SU1434534A2 - Shaper of frequency-modulated oscillations - Google Patents

Abstract

Image bridging refers to radio engineering. The purpose of the invention is to reduce distortion of the modulation law. The device contains a source of 1 modulating signals, a low frequency component (LPF) 2, controlled by frequency, quartz g-3, made in the form of quartz g- pa 9 on a transistor with a quartz peso-i converter in the base circuit and frequency modulator (FM) 10 on the varicap, high-pass filter 4, phase inverter 5, phase modulator 6. To achieve the goal, a band-pass filter is introduced into the device (PF ) 7 and attenuator 8. PF 7 m. performed on the operational amplifier with the highest possible quality and that the phase of the signal passing through the FS 7 is unchanged. Attenuator 8 m. B, made on the elements of discrete technology or resistors. As a result of the joint action of oscillations from the outputs of the low-pass filter 2 and attenuator 8 to the input of the FM 10 and from the output of the filter 4 from the phase inverter 5 to the input of the phase modulator 6, the oscillation frequency at the output of the device changes according to the law specified by the source 1 signal. 1 il. 5s

Description

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Output

The invention relates to radio engineering and can be used to generate frequency-modulated oscillations in transmitters of a communication system, telemetry, and radar. The purpose of the invention is to reduce the claims of the modulation law.

The drawing shows a structural electric circuit of the proposed fo: 5 ffloflater frequency-modulated oscillations.

The shaper of frequency-modulated oscillations contains a source of 1 modulating signals, a filter 2 of the lower frequencies: one (LPF), a frequency crystal control (UKG) 3, a high-frequency filter 4 (HPF), a phase inverter 5, a phase modulator 6, band-pass filter (PF) 7 and attenuator 8.

A frequency-controlled crystal oscillator 3 can be made in the form of a crystal oscillator 9 on a transistor with a crystal oscillator in the value of the base and frequency modulator 10 on the I varicap (variable capacitance), turn on the Vb series resonator with the quartz-Bbnij resonator, and the output signal LPF 2 enters the input varicap |

| phase modulator 6 can be a high-frequency amplifier on the I transistor, tuned to the frequency i of the quartz oscillator, the capacitance of the resonant circuit of which contains a varicap, the input of which comes from the output. High pass filter 4 through phase inverter 5.

1FHF 2 and HPF 4 can be performed on IX-elements, with the signal from the capacitor of the KS circuit in the LPF 2 and from the Resistance - in the HPF 4.

PF 7 can be performed on an operational amplifier with the greatest possible quality, at which the phase of the signal passing through PF 7 is unchanged. Attenuator 8 can be performed on elements of discrete technology or on resistors.

Phase inverter 5 can be performed on the elements of discrete technology, or in the form of an analog amplifier with a transmission coefficient equal to K ° 1 ..

The shaper of frequency-modulated oscillations is as follows

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in a way.

When applying to the input of the low-pass filter 2 pulsed modulating signal from the source 1 of the modulating signal part

the spectrum of this signal is through the low-pass filter 2, folded with the signal taken from the output of the attenuator. 8, is fed to the input of the frequency modulator 10, as a result of which the oscillation frequency of the quartz oscillator 9 changes according to the law of sum-modulating signals from the output of the low-pass filter 2 and attenuator 8.

When a part of the spectrum of the modulating signal is fed through the HPF 4 and the phase inverter 5 to the input, the phase modulator 6, the phase of the signal taken from the output of the modulator 6 changes according to the signal from the output of the phase inverter 5, and the oscillation frequency is derived from the law of change of the signal from the phase inverter output 5.

At the same time, the inverted part of the spectrum of the modulating signal, coinciding with the frequency of the PF 7 tuning, from the phase-output 5 output, through the attenuator 8 enters the input of the frequency modulator 10, where it is summed with the non-certified part of the modulating signal passing through the LPF 2. As a result, the level modulating signal for those frequencies that coincide with the frequency of tuning the FS 7, tends to zero, since at these frequencies the signal from the output of FYCH 2 and the signal from the output of Attenuator 8 is opposite to phase, therefore, the level of the module of the signal applied to the frequency modulator 10 tends to zero, and the frequency deviation at the output of the crystal oscillator 9 also tends to zero,. I

As a result of the combined effect of the oscillations from the outputs of the low-pass filter 2 and the attenuator 8 pa the input of the frequency modulator 10 and the output of the high-pass filter 4 with the phase inverter 5 to the input of the phase modulator 6, the oscillation frequency at the output of the frequency-modulated oscillator is changed by the signal source 1,

PF 7 and attenuator 8 significantly reduce the parasitic change in the devia frequency due to the side resonance of the crystal oscillator 9 due to the fact that the frequency generator 7 is tuned to a frequency that coincides with the frequency of the side response onance of the crystal oscillator 9, and the coefficient of transmission of the attenuator 8 is matched to the maximum suppressing this frequency at the input of the frequency modulator 10, i.e. of equality

31434534.

Claims (1)

the levels of this frequency from the output of the lowpass filter 2 of the invention and the attenuator 8. If there are several side-timers of the frequency-modulated resonances of the quartz resonator of un-, oscillations using autor.St.N. 959258, It is necessary to supply an appropriate distinction in that the number of band-pass filters and the purpose of reducing the distortion of the law of tenuators, each of the band-pass filter modulations, between the output of the phase inverters must be tuned to the frequency generator and the input controlled by the frequency modulation coinciding with the frequency Q those of the quartz oscillator are inserted side-by-side resonances of the quartz resonator United Band nanator.filter and attenuator.