RU1796906C - Radar scope - Google Patents

Abstract

The device relates to indicator and recording devices and can be used to indicate rapidly changing processes, in particular, to visually analyze and record the parameters of complex signals with combined linear frequency modulation and multiple phase shift keying (LFM-MPSK). The purpose of the invention is to increase the reliability of direction finding of a radiation source and to visually evaluate the main parameters of the received signal. The indicator device contains the first, second and third antennas 1, 2 L 3, the second, Third and fourth Broadband forces 1 PP-antennas 4, 5 and 6, the search unit 7, the local oscillator 8, the first, second and third mixers 9, 10 and 11 , the first, second and third intermediate frequency amplifiers 12,13 and 14, a detector 15, a delay element 16, a key 17, a second CRT 18, a frequency multiplier 19 by eight, a first bandpass filter 20, a frequency divider 21 by eight, a second bandpass filter 22 the first frequency detector 23, the first differentiating circuit 24, the second differentiating circuit 25, the generator -. sweep torus 26, first CRT 27. first multiplier 28, second frequency detector 30, reference voltage generator 31, fourth mixer 32, fourth intermediate frequency amplifier 33, third multiplier 34, second multiplier 35, second narrow-band filter 36, first narrow-band filter 37 , the second and first shapers 38 and 39, the second and first elements OR 40 and 41, the third shaper 42, the phase shifter 43 90 °, the third, fourth and pit CRT 44, 45 and 46. 6 ill. PY-1

Description

Phys. 1

The invention relates to indicator and recording devices and can be used to indicate rapidly changing processes, in particular for visual analysis and registration of complex signal parameters with combined linear frequency modulation and multiple phase shift keying (LFM-MPSK).

Of the known devices, the closest to the proposed one is an indicator device that searches and detects in a given frequency range Df complex signals with combined linear frequency modulation and multiple phase shift keying (LFM-MPSK), as well as visual bearing - the source of radiation of these signals in one plane, but does not provide the possibility for visual direction finding of the source of radiation of these signals in two planes.

In addition, for a reliable visual assessment of the main parameters of the received LFM-MPSK signal, the condition must be met; : U (5 -2bug Wo, where is the beat frequency;

(Oo is the frequency of the reference voltage generator. In case of frequency inequality (w $ & ak), the brightness marks will move around the circle with the difference frequency and the reliability of the visual estimation of the multiplicity m of the phase manipulation and the magnitude of the phase jumps of the received LFM-MPSF signal the circular CRT screen is sharply reduced.To eliminate this drawback, a PLL system is used to ensure the equality of the indicated frequencies,

One of the main requirements of the known device is to obtain a sufficiently low beat frequency (0 $ npvi with a relatively high intermediate frequency Otdr. The use of a conventional PLL system under these conditions does not provide the indicated frequency equality due to the unstable operation of the PLL and the presence of false captures,

The aim of the invention is to increase the reliability of direction finding of a radiation source and a visual assessment of the main parameters of the received signal.

This goal is achieved by the fact that a third antenna, a third wide-band amplifier, a third mixer, the other input of which is connected to the local oscillator output, a third amplifier, a second multiplier, and the first

a narrow-band filter, the first driver, the first element of the ILI and the modulating electrode of the fifth CRT, the vertically deflecting plates of which and the fourth CRT are connected to the output of the reference voltage generator and through a 90 ° phase shifter

- to the horizontally-deflecting plates, respectively, of the fifth and fourth CRTs, a third multiplier connected in series to the output of the second IF amplifier, a second narrow-band filter, a second shaper, a second OR element and a fourth CRT modulating electrode, a third shaper, a fourth mixer, and a fourth UPCH, while the output of the reference voltage generator through the third driver is connected to other inputs of the OR elements and through the fourth mixer and fourth UPCH - with one input of the first multiplier , the other input of which is connected to the output of the second PF, and with other inputs of the second and. the third multipliers, and the other input of the fourth mixer is connected to the output of the key.

Figure 1 presents a structural diagram of the proposed device; Fig. 2 is a structural diagram of a detector; on figs - a possible type of oscillograms: on figs 4 and 5

- timing diagrams explaining the operation of the device; Fig. b shows the principle of direction finding of the radiation source of the LFM-MPSK signals in two planes.

