SU1518910A2 - Device for receiving fm-signals - Google Patents

Abstract

This invention relates to radio. The purpose of the invention is to expand the range of received signals. A device for receiving frequency-manipulated signals contains mixers 1-5 frequencies, reference r-6, low-pass filters 7-9, phase shifter 10, controlled by r-r 11, band-pass filters 12 and 13, frequency doubler 14, demodulator 15 , blocks 16 and 17 phase-locked loop, dividers 18 and 19 frequencies. The goal is achieved by introducing amplitude limiters 20 and 25, multipliers 21, 22, 26 and 27, low-pass filters 23, 24, 28 and 29 and synchronous detector 30, through which the useful information transmitted using amplitude modulation is fed to the receiver. 2 Il.

Description

one

(61) 1061285

(21) 4369019 / 24-09

(22) 01/19/88

(46) 10/30/89. Bup. No. 40

(;.) 10.V. Vasiliev, V.I. Dikarev

and I.A. Zakirov

(53) 621.394.62 (088.8)

(L6) USSR Copyright Certificate № 1061285, cl. H 04 L 27/14, 1982.

(54) DEVICE / ISH OF RECEPTION OF FREQUENCY-MANIPULATED SIGNALS

(57) The invention relates to radio. The purpose of the invention is to expand the range of received signals. A device for receiving frequency-manipulated signals contains mixers 1-5 frequencies, standard r-6, low-pass filters 7-9, phase shifter 10, controlled r-r 11, band-pass filters 12 and 13, frequency doubler 14, demodulator 15 , blocks 16 and 17 phase-locked loop, dividers 18 and 19 frequencies. The goal is achieved by introducing amplitude limiters 1 and 20 and 25, multipliers 21,22,26 and 27, low pass filters 23,24,28 29 and synchronous detector 30, with the help of which personal information, before the P 11-a. help-about - large modulus g I, g y; 1 g of ai-ray body, 2 Il.

Bxof

ate

oo with

IV

The invention relates to radio; iH, can be used in the construction of receivers of analog and discrete information transmitted by complex signals with combined amplitude modulation and frequency shift keying, and is an improvement of the invention according to the author. No. 1061285.

The purpose of the invention is to expand the range of received signals.

FIG. 1 shows the structured electrical device layout; in fig. 2 - frequency diagrams for the operation of the device.

The device contains 1-frequency mixers, a reference oscillator 6, low-pass filters 7-9, a phase shifter 10, a controlled oscillator 11, a pass filter 12 and 13, a frequency doubler 14, a demodulator 15, blocks 16 and G / phase auto-tuning, dividers 18 and 19 frequencies, second amplitude limiter 20, first 21 and second 22 multipliers, fourth 23 and fifth 2A low-pass filters, first amplitude limiter 25, third 26 and fourth 27 multipliers, sixth 28 and seventh 29 frequency filters, synchronous detector

zi

A device for receiving frequency-manipulated signals is operating.

in the following way.

Received signal with amplitude modulation and frequency shift keying (AM-4Mn)

UpCt) - and, l + ni (t) cos (2; rf, pt + + c,), O t ii T,

and, Tj,,. amplitude, duration and initial phase 45 of the signal; n (t) is the modulating function

amplitude modulation;

f I + ft ,, „

 - - The average frequency of the signal (Fig. 2a);

one

t - 7 frequency of the signal, respectively, „, 1 v c p

  correspondingly

. Using a mixture / bandpass filter, the transfer of the spectrum of the pr signal to the average

f - f - f - cp

The output is a bandpass signal.

Un, l + m + tf nO,

corresponding +1 symbol;

55 where K, - odds

 + -l signal frequency, cooi - 1 symbol;

7- element duration

five

0 5 o

five

toll nocbsnoK (characters)

enters the inputs of mixers 1 and 3 frequencies. Using a mixer 1 frequency, a reference generator 6 and a band-pass filter 12, the spectrum of the AM-FSK signal is transferred to the center frequency f fcr - f, t-, where the signal frequency of the reference generator 6 (Fig. 26). The 2.4 and 5 frequency mixers, the low-pass filters 7–9, the controlled oscillator 11, and the phase shifter 10, which phase-shift by 90, form a Costa Sta ring to track the suppressed carrier.

In the AM-FMN spectrum of the signal with a continuous phase and D () (0, b, the manipulation index is suppressed, the symbol frequencies are suppressed. Therefore, the Kostas ring monitors the imaginary average frequency f, taking into account the instability, the frequencies of the input signal.

If the absolute instability of the received signal + S is greater than the separation between the symbol frequencies (f ,,), then the passbands of the low-pass filters 7-9 should be equal

p-s +.

