SU1356186A1 - Phase-frequency converter - Google Patents

Abstract

Invention m. used to obtain a frequency-modulated signal with a stable MF from a phase-modulated signal. The invention improves the stability of the MF output frequency-modulated (FM) signal. The frequency converter contains a phase modulator 1,. reference rr 2, block 3 of variable time delays, block 6 constant time delays, rr lf 7, second mixer 9, first mixer 10. To increase stability of the mid-frequency output FM signal, the third and fourth mixers 5 and 4 are entered, sequentially United phase detector 12 and frequency-controlled Mr. 8, between the output of the mixer 9 and the second input of the mixer 10 a resonant y 11 is inserted. 1 Il. 00 sd O) 00 F

Description

 one

The invention relates to radio engineering and can be used to obtain a frequency-modulated signal with a stable average frequency from a phase-modulated signal.

The purpose of the invention is to increase the stability of the average frequency of the output frequency-modulated signal.

The drawing shows a structural electrical circuit of the proposed phase-frequency converter.

The frequency converter contains a phase modulator, a reference generator 2, a variable time delay unit 3, a fourth 4 and a third 5 mixers, a constant time delay unit 6, a low frequency generator 7, a frequency controlled oscillator 8, a second 9 and the first 10 mixers, resonant amplifier 11, phase detector 12.

. The frequency converter operates as follows

All mixers 4,5,9 and 10 are single lane.

A high-frequency voltage is supplied to the input of the phase modulator 1 from the output of the reference oscillator 2.

U (t) U, cos (u), t 4 („), (1)

which is influenced by a modulating signal with a frequency F

P

2 strokes of the low-frequency generator 7 in the phase modulator 1 are converted into a radio signal with phase modulation

U (t) U f + () sin, nt + v,,

or

n

(2)

Where

or

i; - frequency and initial

og

the phase of the oscillation of the reference generator 2; Sd / L m is the index of angular modulation;

w - frequency deviation; SI is the frequency of the modulating signal.

At the output of block 3 of a variable time delay with a transfer coefficient K j, and a time delay IJj, there is a radio signal

(t) U, .. cos (.t-. ,,.,. nsin. (t-.p. n.rn,., cos (7.... ,,) t., "..",.

+

(3)

 rc

 CM-l

,

(6)

which is fed to the first input of the mixer 4. To the second input of this mixer, the frequency oscillations

86

generator 8, which can be performed, for example, in the form of a controlled quartz oscillator. At the exit of the mixer 4, oscillation pg is released)

total frequency (Wp.

Uc "rU with„, cos (sy + Unr) t-Hnsinn (t- -Ij,) - w

 + I / CM1.

(four)

where (j - the initial phase of the oscillations pg

frequency controlled

generator 8.

The inputs of the mixer 5 receive oscillations from the output of the reference generator 2 and the frequency-controlled generator 8. At the output of the mixer 5, the oscillation of the total frequency (u) cr + Wnr)

 pg

see cm

cos (u) ,, + w) t + c / „+ c

pg + c "gl

(five)

The oscillations from the outputs of mixers 4 and 5 are fed to the inputs of mixers 9 and 10, respectively. The blocks included in the ring connection: mixer 10, block 6 constant time delay, mixer 9 and resonant amplifier 11 form a self-oscillating system in which balance of the amplitudes in the steady state exist stable oscillations with a frequency equal to the frequency of the stabilized reference generator 2 w p Wor.

In the stationary mode, in the absence of a modulating signal, the inputs of the phase detector 12 from the outputs of the resonant amplifier 11 and the reference generator 2 receive oscillations of the same frequency Lp |. Therefore, the voltage at its output is zero and the frequency of the frequency controlled generator 8 is equal to the nominal (initial) the output value of the mixer 10 is allocated oscillation with time TOTA (Shog + III) + Y, 2 0), + YPRO,

equal to the sum of the frequencies of oscillations arriving at its inputs

.rn,., cos (7......) t. , „

 rc

 CM-l

,

where cfp is the phase shift of the oscillation in the resonant amplifier 11.

