SU1317643A2 - Frequency-modulated crystal oscillator - Google Patents

Abstract

The invention relates to radio engineering. In relation to auth. No. 1084945 provides the purpose of the invention to reduce the distortion of the modulation law. The device contains a source of 1 modulating signal, filters 2 and 6 of the lower and upper frequencies of a block of notch filters 3, frequency and phase modulators 4 and 8, quartz g-r 5, integrator 7 and delay line (LZ) 9. Goal Achieved the introduction of LZ 9, with which the beginning of the action of instantaneous frequency deviations from the outputs of the frequency and phase modulators 4 and 8 coincides in time. Given il. possible cases of inclusion of LZ 9 in the device. 2 Il. f) ns & b 4 00 Q3U2.1

Description

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The invention relates to a radioteznik and can be used to generate frequency-modulated oscillations in transmitting devices of communication systems, telemetry, and radiolocation.

The purpose of the invention is to reduce the distortion of the modulation law.

FIG. Figure 1 shows the structural electrical diagrams of the proposed frequency modulating () crystal oscillator, possible cases of switching on the delay line; in fig. 2 - timing diagram of the generator.

A frequency-modulated crystal oscillator contains a source of a modulating signal, a low-pass filter 2 (LPF), a block of 3 notch filters, a frequency modulator 4, a quartz oscillator 5, a high-pass filter 6 (PFC), an integrator 7, a phase modulator 8 and a line 9 delays.

The frequency modulated crystal oscillator (Fig. 1a) operates as follows (I, Fig. 2).

When applying to the input of the lowpass filter 2 a pulsed: modulating signal (Fig. 2a) from the source 1 of the modulating signal, part of the spectrum of this signal through the LPF 2 (Fig. 26) is fed to the input of block 3 of the notch filters, where it is delayed by time T, equal to the slope (phase-frequency characteristic of the selected filter (FIG. 2c) and is fed to the input of frequency modulator 4), as a result, the oscillation frequency of the crystal oscillator 5 changes according to the law of the modulating signal taken from the output of the low-pass filter (Fig. 2g) passing through the block 3 delay Tj. With Supplying a part of the spectrum of the modulating signal through the delay line 9 (Fig. 2d) of the low-pass filter 6 (Fig. 2e) and the integrator 7 (Fig. 2e) to the input of the phase modulator 8 is the phase of the signal removed from the output of the phase modulator 8 (Fig. 2.1. e), changes according to the law of the output from the HPF 6, taking into account the integrator 7 and the delay line 9, and the oscillation frequency according to the law derived from the law of change of the signal from the output of the HPF 6, taking into account the integrator 7 and the delay line 9 (Fig. 2h).

Due to the effect of the introduced delay line 9, the onset of instantaneous frequency deviations from the outputs of frequency modulator 4 and phase

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modulator 8 coincides in time. As a result of vibrations from the lowpass filter 2 outputs with a block of 3 notch filters and highpass filters with an integrator 7 and

the delay line 9, respectively, to the frequency modulator 4 and phase modulator 8, the oscillation frequency at the output of the quartz-FM oscillator (Fig. 2i) varies according to the law of the source of the modulating signal 1 taking into account the constant delay due to the constant time of the delay line 9 easy to consider on the receiving side when processing the received information.

Line 9 of the delay can be connected between the output of the HPF 6 and the input of the integrator 7 (Fig. 16) or between the output of the integrator 7 and the input of the phase modulator 8 (Fig. 1c). Wherein

a quartz-FM generator operates in a manner similar to that shown in FIG. 1a

Timing diagrams of the signals when turning on the delay line 9 in accordance with FIG. 16 and 1c are shown respectively in FIG. 2.II and 2III; a is the signal at the output of the source 1 of the modulating signal; b - signal at the output of low-pass filter 2; c - output signal

block 3; g - signal at the output of the delay line 9; d - at the output of the highpass filter 6; e is the signal at the output of the integrator 7; W - signal at the output of the crystal oscillator 5; 3 - signal at the output of the phase modulator 8; and - the output signal of the quartz-FM generator.

To ensure that the frequency deviation is constant for the duration of the rectangular modulating signal by selecting the mode of the frequency modulator 4, the frequency of the signal ID is outputted on the output of the quartz oscillator 5f equal to the frequency deviation c

the output of the phase modulator 8, as well as the selection of the delay T, the signal in the delay line 9, equal to the delay of the signal T, in the channel of the crystal oscillator 5. From the output of the quartz

The FM generator is taken out of the FM signal with the law of frequency change corresponding to the shape of the signals of the source of the modulating signal 1. This is also true when transmitting harmonic modulating signals, as a result, the frequency modulation characteristic is uniform - depending on the frequency deviation of the modulating harmonic signal

31317643 4

constant amplitude of each frequency, which, with a modulating spectrum. To reduce the distortion of the modulation law, the source of the modulating signal is connected to the input of the upper filter. Frequency modulated quartz frequency 5 through the input delayed-oscillator line by auth.St. № 108А945, о тки.

Claims (1)

Invention Formula Compiled by G. Zakharchenko Editor L. Pchelinska Tehred M. Khodanych Proofreader A. Ilyin Order 2434/54 Circulation 901 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-355, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Well CDUt.l