SU1532990A1 - Frequency synthesizer - Google Patents

Abstract

This invention relates to a frequency synthesis technique. The purpose of the invention is to increase the speed by reducing the duration of transients when tuning from frequency to frequency. In the synthesizer, the signal from the reference g-1 is fed to the signal input of the controlled phase-shifter 3 directly, and to the control input via the circuit consisting of serially connected blocks 2 of the reference frequency, forming 4 pulses, g-5 sawtooth voltage, differential amplifier 6, switch 7 and amplifier 8 with an adjustable gain factor. This circuit generates a control signal that determines the magnitude and sign of the frequency tuning of the synthesizer with respect to the frequency of r-1. When it arrives at the control input of the phase shifter 3, this signal shifts the frequency of r-1 by a predetermined value. 2 Il.

Description

(Ls

The invention relates to a technique of frequency synthesis and can be used to create transceiver radio engineering complexes.

The purpose of the invention is to increase the speed by reducing the duration of transients when tuning from frequency to frequency.

FIG. 1 and FIG. 2 (a-e) respectively, a structural electrical circuit of the frequency synthesizer and timing diagrams of its operation are presented.

The frequency synthesizer contains a reference oscillator 1, a reference frequency block 2, a controlled phase shifter 3, a pulse shaper 4, a pi voltage generator 5, a differential amplifier 6, a switch 7, and an adjustable gain amplifier 8.

The frequency synthesizer works as follows about

Reference generator 1 generates a signal with frequency o) & . To produce at the output of a frequency synthesizer a signal with

 ir21Ti dF,

where LF is the frequency grid step, i Oj il; ± 2 $ ..., irn, serves as a controlled phase shifter 3. With a linear change in the phase of the signal with frequency s0 in the controlled phase | 3x clock maker over time

T t change the frequency of the output Lg

the signal of the controlled phase shifter 3 will be

27m Fi LR.

Thus, the formation of the required frequency grid with LR pitch is carried out.

The modulation frequency 3F (FIG. 2a) is formed in reference frequency block 2 from frequency 0) 0 of reference oscillator 1.

In the pulse shaper 4, a sequence of short pulses is formed from the sinusoidal signal of the reference frequency block 2 (FIG. 26), which starts the generator 5. The sawtooth with a period T is fed to the input of the differential amplifier 6, at two outputs of which two sequences of sawtooth pulses

0

-

five

five

0

five

-

amplitudes: direct - with increasing voltage (Fig. 2c) and inverse - with decreasing voltage (Fig. 2d). Using the increasing voltage on the control input of the controlled phase shifter 3 causes the input frequency tJ0 to shift to + 2JTidF, using a decreasing voltage leads to a shift on. Both sequences are fed to the first and second inputs of the switch 7, and the code control signal also goes to the control input of the switch 7, which determines the sign of the output frequency shift relative to.

The selected pulse sequence from the output of the switch 7 is fed to the amplifier 8 with an adjustable gain factor. The amplitude of the sawtooth voltage at the output of the amplifier 8 with adjustable gain determines the magnitude of the output frequency shift relative to j30. The gain control is controlled by the remaining bits of the code control frequency signal.

Thus, at the output of the amplifier 8 with an adjustable gain factor, a control signal is formed (Fig. 2e), which determines the magnitude and sign of the frequency tuning of the synthesizer relative to the frequency tvc. The input to the control input of the controlled phase shifter 3, the control signal, produces a frequency shift 0 by a value of ± 2ffi / jF.

In the frequency synthesizer, the increase in speed is determined by a decrease in the switching time of the switch 7 and the amplifier 8 with an adjustable gain factor, which is a few nanoseconds, due to their wideband network.

In the frequency synthesizer, the switching time from frequency to frequency decreases by a factor of 101 to 105, the limit value of the output frequency increases, and the reference frequency block is simplified.

Claims (1)

Invention Formula A frequency synthesizer containing a reference oscillator, the output of which is connected to the input of the reference frequency unit and the input of the controlled phase shifter, characterized in that that, in order to increase speed by reducing the duration of transients during the restructuring from frequency to frequency, introduced after-. force-connected pulse shaper, sawtooth generator and differential amplifier, as well as a series-connected switch and amplifier with adjustable gain, the output of which is connected to the control input of the controlled phase shifter, while the output of the reference clock ten The currents are connected to the input of the pulse generator, the first and second outputs of the differential amplifier are connected respectively to the first and second inputs of the switch, the control input of which is connected to the control input of the amplifier with adjustable gain and the input of the control code signal, and the output of the controlled phase shifter is a frequency synthesizer output.  I I I I I Lll /  NNNNNN but / Fm.g