SU1661661A1 - Panoramic receiver - Google Patents

Abstract

The invention relates to radio engineering and can be used for searching and detecting phase-shift keyed signals, as well as visual assessment of their carrier frequency. The purpose of the invention is the detection and selection of phase-shift keyed signals and the expansion of the range of their frequency search without extending the range of the frequency tuning of the local oscillator. Panoramic receiver contains antenna 1, sweep generator 2, local oscillator 3, mixer 4, intermediate frequency amplifier 5, detector 6, frequency multiplier 7 by eight, spectrum width meters 8 and 9, comparison unit 10, threshold unit 11, key 12, line 13 delay, multiplier 14, bandpass filters 15 ₁ - 15 ₄ , amplitude detectors 16 ₁ - 16 ₄ , video amplifiers 17 ₁ - 17 ₄ , CRT 18 ₁ - 18 ₄ . 1 il.

Description

The invention relates to radio engineering and can be used to search and detect phase-shift keyed (PSK) signals, as well as a visual assessment of their carrier frequency.

The aim of the invention is to expand the functionality by detecting and selecting FMN signals and expanding the range of their frequency search without expanding the range of frequency tuning of the heterozyme.

: The block diagram of the panoramic receiver is shown in the drawing.

J The panoramic receiver contains the output of the antenna 1, oscillator 2 sweep, local oscillator 3, mixer 4, amplifier 5 of the intermediate frequency, detector 6, frequency multiplier 7 n ^ eight, first meter 8 of the spectrum width, second meter 9 of the spectrum width, comparison unit 10, threshold block 11, key 12, delay line 13, multiplier 14, η processing channels (n = 4), each of which consists of a 1 $ bandpass filter, amplitude detector 16, video amplifier 17 and a vertical electrode of a cathode ray tube ( CRT) 18 ..

The panoramic receiver contains sequentially coupled oscillator 2, a local oscillator 3, a mixer 4, the second input of which is connected to the output of the antenna 1, an intermediate frequency amplifier 5, an eight frequency multiplier 7, a spectral width meter 9, a comparison unit 10, the second input of which is through meter 8 the width of the spectrum is connected to the output of an intermediate frequency amplifier 5, a threshold block 11, a key 12, the second input of which is connected to the output of an intermediate frequency amplifier 5, a delay line 13, a multiplier 14, the second input of which is connected to Odom key 12, and η processing channels. Each of the latter consists of a series-connected band-pass filter 15, an amplitude detector 16, a video amplifier 17 and a vertical CRT electrode 18, the horizontal electrode of which is connected to the second output of the scan generator 2.

The panoramic receiver works as follows.

Viewing a given frequency range Df is carried out using a sweep generator 2, which periodically with a sawtooth law tunes the frequency of the local oscillator 3. At the same time, sweep generator 2 generates a horizontal scan of a CRT 184-184, which is used as the frequency axis, and its length corresponds to the frequency span range Df. The key 12 in the initial state is always closed.

Received FMN Signal

U _c (t) = U ₀ . cus ^ ct + Q / t) + CP3 ^{Oit <T} c> where U _c , C0 _s ,

T _e and Cp _c are the amplitude carrying the frequency, duration, and initial phase of the signal) (D ' _k (t) is the manipulated component of the phase that displays the law of phase manipulation, and ΐΡκ (t) = const for k £ _n <t <( k + 1) 0 _and u can change abruptly by yts> for t = kC „, i.e. at the boundaries between elementary premises (k = 1, 2 ..... N-1);

+ _and and N is the duration and number of chips that make up the signal with a duration of T. (t _s = k £ _u ), from the output of the antenna 1 it goes to the first input of the mixer 4, to the second input of which the voltage of the local oscillator 3 of a ramp frequency

I

U _r (t) = u _r . C0s (co _r -t + 1T y, t ^{? +} Q _r )) 0 ¢. t * T _h , t

where is U _r , G? _r

T _rt and Cp _r — amplitude, initial frequency, repetition period and initial phase of the local oscillator voltage;

J, = j- is the rate of change of the local oscillator frequency (rate of change of the first harmonic of the local oscillator frequency).

At the output of the mixer 4, the voltages of the combination frequencies are generated. The amplifier 5 isolates the voltage of the intermediate (difference) frequency

I.

^ Pr, 4) ⁼ Unp ' ^COS [^ np ^{t + £} / | <4) ^0it4T e, ^where pr 2 K <U e U _f ;

- gear ratio of the mixer;

СО _П р ⁼ С0 _с ~ 6) r ~ intermediate frequency;

Ch'lr Ch's ⁼ H ~ ^{r _} intermediate to 'tial phase, which is a signal with a frequency modulation of the kombinirovannoy'lineynoy and phase shift keying. This voltage is supplied to the input of the detector 6, consisting of a frequency multiplier 7 by eight, meters 8 and 9 of the width of the spectrum, block 10 comparison, threshold block 11 and key 12.

At the output of the frequency multiplier 17 by eight, a voltage is generated

U, (t) = U _np . cos [8Q t - 8 ^ V, t '+ ⁺ 8ίρ _ηρ ], 0 6t ^^.