The indicator device contains the first, second and third antennas 1, 2 and 3, the second, third and fourth broadband amplifiers 4, 5 and 6, the search unit 7, the local oscillator 8, the first, second and third mixers 9, 10 and 11. the first, second and a third intermediate frequency amplifiers 12.13 and 14, a detector 15, a delay element 16, a key 17, a second CRT 18. a frequency multiplier 19 by eight, a first band-pass filter 20, a frequency divider 21 by eight, a second band-pass filter 22, the first frequency detector 23, the first differentiating circuit 24, the second differentiating circuit 25, the generator 26 razv wraps, the first CRT 27, the first multiplier 28, the third bandpass filter 29, the second frequency detector 30, the reference voltage generator 31, the fourth mixer 32, the fourth intermediate frequency amplifier 33, the third multiplier 34, the second multiplier 36, the first narrow-band filter 37. the second and the first shapers 38 and 39. the second and first elements OR, 40 and 41, the first shaper 42, the phase rotator 43 by 90 °, the third, fourth and fifth of the CRT 44, 45 and 46.

Moreover, the broadband amplifier 4, mixer 9, the second input of which through the local oscillator 8 is connected to the first output of the search unit 7, is connected to the output of the antenna 1, the intermediate frequency amplifier 12, the detector 15, the second input of which is connected to the output of the delay element 16, and vertically - rejection plate CRT 18, horizontal deflecting plates which are connected to the second input of the search unit 7. To the output of the amplifier 12 of the intermediate frequency are connected in series key 17, the second input of which is connected to the output detected Itel 15, frequency multiplier 19 by eight, band-pass filter 20, divider 21 by eight, band-pass filter 22, frequency detector 23, differentiating circuit 24, differentiating circuit 25, sweep generator 26 and horizontal deflecting blades EJT27, vertical the deflecting plates of which are connected to the output of the differentiating circuit 24, A mixer 32 is connected in series to the output of the key 17, the second input of which is connected to the output of the reference voltage generator 31, an intermediate frequency amplifier 33, a multiplier 28, the second input of which it is single with the output of the bandpass filter 22, the bandpass filter 29, the frequency detector 30 and the CRT modulating electrode 44, the vertical deflecting plates of which are connected to the output of the reference voltage generator 31, and the horizontal deflecting plates are connected through a phase shifter 43 through 90 ° with the output of the reference voltage generator 31. The azimuthal (goniometric) reception channel contains a series-connected antenna 2 (3), a broadband amplifier 5 (6), a mixer 1.0 (11), the second input of which is connected to the output of the local oscillator 8, an amplifier 13 (14) of the first intermediate frequency, a multiplier 34 (35 ), the second input of which is connected to the output of the amplifier .33 of the second intermediate frequency, a narrow-band filter 36 (3.7), driver 38 (39), an OR element 40 (41), the second input of which is connected through the driver 42 to the output of the reference voltage generator 31, and modulating electrode CRT 45 (46), horizontally the o-deflecting plates of which are connected to the output of the phase shifter 43 by 90 °, and the vertically-deflecting plates are connected to the output of the reference voltage generator 31.

The detector 15 contains a series-connected frequency multiplier 47 by eight, a meter 49 of the spectrum width.

a comparison unit 50, the second input of which is connected to the output of the spectrum width meter 48, and a threshold unit 51, whose second input is connected to the output of the delay line 16.

The device operates as follows.

The specified frequency range Df is viewed with the help of a search unit 7, which periodically with a ramp T according to a sawtooth law tunes the frequency of the local oscillator 8. At the same time, the search unit 7 forms a horizontal scan of the CRT 18, which is used as the frequency axis and corresponds to the span of the given frequency range Df. The key 17 in the initial state is closed.

The received signals with combined linear frequency modulation (LFM-MPSM) can be analytically written as follows:

Ui (t) Uc cos (Os t .4- y r2 + (t) + p,

U2 (t) Uc COS (Ik t + Yau t 2 + (t) + (pll U3 (t) Ue COS COc t + Lu t 2 + f) (t) + рз,

0 t TV,,

where Uc. ,, yi, (pi, rz amplitude, carrier frequency, duration and initial phase of the signals;

Af3

Y -. rate of change of frequency within the pulse;