31

At the output of block 6 of a constant time delay with the transfer coefficient Kp and the delay time Dj, there will be a signal

U (t) cM4 K jjcos (2 w r + t nroH- ,, + „г„) €, -С Ц ,, + 1 / п, + VP,,

which is fed to the first input of the mixer 9. At the output of the mixer 9, an oscillation with a frequency of

(2Ы ,, + Шп,) - (shok pgo% g equal to the difference of the frequencies of oscillations arriving at its inputs

and .... and, „w t + u) sme

- (2lo „, -sh.„) + (,, + +, „Л. (8)

Of

RF

The condition of phase balance for a self-oscillating system formed by a mixer 10, a block 6, a mixer 9, a resonant amplifier 11, which are included in an annular connection, can be represented as

V or "3, - (), K

where K 0,1,2,3 ...;

Sdl cm1 smg - 30 phase shift of oscillations in the filtration circuits of mixers 4,5,9,10.

From equation (9), one can find the expression for the oscillation frequency of the ring oscillator, formed by a mixer 10, a block 6, a mixer 9, a resonant amplifier 1 1, in the form

  oh

.firol- j-lJ jizJLfi

3

(ten)

If Wp., / U) (, r., Then with the help of block 3 of the variable time delay, the condition

 og

Thus, in stationary mode, at the output of the frequency controlled oscillator 8, there is an oscillation with a nominal frequency and. which is the average or carrier frequency of the output signal of the phase-frequency converter.

In the dynamic mode, if there is a phase modulator 1 voltage at the control input of the modulating signal, the input phase shift l I / changes according to the law of changing the modulating signal msinJ Ct-tn

64

and the oscillation frequency in the self-oscillating system formed by the included in the annular connection of the mixer 10, unit 6, mixer 9, resonant amplifier 11, deviates relative to the nominal value according to the law of change of the modulating signal, since the phase balance conditions are fulfilled at other frequencies. At the output of the phase detector 12, a control signal appears, which is supplied to the frequency controlled oscillator 8, and its frequency is changed by an amount that the phase balance condition in the above self-oscillating system is performed at the same frequency Wp. The condition of phase balance in this case takes the form

  og shr „+ L w ,,) And ,,

-msin5 (t- ,,) + i k.

(AND)

-3g pv with the magnitude of the phase shifts

,

С „, (, + ш„ ,. „)

W or pgo-32 P remains almost unchanged. From

expressions (9) and (11) of the following: it is that the change in the frequency of the frequency controlled oscillator 8 due to the application of the voltage of the modulating signal, i.e. due to the supply of a signal with phase modulation to the input of the mixer 9, is equal to

msinflft - € 5,)

. (

12)

-3

The delay time in the feedback loop is chosen such that with a slight deviation of the frequency of the input signal, the signal at the output of the phase-frequency converter has a large frequency deviation and is determined mainly by the value of the delay time of the constant-time block 6.

Claims (1)

Invention Formula A phase converter containing a phase modulator whose modulating signal input is connected to the output of a low-frequency generator, the input of a modulated signal to the output of a reference generator, and the output to an input of a variable time delay unit, as well as serially connected first mixer, constant time delay unit and a second mixer, characterized in that, in order to increase the stability of the average frequency of the output frequency-modulated signal, between the output of the reference oscillator and the first input A third mixer is inserted into the first mixer, a fourth mixer is entered between the output of the variable time delay block and the first input of the second mixer, and the Editor N. Kishtulinets is sequentially entered between the output of the reference generator and the second input of the third mixer Compiled by G, Zakharchenko Tehred M.Didzh Corrector A. Ilyin Order 5810/53 Circulation 900 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab ,, d, 4/5 Production and Printing Enterprise, Uzhgorod, st. Design, 4. A single phase detector and a frequency controlled oscillator, a resonant amplifier is inserted between the output of the second mixer and the second input of the first mixer, while the output of the frequency controlled oscillator is connected to the second input of the fourth mixer, the output of the resonant amplifier is connected to the second input of the phase the detector, and the output of the frequency controlled oscillator is the output of the phase-frequency converter.