Since 8 (^ (0 = 0.8 5 when receiving a signal with a single phase-shift keying (ip _K (t) = 0.5), 8Cp _fc (t) = 0.45, Sir, 125 when receiving a signal with double phase shift keying ((p / t) = о, |, 5, 3/45), 8 (p _K (t) = 0.25, 45, 65, 85, 105, 125, 145 when receiving a signal with three times phase manipulation (4 \ (t) '

° ’

3 5 a- 3 a- 7 '2' 5 I * ' ¹¹ ' 4 ^p '2 * 4 *' ^τ θ in the indicated oscillation phase manipulation is already absent.

The width of the spectrum of Af _{4 of the} eighth harmonic is determined by the duration T _{e of the} signal (A f ₄ = -), while the width of the spectrum of Af _{c of the} FMN signal is determined by the duration of its elementary transmissions (Af _c = -χ · -), l. spectrum width of the eighth harmonic. the signal is N times smaller than the spectrum width Af _{c of the} input signal: I.

those.

Α-ίε. = k

Af ₄

Therefore, when the frequency of the FMN signal is multiplied by eight, its spectrum is collapsed N times. This makes it possible to detect the FMN signal even when its power at the receiver input is less than the noise power,

The spectral width Af _{c of the} input FMN signal is measured using meter 8, and the spectral width Af, of the eighth harmonic of the signal is measured using meter 9. Voltages U and U, proportional to A f _s and Af, respectively, from the outputs of meters 8 and 9 of the spectral width 10 two inputs of block 10 comparison. Since Uи ,, then a positive voltage is formed at the output of the comparison block, which exceeds the threshold level U _no in the threshold block

11. The threshold level U _then is chosen so that it does not exceed random interference. When the threshold level U _πσρ is exceeded, a constant voltage is generated in the threshold block 11, which is supplied to the control input of the switch 12, opening it.

In this case, the voltage П _П р, (t) from the output of the intermediate frequency amplifier 5 through the public switch 12 is simultaneously supplied to the first input of the multiplier 14 and to the input of the delay line 13, the output of which produces voltage = f ^ np · ^{C <JS} [^ 6 ) _n p (t — .L ^) + ^ (t ~ - + o ^ t <T _c , where is the delay time of the delay line 13 “.

The output of the multiplier 14 is formed voltage

Ug <(t) = U _& cosiooot + ^ t-Cfc),

Τ, where U5- = j K _g U _n ^z _p ;

- the transfer coefficient of the multiplier 14,

С0 ^ ₍ = 25 J, 5 - beat frequency;

cp _r , (t) = Cp _K (t - \) - q> _K (t), = 6¼ VWr

The carrier frequency of the beat voltage (0 $, (t) &? §, = 25 ^ | ip const.

Consequently, for a fixed delay time of 5 ^, a multi-frequency beat signal is generated at the output of multiplier 14, the carrier frequency of 60 g ^{r of} which depends on the rate of change of the frequency y, '(i = 1, 2, ..., η) of the local oscillator 3. The rate of change the frequency of the converted signal supplied to the input of the autocorrelator depends on the harmonic number of the local oscillator frequency 3, interacting with the carrier frequency of the received FMN signal.

The tuning frequency of the band-pass filter 15, is chosen equal to the tuning frequency of the band-pass filter 15 ^ is chosen equal to 10 a | the tuning frequency of the bandpass filter 15 ^ is chosen equal to ⁼ 2 and J _n 5y> 15 where ^ _n = ⁿ “is the rate of change of the ηth harmonic of the local oscillator frequency.

The voltage U (t) from the output of the bandpass filter 15, is fed to the input of the amplitude detector 16, where it is detected and, after amplification in the video amplifier 17 _{is applied to the vertical electrode of the CRT 18, on the screen 25 of which a pulse is generated (frequency mark). The position of the frequency mark on the horizontal scan of the CRT 18, uniquely determines the carrier frequency C0 _{from the} received FMN signal.

Therefore, the harmonic number of the local oscillator frequency 3, with which the carrier frequency of the received FMN signal interacts, is determined by the size of the band-pass filter of that channel, on the CRT screen of which a frequency mark is observed.

Claims (1)

Claim A panoramic receiver comprising a receiving antenna in series, a mixer, the second input of which is connected through a local oscillator to the first output of the sweep generator, an intermediate frequency amplifier, as well as an amplitude detector, video amplifier and cathode ray tube, the horizontal electrode of which is connected to the second output of the sweep generator, characterized the fact that, in order to expand functionality by detecting and selecting phase-shifted signals and expanding the range of their frequency search, an eight frequency multiplier, two spectral width meters, a series-connected comparison unit, a threshold block, a key, a delay line and a multiplier, a band-pass filter, a second-band-pass filter in series, a second amplitude detector, a second video amplifier and a second cathode ray tube, horizontal the electrode of which is connected to the second output of the sweep generator, the output of the intermediate frequency amplifier is connected to the input of the first spectral width meter and to the input of the frequency multiplier by eight , the input of the second spectral width meter is connected to the output of the frequency multiplier by eight, the outputs of both spectral width meters are connected to the inputs of the comparison unit, the second key input is connected to the output of the intermediate frequency amplifier, the second input of the multiplier is connected to the key output, and the output of the multiplier is connected to the inputs of both bandpass filters, the output, the first of which is connected to the input of the first amplitude detector.