SU758530A1 - Device for automatic tuning of microwave generator frequency - Google Patents

Description

A common modulator 5, a mixer b and a separation element 7, a lower filter 8 (LPF), a phase detector 9, an additional mixer 10 and a second intermediate frequency amplifier 11 (IF), as well as two isolating elements 12, 13 and microwave output 14 signal.

The device works as follows.

The signal of the tunable microwave generator 1 through the initiation of elements 12 and 13 is fed to the mixer b and the tamplitude modulator 5 from one side. Due to the presence of the noise spectrum in the first IFA 4 tuned to the frequencies L, they cause amplitude modulation of the microwave signal in the amplitude modulator 5.

If the reference resonator 3 is tuned in such a way that

(one)

fp.

where fp is the resonant frequency of the reference resonator 3;

L frequency passing through the first IFC 4 signal; f is the frequency of the tunable microwave generator 1 signal, then the signal generated at modulation with frequency fc

goes through

the reference resonator 3 enters the mixer b, where as a result of mixing it with the fow signal, the I signal is released. When amplified in the first IFC – 1, it enters the amplitude modulator 5 again, resulting in a fp signal of larger amplitude and so on. Therefore, if a balance of amplitudes and phases is observed, system 2 will excite itself. .

Phase ratios of the system 2 F. CR, 4 MB

f + -O P

 N5

3b -% - fpA P

View: P45-% 4-V

About p

() Whose 15 -I

5 here are tp and cjj. - Phase-frequency characteristics of the reference re- torulator: onator 3 and first IFA 4, respectively; l fp and cft - fluctuations in the frequency of signals passing through this resonator 3 and first IFA 4 at fluctuations of frequency Af and tunable microwave generator 1. shift phases in the corresponding elements, with the first index showing which element the signal is coming from, and the second index where it comes from (arrives.

Solution of the system of equations (2)

. (3) leads to equalities. .at

 P.M.G / L

.Tp / t ()

From expressions (3) and C) it follows that, ev; or tp) tft. , then Afp iC Л f g, a, i.e., through the reference

resonator 3 passes a signal that is more stable in frequency than f. The coefficient of stabilization is equal to (.).

Consider the phases of the signals passing to the phase detector 9,

At the first input of the amplitude modulator 5 a signal is supplied with the phase and at the second - with the phase 15. Since the amplitude modulator 5 is with one side, then at its output we have two

0 signal: SECh carrier signal with phase 9, 5 and side signal with phase (depending on whether system 2 operates on the lower or upper side), 6 if the signal is small

5, the connection of the line with the reference resonator 3 (which is usually performed in practice) is a part of the power supplied to the input of the reference resonator 3 at the frequency t, Л fp f is reflected, while

The Q phase of the reflected signal P (Afp) depends on the offset Aff,. At the same time, the RFI signal with frequency f, being far beyond the passband of the reference resonator 3, with

With reflection, it does not acquire a phase shift depending on the Afp mismatch. Therefore, at the output of the additional mixer 10, as a result of mixing reflected signals with frequency fp and phase .4, - and signal fp with phase 4 (Afp), we have a signal with frequency D. and phase

 (

In phase detector 9, a 5 DC signal is allocated, proportional to the phase difference applied to its inputs of signals

fe, (p) (). (five

That is, proportional to the detuning of the signal & fn relative to the resonant

- ,. g ...

the frequency of the reference resonator 3 (for small detunings).

Claims (1)

1. Authorship certificate of the USSR 489193, cl, H 03 B W / 0i, 1973 (prototype).