SU794708A1 - Generator of radio pulses with frequency-modulated carrier frequency - Google Patents

Description

The invention relates to radio engineering and can be used to generate frequency modulated signals, for example, in radio transmitting devices.

, According to the main author. St. No. 642853 is known a radio pulse generator with a frequency-modulated carrier frequency, comprising a series-connected reference generator, a delay line, a frequency multiplier and a pulse amplifier, a series-connected pulse generator and an integrator, as well as a synchronizer, one output of which is connected to another input of the pulse amplifier and the other output To the input of the pulse generator, and in series between the output of the pulse generator and the control input of the delay line, a series-connected inverter and sum , The other input of which is connected to the output of the integrator 1.

However, the known device does not allow the formation of a nonlinear odd frequency modulation (FM) inside the radio pulse with increasing deviation of the carrier frequency.

The purpose of the invention is to form a nonlinear odd frequency modulation within a radio pulse with an increase in the carrier frequency deviation.

To do this, a radio pulse generator with a frequency-modulated carrier frequency, containing a series-connected reference generator, a delay line, a frequency multiplier and a pulse amplifier, a series-connected pulse generator and an integrator, as well as a synchronizer, one output of which is connected to another input of the pulse amplifier and the other the output is connected to the input of the pulse generator, and between the output of the pulse generator and the control input of the delay line are connected in series the inverter and the adder, each Its input is connected to the integrator output, the synchronizer is provided with a third output, and a harmonic oscillator is inserted between it and the third input of the adder.

FIG. Figure 1 shows the structural electrical circuit of the proposed device; in fig. 2 - voltage diagrams at various points; in fig. 3 - diagrams of phase and frequency changes.

The device comprises a reference oscillator /, a delay line 2, a frequency multiplier 5, a pulse amplifier 4, a pulse generator 5, an integrator 6, an inverter 7, an adder 8, a synchronizer 9 and a harmonic oscillator JO.

The proposed device operates as follows.

Harmonic oscillations from a highly stable source, such as a quartz reference oscillator 1, arrive at a controllable delay line 2, made in the form of a series of inductances, with electronically adjustable shunt diodes connected to the ground between them and the ground. These capacitive diodes through the integrating resistance receive a control pulse from the output of the voltage accumulator 8. Under the influence of the control voltage in the delay line 2, phase modulation is performed, resulting in the formation of frequency modulated oscillations.

Frequency-modulated oscillations arrive at frequency multiplier 3, where the carrier frequency and frequency deviation increase B integer number of times. Then, the pulse amplifier 4 provides gating radio pulses that enter the antenna and are emitted. The pulse amplifier 4 is started from the synchronizer 9. The amplifier 4 is connected to the first output of the synchronizer 9.

The formation of the control voltage at the output of the adder 8 is as follows.

The pulse generator 5 is connected to the second output of the synchronizer 9. A rectangular pulse produced by the generator 5 is fed to the integrator 6 and the inverter 7. The integration of the rectangular pulses creates a linearly varying voltage in the form of one pulse, for example, a circular polarity. At the output of inverter 7, there is a nr melago pulse, the polarity of which is negative, and the amplitude is equal to one half the amplitude of the linearly varying pulse. As a result of the summation of the voltages coming from the integrator 6 and the inverter 7, a bipolar linearly varying pulse is formed (Fig. 2a).

In contrast to the known device, in this case a harmonic oscillator (shock excitation) 10 is input, the output of which is connected to the adder 5 and the input is connected to the third output of the synchronizer 9. The generator 10 generates a harmonic oscillation, for example, of a sinusoidal form, whose period is equal to the duration of the emitted pulse , and the initial phase is phased so that at the beginning and at the end of the pulse the phase value is zero or a multiple of 2 (Fig. 26). At the output of the adder 8. the result of the summation of the sinusoid (Fig. 26) and the bipolar linearly varying voltage (Fig. 2 and) forms a nonlinear voltage in the extrinsic odd function (Fig. 2c). The voltage on the shunt diodes due to integration has the form of an even

functions, in this case in the form of a difference between a parabola and a cosinusoid (Fig. 2d).

- Under the influence of such a control pulse, the voltage across the bypass diodes due to the integration varies according to an even law that differs from a two-sided parabola. This, in turn, leads to the fact that the phase of the signal at the output of the delay line changes during a pulse also according to the law of an even function (Fig. 3a) to provides a non-linear two-sided, skew-symmetric frequency sweep (Fig. 3b).

To form a non-linear FM, a smaller phase change range is required than for a linear FM. This is an advantage of the invention. To form a linear FM with parameters F and T

Phase range DV is required,

proportional to the area, 8 81 + 82 (Fig. 36). In the proposed generator, in order to form a non-linear FM with the same parameters, a phase variation range proportional to the area Si is required. For the well-known nonlinear laws of the World Cup, Si "52. Consequently, in the proposed generator, to form FM radio pulses with the same base as in the known device, the range of phase change in the delay line is twice as small. Or, on the contrary, with the same line parameters, the FM radio pulses of the proposed generator have an increased frequency deviation and a signal base.

Thus, the proposed generator provides the formation of coherent radio pulses with non-linear frequency modulation, increases the efficiency of converting phase modulation to frequency modulation, improves the radar technical characteristics, reducing the signal-to-noise ratio by 1 dB, which is equivalent to an increase in transmitter power by 25% or range of action by 6%.

Claims (1)

Invention Formula The generator of radio-pulses with a frequency-modulated carrier frequency according to the author. St. No. 642853, characterized in that, in order to form a nonlinear odd frequency modulation inside the radio pulse with increasing deviation of the carrier frequency, the synchronizer is provided with a third output, and a harmonic oscillator is inserted between it and the third input of the adder. The source of information taken into account in the examination: I. USSR Copyright Certificate No. 642853, cl. H 03 K 3/80, 1976 (prototy). u -and + y about / l .z W (t Sho A