SU579682A1 - Frequency synthesizer - Google Patents

Description

(54) FREQUENCY SYNTHESIZER

The invention relates to radio engineering.

A frequency synthesizer is known, containing a series-connected reference oscillator, a phase detector, a lower filter, a synchronized oscillator, their frequencies, and a bandwidth filter, and a dimmer afterwards.

torus frequency stand and frequency modulator, the output of which is connected to another input of the mixer; In this case, between the other output of the synchronized generator and the other input of the phase detector, a frequency divider with a variable division factor ij is turned on.

However, the known frequency synthesizer has a long time for setting the output oscillation parameters.

The purpose of the invention is to reduce the time of setting the parameters of the output oscillation.

For this purpose, a frequency synthesizer containing a series-connected reference g: Ch1orator, a phaeo detector, a low-pass filter, a synchronized generator, a mixer and a band-pass filter, as well as series-connected stand frequency generator and a frequency modulator, the output of which is connected to another mixer input between the other output of the synchronized oscillator and the other input of the phase detector, a frequency divider with a variable division factor is switched on, between the other output of the low-pass filter and the distortion It introduced an AC amplifier at the input of a frequency modulator.

The drawing shows a structural electrical circuit of the device.

The frequency synthesizer contains a series-connected reference generator 1, a phase detector 2, a low-pass filter 3, a synchronized generator 4, a mixer 5 and a band-pass filter 6, as well as series-connected frequency generator of the stand 7 and frequency modulator 8, the output of which is connected to another mixer input 5. Between the other output of the synchronized generator 4 and the other input of the phase detector 2, the non-nitol is switched on

Claims (1)

frequency 9 with variable) ha1H 1H1X) m healing; An alternating current amplifier Y is inserted between the alternate output of the low-pass filter 3 and the control input of the frequency amplifier. The device operates as follows. In a static mode, the output of the low-pass filter .3 maintains an approximately constant level of control voltage, which provides a fundamental level automatic frequency control (PLL), the frequency of the co-fing of the synchronized generator 4 is necessary in accordance with the division factor. This signal, due to its constant level and the presence of an AC amplifier 10, is not present at the input of the frequency modulator 8. In this case, the frequency modulator 8 is synchronized only by means of capturing the frequency of the frequency generator of the stand 7. In this case, the frequency modulator .8 One of the inputs of the mixer 5 receives a signal whose parameters are determined by | Parameters of the signal of the frequency generator of the stand 7. In dynamic mode, i.e. when switching to a new operating frequency by changing the division factor of the frequency divider with a time division factor of 9, a transition process begins in the digital PLL of the synchronized oscillator 4, which is oscillatory with the inertial lowpass filter 3. The nature of the change in the frequency of the synchronized oscillator 4 in a dynamic mode is unambiguously characterized by the type of control signal at the output of the low-pass filter 3. As in the dynamic mode, the component of the output signal of the AC amplifier 10 is large, then the effect of this signal on the frequency-generating elements of the circuit of the frequency modulator 8 is dominant in comparison with the synchronizing effect of the signal of the frequency generator of the stand 7, which prevents any change in the frequency of the signal at the output of the frequency MO of the controller 8. By changing the component of the control signal from the AC amplifier 10 to the control input of the frequency modulator 8 The frequency of the signal at the output of the frequency modulator is changed according to the law of the variable signal of the control signal. But the type of control signal at the output of the AC amplifier 10 is unambiguously related to the nature of the change in the frequency of the synchronized generator 4 in the divamic mode. From this it follows that the changes in the frequency of the output signal of the frequency modulator 8 and the synchronized generator 4 are uniquely connected. So, at the difference intermediate frequency f p, at the output of the mixer 5, the alternating current amplifier Yu must provide the minimum phase shifts for the control signal in order to provide a single-characteristic and equal frequency measurement. generator frequency stand 7 at the output of the frequency modulator 8 and frequency i. the signal of the synchronized generator 4 in the dynamic mode. Thanks to this, the time of setting the parameters of the working signal is significantly reduced. Thus, the described device provides a reduction in the time of setting the parameters of the output oscillation and nt improves the speed of the frequency synthesizer. The invention includes a frequency synthesizer comprising a series-connected reference oscillator, a phase detector, a low-pass filter, a synchronized oscillator, a mixer and a band-pass filter, as well as serially connected stand frequency generator and frequency modulator, the output of which is connected to another mixer input, between another output synchronized generator and other input phase retector included. a frequency divider with a variable division factor, characterized in that, in order to reduce the setting time of the output oscillation parameters, an AC amplifier is inserted between the other output of the Lower Frequency filter and the control input of the frequency modulator. Sources of information taken into account in the examination: 1. Levin V. A, Stabilization of a discrete set of frequencies. M., Energy Publishing House, 1970, p. 12 122.124.