Afd - frequency deviation; p (t) is the manipulated component of the phase, which displays the law of phase manipulation in accordance with the modulating code M (t) (Fig. 4a), and y (t) const at K t3 t (K + 1) ge and can vary abruptly at t K g, that is, at the boundaries between elementary premises (K 1, 2, ..., N-Tj;

ge N - the duration and number of chips that make up the signal duration Gu (Ti Mge). These signals from the outputs of antennas 1, 2 and 3 through broadband amplifiers 4, 5 and 6 are fed to the first inputs of the mixers 9, 10 and 11, to the second inputs of which the voltage of the local oscillator 8 of linearly varying frequencies

Ur (t) Uf cos (0t t 4- nyr t 2 + (ft),

0

where Ur, r, Tn, pr is the amplitude, initial frequency, repetition period and initial phase of the local oscillator voltage;

Df UG t Frequency change rate

I P

local oscillator

At the outputs of the mixers 9, 10 and 11, the voltages of the combination frequencies are generated. Amplifiers 12, 13 and 14 are allocated only the voltages of the first intermediate frequency

Unpi (t) - Unp cos t +

 + 7Tyt2 (t) -f pnpl Unp2 (t) Unp COS Wnpt t -f + tfyt2 (t) + 99nP2

UnP3 (t). Unp cos atop11 +

+ 7Tyt2 (t) -7Tyrt2 + pprz1 0 t: Ј%,

where Unp - ifcUcUr ;,

Kl is the transfer coefficient of the mixers; crhpi ftfc - w - the first intermediate frequency;

   - fr. Vip2 pr. rprz - p3 pr

The voltage Unpi (t) from the output of the amplifier 12 of the first intermediate frequency is supplied to the input of the detector 15, At the output of the frequency multiplier 47, a voltage is generated by eight,

L) 4 (t) Unp COS X

x (8u) nPi t 4-8 pu t 2 - 8 ug t2 -f 8.

O: Јt gi, .-. / in which phase manipulation is already absent.

The spectrum width Afs of the eighth harmonic is determined by the signal duration

(Afa -), while the width of the spectrum Afc

VIA

the received signals is determined by the duration te of their elementary premises 1

(Afc

-), that is, the width of the spectrum of the eighth

the harmonic of the signal is N times smaller than the width of the spectrum of the input signal .Afc / Af8 N.

Therefore, by multiplying the frequency of the LFM-MPSK signal by eight, its spectrum is convoluted N times. This circumstance makes it possible to detect the LFM-MPSK signal even when its power at the input of the device is less than the power of noise and interference.

The spectral width Afc of the input signal is measured using meter 48, and the spectral width Afs of the eighth harmonic of the signal is measured using meter 49. The voltages U and Us are proportional to Afc and Afe, respectively, from the outputs of meters 48 and 49 of the spectrum width input of comparison unit 50. Since U Us, a positive pulse is generated at the output of the comparison unit 50, which is fed to the input of the pore unit 51, where it is compared with the threshold voltage Unop. The threshold voltage Unop is selected so that this level does not

exceeded random interference. The indicated level is exceeded only when the LFM-MPSK signal is detected. When the threshold voltage Unop is exceeded, a constant voltage is generated in the threshold unit 51, which is fed to the control input of the search unit 7, putting it into stop mode, to the input of the delay line 16, to control input of key 1.7, opening it, and onto vertically deflecting plates

CRT 18. From now on, viewing the specified frequency range Dr and searching for the LFM-MPSF signals stops for the time of visual analysis of the main parameters of the detected LFM-MPSF signal, which is determined by the delay time g of the delay line 16. In this case, a pulse is generated on the CRT 18 screen ( frequency mark), the position of which on the horizontal scan is uniquely

determines the initial carrier frequency o) from the detected LFM-MPSK signal (Fig. 3a).

When you stop viewing the specified frequency range Of (when stopped

block 7 of the search) amplifier 9. 10 and 11 of the first intermediate frequency voltage are allocated:

Unp4 (t) Unp COS (Wnpi t +

+ 7ryt2 + y3k (t) + ph.p1.3.

Unp5 (t) Unp COS CWnpl t + + JT.yt2 + fk (t) + pnp2 J Unpe (t) Unp COS fthpi t +

-f JTyt2 + (g)) 0 t GI,

Voltage) (Fig. 4b) from the output of the amplifier 12 of the first intermediate frequency through the public key 17 is fed to the input of the frequency multiplier 19 by eight, the output of which is voltage

Us (t) Unp cos (8 (Wrtpi t 4-8 -f 8 P1),

O iStsSiit,

which is extracted by the bandpass filter 20 and fed to the input of the frequency divider 2t by eight. A voltage is generated at the output of the latter (Fig. 4c).

