to the final amplifier 2. A part of the power of the retransmitted signal goes to the frequency transfer unit 4, in which the spectrum is transferred, the signal (frequency shift) by a fixed value of ±. - determined by the frequency of heterodyne 10. The signal shifted in frequency is fed to one of the inputs of the mixer 5, and to the other its input receives part of the signal power from the output of terminal amplifier 2. In linear mode, away from the saturation region of the signal distortion in the final amplifier 2 are minor. If the final amplifier 2 operates at the saturation region, the parasitic amplitude modulation present in the retransmitted signal is converted into phase modulation which distorts the signal, as a result of which the output signal of the mixer 5, like the signal of the amplifier 6, the intermediate frequency is modulated in phase, with the parasitic phase modulation of these signals corresponding to that created in the distorting stage of the repeater. The input signal from the output of the amplifier 6 together with the oscillation of the local oscillator 10 to the phase detector 8, we obtain at its output a selected modulating oscillation. After amplification and correction, this oscillation goes in antiphase to the modulation input of phase modulator 3, creating a phase change opposite to that occurring in terminal amplifier 2. Since the initial phase of the intermediate frequency signal depends on the carrier frequency of the input signal, it is necessary to adjust the heterodyne phase oscillations supplied to the phase detector 8. This adjustment is performed by the phase shifter 9, the control signal for this phase shifter is produced at the output of the phase detector 8. Components the oscillating oscillations emitted by the phase detector 8 are suppressed by the filter 12

and at the input of the phase shifter 9 is not received.

To determine the degree of decrease in the depth of spurious modulation in a device, the input signal is represented as

) (J (- (- ii5inSl.f) COsCuJoi: - Ct)

the output of the phase detector 8 does not depend on the frequency Wti

); (fe)

Claims (1)

where k const de m is the parasitic amplitude modulation coefficient at the frequency SI; UUQ-carrier frequency signal; US) - modulation is useful. Since the input amplifier 1 operates in the linear mode and does not introduce any noticeable distortion, then the output signal of the phase modulator 3 is of the form 2 Up 5 L С05Сш) Л, С2) de Lfg (t) - component modulation, insertable phase modulator 3. Termination amplifier 2 generates additional parasitic phase modulation (t). In the lakeshe of the traveling wave of the final amplifier 2, there is also a signal support for some time tT from C-b) - (- m sidSi-t cosCuUot-t (tT) Ct-C) (t), (3) where Kn is the new value of the amplitude coefficient modulation. Using dependencies of dependencies (1) to (3), and also taking into account the frequency shift in the frequency transfer unit 4, we obtain the expression for the intermediate frequency signal about O msmSl-iyHUnp nfj-cos () -M (.t-tr) -4gtt-C -) - uu t-yCt) :. Since f is small, VCt 2: 4Ct - C), 4TjC-b) (t-t). and the output voltage of the phase detector 8 (after limiter 7) J4 -Vp o8 ct- 6 ot: -Tttn. From expression (5), it is obvious that the initial phase of the voltage 1/4 (i) depends on the carrier frequency U) o. The voltage on Denote the transfer function after the detector circuit (amplifier 1 with a correction circuit 11) across K (p), taking into account dependencies of pairs (1) (2) the equation for determining fg is aJot-HC-tVKCpVkC t :) X, ( JUo-t44 (t)),., ,,, kK (pVjr (t) /. Ch. () RZT T TTT, (V 1-ПГкТрТ and with) U) C: - 3r (t). Thus, with a sufficiently large amplification of the feedback circuit, the overall phase change in the path of the repeater is close to zero. The technical and economic efficiency of frequency modulated oscillation retransmitting is a higher noise immunity. Claims of the invention Repeater of frequency-modulated oscillations, containing input and terminal amplifiers, heterodyne, a correction circuit and a series-connected mixer, an intermediate-frequency amplifier and a limiter, so that, in order to increase noise immunity, A phase modulator, a frequency transfer unit, a phase detector connected in series, a filter and a phase rotator are introduced, the output of the input amplifier connected via a serially connected phase modulator and a terminal amplifier It is connected to one input of the mixer, the other input of which is connected to the output of the input amplifier through a frequency transfer unit, another input which is connected to the first output of the local oscillator, and its second output to another input of the phase shifter, and the output of the limiter through the series-connected phase detector and The correction circuit is connected to another input of the phase modulator. Sources of information taken into account in the examination of 1, A. Vinnishy. Modulated filters and the following method of the World Cup, M., Sov. radio, 1969, p. 146.