RU-1841401-C - Device for optimizing the spectrum of a frequency-shifted signal

Abstract

FIELD: radio countermeasures. SUBSTANCE: invention relates to the field of radio countermeasures and is intended for use in a retransmission-type active jamming station for suppressing the continuous-wave radar speed channel. The claimed device for optimizing the spectrum of a frequency-shifted signal contains a traveling-wave tube phase shifter, whose input and output are connected to the first and second inputs of a balanced mixer, respectively, and a sawtooth voltage generator, whose output is connected to the control input of the phase shifter. Between the output of the balanced mixer and the input of the sawtooth voltage generator, there are a limiter amplifier, a pulse shaper, a pulse counter, and a trigger with a counting input connected in series. EFFECT: technical result is to expand the frequency range of the modulating voltage while maintaining a wide operating frequency range for the input high-frequency signal. 1 cl, 2 dwg

Inventors

• Antyukhin Mikhail Akimovich
• SOLODCHENKO ANATOLIJ MIKHAJLOVICH

Assignees

• Акционерное общество "Центральный научно-исследовательский радиотехнический институт имени академика А.И. Берга"

Dates

Publication Date

20260506

Application Date

19770606

Claims (1)

1. A device for optimizing the spectrum of a frequency-shifted signal, comprising a phase shifter on a traveling wave tube, the input and output of which are connected respectively to the first and second inputs of a balanced mixer, and a sawtooth voltage generator, the output of which is connected to the control input of the phase shifter, characterized in that, for the purpose of expanding the range of operating frequencies, an amplifier-limiter, a pulse former, a pulse counter and a trigger with a counting input are introduced in series between the output of the balanced mixer and the input of the sawtooth voltage generator.

Description

The invention relates to the field of radio countermeasures and is intended for use in a repeater-type active jamming station for suppressing the speed channel of a continuous-wave radar. A device for optimizing the spectrum of a frequency-transferred signal is known (see "Explanatory Note to the Technical Project "Geran-1UD", Moscow, 1971 [L1]), consisting of an electronic phase shifter on a TWT, the control input of which is connected to a sawtooth oscillator through an amplifier-modulator. Moreover, the gain of the latter is discretely changed in response to commands coming from a frequency meter connected to the TWT input. As a result, a rough compensation for the change in the phase sensitivity of the TWT in the operating frequency range is performed. A disadvantage of the analog is the low quality of optimization of the spectrum of the transferred signal, since information about the output spectrum is not used in controlling the amplitude of the sawtooth oscillations. The closest in technical essence is the "Device for Optimizing the Spectrum of a Frequency-Shifted Signal." It contains an electronic phase shifter based on a TWT, the high-frequency input and output of which are connected to the inputs of a balanced mixer, and the control electrode of the phase shifter is connected to a sawtooth generator, the amplitude of which is controlled by an automatic tuning circuit connected between the output of the balanced mixer and the sawtooth generator. The input and output of the phase shifter are the input and output of the prototype device. The prototype works as follows. The input signal is "blended" in a balanced mixer with the phase-modulated output signal of the TWT, shifting the latter's spectrum to the low-frequency region. Analyzing filters tuned to the frequencies of the first and second harmonics of the modulating voltage are connected to the mixer output. The signals extracted by the filters are detected, summed (with a specific amplitude ratio), and, after amplification, fed to a sawtooth generator, adjusting its amplitude. Feedback maintains the spectral components of the phase-modulated signal constant over a wide range of the high-frequency signal's operating frequencies. A significant drawback of the prototype is its inability to operate under conditions where the modulating voltage frequency varies widely (for example, when implementing speed-dependent interference, the frequency tuning factor of the sawtooth generator reaches 300 or more [L1]). A second drawback of the prototype is the fixed phase deviation value at which the device operates normally. The proposed device has as its main goal the expansion of the frequency range of the modulating voltage while maintaining a wide range of operating frequencies of the input high-frequency signal. This goal is achieved by incorporating a series-connected amplifier-limiter, pulse shaper, controlled pulse counter, and counting trigger into a frequency-shifted signal spectrum optimization device consisting of an electronic phase shifter, the input and output of which are connected to the inputs of a balanced mixer, and a control electrode connected to a sawtooth generator. The input of the amplifier-limiter is connected to the output of the balanced mixer, and the output of the trigger is connected to the input of the discharge device of the tunable sawtooth generator. The block diagram of the proposed device is shown in Fig. 1. The device contains the following connected in series: - electronic phase shifter 1, made on TWT; - tunable sawtooth oscillator 2; - balanced mixer 3; - amplifier-limiter 4; - pulse generator 5; - controlled pulse counter 6; - trigger 7, operating in the counting start mode. The device works as follows. The input signal with frequency ω o , arriving at the phase shifter, is phase-modulated by a sawtooth voltage (Fig. 2a). As a result of this operation, the output signal of the phase shifter will be shifted [L2] in frequency by the value Δω, that is, the frequency of the output signal ω will be equal to: ω 1 =ω o +Δω When the input (ω o ) and output (ω 1 ) signals of the phase shifter are fed to the balanced mixer, the output of the latter produces a voltage U BS (t), determined by the expression: U BS (t)=U o cosΔω⋅t (1), where U o is the voltage amplitude at the output of the balanced mixer. The voltage U BS (t) obtained at the output of the balanced mixer (Fig. 2b) is fed through an amplifier-limiter to the pulse former, from the output of which short pulses are taken (Fig. 2c), corresponding to the moments of intersection of the sinusoidal voltage with zero potential. From a comparison of Figs. 2b and 2c it is evident that the output pulses of the former appear every half-period of U BS (t), that is, when the phase of the modulated signal changes by π rad . Then the pulses from the former are fed to the controlled counter, the required conversion factor K sc [L3] of which is set by the signal U control2 . With the a