Ue (t) Unp cos (t -fjryt2 +, Pi), 0 t ty,

which is an LFM signal at the first intermediate frequency and is extracted by a band-pass filter 22. This voltage is applied to the input of the frequency detector 23. At the output of which it is formed

pulse (Fig. 4d), the shape of which corresponds to the law of linear frequency modulation. The specified video pulse from the output of the frequency detector 23 is fed to the input of the differentiating circuit 24, the output pulse of which (Fig. 4d) is supplied to the vertically-deflecting plates of the CRT 27 and to the input of the differentiating circuit 25. At the output of the latter, short multi-polarity pulses are generated (Fig. 4e). Moreover, the positive short pulse is started, and the negative short pulse is closed by the oscillator 26 of the scan.

The generated sawtooth voltage (Fig. 4g) is used as the scan voltage and is applied to the horizontally deflecting plates of the CRT 27. A rectangular pulse is generated on the screen of the CRT 27 (Fig. 3c). the duration of which is proportional to the duration gi of the received LFM-MFMn signal, the amplitude is proportional to the rate of change of the frequency inside the pulse, and the waveform area is proportional to the frequency deviation Aff) (Afr) y TV,) of the received LFM-MFMn signal.

To visually evaluate the main parameters of the received signal, a coordinate-time-frequency grid is applied on the screen of the CRT 27. Voltage

Uo (t) Uo COS ((Do t -t- o)

from the output of the generator 31, the reference voltage goes directly to the vertically deflecting plates, and through the phase shifter 43 to 90 ° to the horizontally deflecting plates of the CRT 44, 45 and 46, forming circular sweeps.

The voltage direct 4 W (Fig. 46) from the output of the amplifier 12 of the first intermediate frequency through the open key 17 simultaneously enters the first input of the mixer 32, the second input of which is supplied with the voltage Uoft) from the output of the reference voltage generator 31. At the output of the mixer 32, combination voltage voltages are generated. Amplifier 33 isolates the voltage of only the second intermediate frequency

Unp7 (t) Unp2 COS fWnpi t 4+ 7tyt2-f V (t),

where U.npi - 2 KlUnPu °

Wop2 - utopi k second intermediate frequency,

 Hpt - fh;

which is fed to the second input of the multiplier 28, to the first input of which the voltage Ue (t) is supplied from the output of the strip

Filter 22. At the output of the multiplier 28, a voltage is generated (Fig. 4h) U (t). Ua cos too t + pk (t) + po.

: about ,

51

where U2 2 K2Unp Unpi;

K2 is the transmission coefficient of the multiplier; which is an FMN signal on

0 to the frequency too of the reference voltage generator 31, This voltage is extracted by the bandpass filter 29 and fed to the input of the frequency detector 30. The output of the latter generates a sequence of short 5 ”pulses of different polarity (Fig. 4i), the temporal position of which corresponds to the moments of a jump phase of the received signal (figs). Formed sequence of short

0 different-polarity pulses from the output of the frequency detector 30 are supplied to the modulating electrode of the CRT 44 and modulates its electron beam in brightness. On the CRT screen 44, an image is formed in the form of several bright points located on a circle (Fig. 3b, h). The number of points determines the multiplicity of rp phase shift keying, and the angular distance between them is equal to the magnitude of the jumps

0 phase of the received LFM-MPSK signal.

UnpsW and UnpeCt) from outputs

amplifiers 13 and 14 of the first intermediate

the frequencies go to the first inputs of the multipliers 34 and 35, to the second inputs of which the voltage UnP7 (t) is applied from the output of the amplifier 3 of the second intermediate frequency. At the outputs of the multipliers 34 and 35, harmonic oscillations are generated (Fig. 5b, c) U8 (t) - U2 cos (too t + 4-),

U9 (t) U2 COS (too t + f) 0 +) 0 t gy.

1 where U2 2 K2Unp Unpi.

K2 is the transmission coefficient of the multipliers,

 - .pi 1 2 p-l - sin a - phase

a shift defining the direction to the radiation source in the azimuthal plane U. (Fig. b); ,:,

  d Au2 s - pi 2 -g sin / - phase

a shift defining the direction to the radiation source on the elevation plane; . / ...

 di, d2 - measuring; I-wavelength:

: a, ft - angles of arrival of radio waves; 05

which are separated by narrow-band filters 36, 37 and fed to the inputs of the formers 38, 39.