Thus, controlled by 1 generator 11, enclosed in a costas ring, is a local oscillator with a frequency (Fig. 26)

40

Wed Thu

„, 1 v п п

. Using a 3 frequency mixer and / bandpass filter 13, the spectrum of the AM-FMN signal received is transferred to the center frequency (Fig. 2b).

f - f - f - f cp

Ha the output of the bandpass filter 13, a signal is formed

Un, l + m (t) co8 (27-fp, t-t- + tf nO, 0 t i T;

55 where K, is the mixing factor 3

frequencies;

t lh cf f cf at pch H c -M-g.

U, Cff. - Ashituda and the initial phase of the controlled generator 11, enclosed in a Kostas ring,

which simultaneously arrives at the inputs of the amplitude limiter 20 and multipliers 21,22. At the output of the amplitude limiter 20 a frequency-manipulated (FMN) signal is formed.

pch (t) u

about c ° s (2 JrfnHt + Cf,),

About t T

which arrives at the first input of the demodulator 15 and the doubler 14 frequency. If the frequency stability of the reference oscillator 6 is high, then a highly stable FMN signal is present at the first input of the demodulator 15. Doubler 14 frequencies, blocks 16 and 17 FALCH and frequency dividers 18 and 19 form a symbol synchronization system necessary for coherent demodulation, which is carried out in demodulator 15. Symbolic synchronization is based on the fact that in the energy spectrum there is an FM signal with index keypad 191 and there are discrete components at symbol frequencies (Figure 2d). The signal with the manipulation index is generated from the received signal by

doubler 14 frequency. With the help of

The PLLs 16 and IX are filtering the discrete components, and the frequency dividers 18 and 19 are designed to match the frequencies of the synchronization signals and the received FMF signal (Fig. 2e).

At the outputs of the dividers 18 and 19, the frequencies form discrete components (Fig. 2e):

U, (t) and „cos 2Т„ t + CI ,,

 g

de f

U, (t) f

22

t +

CH gG

-EG

-ag

4 / h I tn

h t-f,

which are fed to the inputs of demodulator 15 and multipliers 21,22,27, at the output of demodulator 13 a binary sequence is generated, transmitted by means of frequency shift keying.

The following voltages are formed at the outputs of the multipliers 21 and 22:

U (t) U, l + m (t) (,,) t + + tfn4, -M, .U, n-m (t) (f, + + f ,,) t + q ,, -Hp ,,;

U (t) U, l + m (t) (, T) t

+ n- Mn J + U, l + m (t) cos 2nf ,, +

+ f,) - O gg- M rm. where and, K, and ,, and „;

 transfer coefficient

knives.

Filters 23 and 24 of the lower frequencies are allocated the following voltage:

25U, (t) U, l + ra (t) (,,) t +

.

Ug (t) U, l + m (t) (f ,,) t + 30+ yy-hpts The indicated voltages after a preliminary limitation on the amplitude of one of them in the amplitude limit

u 5 (t) U cos 2irU, T-t,) t +

+ H be-H m1

multiplied by multiplier 26,

on which code the resulting oscillation is formed

U (t) (t) (, i)

+ Cfj ,, - q ,, - i-U2 l + m (t) 42f ,, - f, i-f ,,) t + 2 ((;, - Cj,.),

where U is K, U, UO.

From the resultant oscillation obtained by the low pass filter 28, it is allocated and. difference frequency (fig. -e)

lig (t). (t) (f22-f ,,) t-t-H m -.

which enters the information input of the synchronous detector 30.

The harmonic oscillations U | (t) and U2 (t) from the outputs of dividers 18 and 19 of the frequency simultaneously arrive at the two inputs of the multipliers 27, and the resulting voltage is generated at the output of KOTopoi o

and, (t) 2 (-f „) t-i-M -q ,, + U3Cos 2ir () t +

. ,,. where u {

from KOTopoi o the low-pass filter 29 separates the voltage with a difference frequency (Fig.; .e)

U, o (t) U, (f .., - f ,,) t +

+ M.

Claims (1)

This voltage is used as a reference and is fed to the reference input of the synchronous detector 30. Useful information transmitted by means of amplitude modulation is output from the output of the synchronous detector 30 to the PSU master. Invention Formula A device for receiving frequency controlled signals by auth.St. No. 1061285, characterized in that, in order to expand the range of received signals, introduced the first multiplier, the fourth low pass filter and the first amplitude limiter connected in series, the second multiplier connected in series, the fifth a low pass filter, a third multiplier, a sixth low pass filter, and a synchronous detector, the output of which is the second output of the device, the fourth multiplier and the seventh low pass filter, and the second amplitude limiter, the output of the first bandpass filter connected to the first input of the demodulator and the input of the frequency doubler through the second amplitude limiter, the output of the first frequency divider is connected to the first inputs of the first and fourth multiplies it, the output of the second frequency divider frequency connected to the first input of the second multiplier and a second input of the fourth multiplier, a first bandpass filter output is connected to second inputs of the first and the second multiplier, the output of the first amplitude limiter is connected to the second input of the third multiplier, and the output of the seventh low-pass filter is connected to the second input  synchronous detector.