SU1054870A1 - Serrodyne converter - Google Patents

Description

The invention relates to radio engineering and can be used to obtain a single sideband signal in various radio systems. A serrodin converter is used, containing a traveling wave tube (TWT) and a sawtooth source, including two sawtooth voltage generators, a phase inversion cascade, and a generator of control alternating rectangular impulses of equal duration ,. The output of the pivot voltage source is connected to the retarding TWT system and performs periodic modulation of the accelerating voltage of the LEV by the saw-like law. However, such a serrodin converter has a high level of spurious amplitude modulation of the output signal when the frequency of the input signal changes in the TWT frequency range. The closest to the proposed is a serrodynamic transducer containing a series-connected controlled attenuator and a traveling will lamp; e, to the control input of which a saw-head voltage source is connected, as well as a directional coupler and an envelope detector, with the tensioner being connected at the entrance of the TWT, and the output of its secondary line, is connected to the control input of the TWT via successively connected phase shifters with a 90 envelope detector and a control device G2. However, this serrodinic. Transmitter has a relatively large parasitic amplitude modulation of the output signal with a change in the frequency of the input signal. The purpose of the invention is to reduce the parasitic amplitude modulation of the output signal. This goal is achieved by the fact that in a serrodin converter containing a series-connected controlled attenuator and - ,. the 6th wave wave tube, to the control input of which the sawtooth source is connected, as well as the directional coupler and the envelope detector, between the output of the envelope detector and the control input of the controlled attenuator, are connected in series with a band-pass filter, a rectifier and. the adjustable inverting amplitude of the control input of which is connected to the output of the sawtooth source, the input of the directional response connected to the output, TWT, and the output of the secondary line of the directional coupler to the input of the envelope detector. Fig. 1 shows the structures on the electric circuit of the seminal-voltage converter in Fig. 2; time diagrams of its operation. The serrodin converter contains an adjustable inverting amplifier 1, a controlled attenuator 2, a TWT 3, a directional coupler 4, a rectifier 5, a sawtooth source 6, an envelope detector 7 band filter 8, Serrodinny Converter works as follows. The converted microwave signal is fed through the controlled attenuator 2 to the signal input of TWT 3, to the control input (slowdown system) of which a sawtooth voltage of a fixed frequency is applied from source b (Fig. 25J. The frequency of this voltage is equal to the required frequency shift of the output microwave -signal serrodin converter with respect to the input Under the influence of a periodic sawtooth, the external microwave signal TWT 3 is shifted in frequency relative to the input by an amount equal to the frequency of the sawtooth source b oscillations. The main part of the output of the TWT 3 microwave signal is output to the serrodin converter (FIG. 2 a /, and part of the microwave signal from the TWT 3 output, from the output of the secondary line of the directional coupler 4 enters the input of the envelope detector 7, the Envelope Detector 7 extracts the amplitude modulation envelope (FIG. 2 b), the band-pass filter 8, tuned to the sawtooth oscillator source b, and extracts from the entire envelope spectrum the amplitude modulation coming from the envelope detector 7 only the first harmonic of the envelope (FIG. 2 into | which enters the input of the rectifier 5. The periodic sawtooth voltage of the source b is fed in antiphase through an inverting adjustable amplifier to the control, the input of the controlled attenuator 2 The signal from the output of the bandpass filter 8 is rectified by the rectifier 5 (Fig 2 g) Thus, at the output of the rectifier 5, a constant signal always takes place, the level of which is proportional to the level of parasitic modulation of the output signal of the serodinic converter. The signal from the output of the rectifier 5 is fed to the control input of the regulator inverter amplifier 1 and changes the amplitude of the sawtooth voltage supplied to the control input of the controlled attenuator 2 (Fig. 2 e), according to the law of the envelope of parasitic amplitude modulation. The output signal of the controlled attenuator 2 (FIG. 2 g) changes the power of the microwave signal at the TWT 3 input as follows; if the signal power at the output of the LEV 3 is increased, then the controlled attenuator 2 reduces the microwave input power of the LEV 3 as a result of which the output power; de LEV 3 decreases; if the power of the microwave signal at the output of the TWT 3 decreases, then the controlled attenuator 2 starts the input microwave frequency of the TWT 3, as a result of which the power at the input of the TWT 3 increases.

Thus, in the proposed device, after the time of setting iy (Fig. 2), the depth of the parasitic amplitude modulation is reduced, and the unwanted harmonics determined by it are suppressed.

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Claims (1)

SERRODYN CONVERTER,. comprising a serially connected controlled attenuator and a traveling wave lamp (LBV), to the control "input of which a sawtooth voltage source is connected, as well as a directional coupler and an envelope detector, characterized in that, in order to reduce spurious amplitude modulation of the output signal, between the detector output the envelope and the control input of the controlled attenuator are connected in series with a bandpass filter, a rectifier and an adjustable inverting amplifier, the control input of which is connected is connected to the output of a sawtooth voltage source, while the input of the directional coupler is connected to the TWT output, and the output of the secondary line of the directional coupler is connected to the input of the envelope detector. SU, 1054870