The voltage of the IoM (Fig. 5a) from the output of the reference voltage generator 31 is simultaneously fed to the input of the driver 42. The drivers 42, 38 and 39 generate short positive pulses at the moments of intersection of the harmonic oscillations Uo (t), Ue (t) and Ug (t ) zero level with a positive derivative, i.e. from the bottom up (Fig. 5d, e, e). These pulses through the corresponding elements OR 40 and 41 are fed to the modulating elements of the CRT 45 and 46 and modulate their electron rays in brightness. On the CRT screens 45 and 46, two bright points are formed located on the circles (Fig. Z.J.). The angular distances between the bright points equal to the phase shifts of DuЈi.

The delay time t3 of the delay line 16 is chosen so that it is possible to visually evaluate the main parameters and bearings of the received LFM-MPSK signal, observing the oscillograms on the CRT screens 18, 27, 44, 45 and 46. After this time, the voltage from the output of the delay line 16 arrives at the reset input of the detector 15 (threshold block 51) and resets its contents to zero. In this case, the search block 7 is put into tuning mode, and the key 17 is closed, i.e., is restored to its original state. From this point in time, scanning of the predetermined / frequency range DF and searching for the LF-MPSK signals continues.

If the next LFM-MPSK signal is detected, the device operates in a similar manner.

Thus, the proposed device in comparison with the prototype provides increased reliability of the visual assessment of the main parameters of the received LFM-MPSK signal. This is achieved by phase shifting the received signal to w0 of the reference voltage generator 31, and a stable waveform is generated on the screen of the CRT 44. In addition, the device of the invention makes it possible to visually evaluate the phase shifts and determining the direction to the radiation source in two planes. Thus, the functionality of the device is expanded.

Claims (1)

The claims An indicator device containing the first antenna in series, the first broadband amplifier, the first mixer, the first intermediate frequency amplifier, the key, the frequency multiplier by eight, the first band-pass filter, the frequency divider by eight, the second band-pass filter, the first frequency detector, the first differential second chain a differentiating circuit, a sweep generator, and horizontally deflecting plates of the first cathode ray tube, vertically deflecting plates of which are connected to the output of the first differentiating circuit, a delay element connected in series, a detector, the second path of which is connected to the output of the first intermediate frequency amplifier, and the output - to the vertically deflecting plates of the second cathode ray tube, the input of the delay element and another input of the key, the search unit, the other input of which is connected to the horizontal but deflecting plates. second 0 cathode ray tube and a local oscillator, the output of which is connected to another input of the first mixer, the second antenna, the second broadband amplifier, the second mixer, connected in series, 5, the other input of which is connected to the local oscillator output, and the second intermediate frequency amplifier, the first multiplier, the output of which is connected to the input of the third bandpass filter, the second frequency detector, the output of which is connected to the modulating electrode of the third cathode ray tube, whose vertically deflecting plates are connected to reference voltage generator output 5 and through a phase shifter 90 ° with its horizontally deflecting plates, the fourth and fifth cathode ray tubes, characterized in that, in order to increase the reliability of direction finding of the radiation source and to visually evaluate the main parameters of the received signal, series-connected third antenna, third broadband amplifier, third mixer, another 5, the input of which is connected to the local oscillator output, a third intermediate-frequency amplifier, a second multiplier, a first narrow-band filter, a first driver, a first OR element, and a modulating 0 electrode of the fifth cathode ray tube, the vertically deflecting plates of which and the fourth cathode ray tube are connected to the output of the reference voltage generator and through a 90 ° phase shifter 5 - to the horizontally deflecting plates of the fifth and fourth cathode ray tubes, respectively, a third multiplier connected in series to the output of the second intermediate-frequency amplifier, a second narrow-band filter, a second shaper, a second OR element and a modulating electrode of the fourth cathode ray tube , the third driver, the fourth mixer and the fourth intermediate frequency amplifier, while the output of the reference voltage generator through the third driver is connected to other my element inputs OR through the fourth mixer and the fourth intermediate frequency amplifier - with one input of the first multiplier, the other input of which is connected to the output of the second bandpass filter, and with other inputs of the second and third multipliers, and the other input of the fourth mixer is connected to the output of the key. e ooo Entrance At FIG. 4. Ie t k I i F "p5. / /