SU1337808A2 - Oscillographic phase meter - Google Patents

Abstract

The invention can be used in radar and communications where signals with combined amplitude modulation and phase shift manipulation are widely used. The purpose of the invention is to expand the functionality of the device. Phase meter contains sweep generator 1, electronic switch 2, local oscillator 3, mixer 4, intermediate frequency amplifier 5, switch 6, delay line 7, drive 8, CRT 9 and 13, reference voltage generator 10, phase shifter 11 at 90 ° ;, amplifiers 12 and 14 and amplitude limiter 15. The introduction of multiplier 16, band-pass filter 17 and CRT 18 allows not only to estimate the phase shift between two harmonic signals and to search in a predetermined frequency range of phase-shifted signals and visual assessment of their main parameters, but also provide a search in a predetermined frequency range of signals with amplitude modulation and signals with combined amplitude modulation and phase shift manipulation and a visual assessment of their main parameters. 3 il. S SL T WELL GYU

Description

The invention relates to a radio metering technique and can be used in radar and communication, where signals with a combined amplitude modulation and phase maneuver (LM-FMN) are used.

The aim of the invention is to enhance the functionality of the phase meter by searching the frequency of a signal with a combined amplitude modulation and phase shift keying.

Figure 1 presents the structural diagram of the proposed phase meter; FIG. 2 shows oscillograms for signals with different multiplicity of phase shift; on FIG. 3 is a storage scheme of the drive.

The phase meter contains a series-connected sweep generator 1, an electronic 1 1 {1 switch 2, local oscillator 3, mixers 4, intermediate frequency amplifier 5, switch 6, delay line 7, drive 8, first CRT 9, reference voltage generator 10, Phased diode 11 to 90 , amplifier 12, second CRT 13, amplifier 14, amplitude limiter 15, multiplier 16, band-pass filter 17 and third CRT 18.

Drive B (FIG. 3) contains multipliers l, 19, and 19a, frequencies by two, four and eight, respectively, analyzers 20, 2 () (, 20. ,, ,, 20 j spectrum, blocks 21, j 21 and 21 comparisons, threshold elements 22 ,, 22 ,, and 22, and the element of SHI 23.

In the oscillographic phase meter in series connection1 generator

1 sweep, electronic switch 2, local oscillator 3, mixer 4, the second input of which is connected to the phase meter input, intermediate frequency amplifier 5, amperage limiter

15 and the accumulator 8, the second input of which is connected via this delay line 7 by the output, and the output is connected to the second input of the electronic switch

2 and a vertical electrode of a CRT 9, the horizontal electrode of which is connected to the second output of the sweep generator 1. A key 6 is connected in series to the output of the amplitude limiter 15, the second input of which is connected to the output of accumulator 8, the multiplier 16, the second input of which is connected to the input of the phase meter, bandwidth 17 and vertical CRT 18, horizontal

the electrode of which is connected g ntor) 1m generator output 1 scan. A phase shifter 11 by 90, an amplifier 12 and a horizontal CRT electrode 13 are connected in series to the output voltage of the reference voltage generator 10, the vertical electrode of which is connected via an amplifier 14 to the output of the reference voltage generator 10, and the control electrode is connected to the output of switch 6.

The principle of operation of the proposed phase meter is based on a search in a given

frequency range Df of the signal with combined amplitude modulation and phase shift keying and visual evaluation of its main parameters: carrier frequency,,, phase jumps uq, phase shift multiplicity m, and amplitude modulation law M (t) on the screen of three CRTs. The phase meter works as follows

The viewing of a given frequency range Df is carried out with the help of oscillator 1, which periodically, with a period Tf, according to sawtooth law, tunes the frequency of the local oscillator 3.

At the same time, generator 1 forms a horizontal scan of CRT 9 and 18, which is used as a frequency axis, and its length corresponds to the frequency span of the frequency range.

Received signal with combined modulated amplitude modulation and phase shift keying (AM-FMN)

and (O 41 l + M (c)) + cf.

where Uj, u ,, is the amplitude, the carrier frequency and the initial phase of the signal;

M (t) is the amplitude modulation modulating function;

4 j ((t :) -, a manipulated component of the phase, representing the law of phase manipulation, and g4t (t) const with

kr .; t () and can be changed by jumping to ULf at, i.e. on the boundaries between the parcels (, 2, .., N-1); - the duration and the number of elementary parcels, of which

five

P

the signal is of duration T (T.Ne), is fed to the first input of the mixer 4, the second input of which is supplied with the voltage of the hetero / PC 3 linearly variable frequency

.g

Mr. W4J,

cos (cO t -Tljt + Cf),

where and

g

U

g

Chg

the amplitude, frequency, and initial phase of the heterodyne voltage;

the rate of change of the frequency of the local oscillator. At the output of the mixer 4 is formed

voltage combination frequencies.

Amplifier 5 releases voltage.

only intermediate frequency

Y t

and, p (t) 4J, p Um (0,, pt- -tf tbTTjft + q .p, 1- K.U.Jr;

K, is the coefficient (1) of the transfer agent of the mixer; C0n. intermediate frequency;

H g, r h s-h g,

which, after accumulating and exceeding the threshold level and pores in the accumulator 8, acts on the control input of the electronic switch 2, from the key, the local oscillator 3 from the generator 1, on the control input of the key 6, opening it, and on the vertical electrode. CRT 9, the horizontal electrode of which is connected to the second output of the generator 1. From this point on, the search process for AM-FMn signals ceases.

The voltage Upp (t) from the output of the amplifier 5 of the intermediate part is fed to the input of the amplitude limiter 15, the output of which forms a voltage

and, (About UoCos Q „pt + c, (t;)

in which amplitude modulation is eliminated and only phase shift keying (FMN) is present.

If the OFMS signal (t) is 0.1 and arrives at the input of the accumulator 8, then at the output of the multipliers 19 ,, 19 2. and 19j the frequencies oscillate, respectively:

U, (t) Uo Cos (2GDnpt-27yt + 2efnp); Ui (t) Uo cos (4Unp t-47j t% 4q np); and, (c) and „. co5 (8i „p t-8: ryt + 8cfn (,);

Since 2t; (t) 0.27 j 4cp (t) —0.47; 8cf (t) 0.8 Tg, then in these oscillations the phase manipulation is already absent, the width of the spectrum of the second bfg, fourth 4 and eighth U fg harmonics is determined by the duration of the signal

Tj. l Af 4 ufg 1 / T, while the width of the spectrum if. The OFMS signal is determined by the duration of its elementary assignment (), i.e. the width of the spectrum of these harmonics is N times less than the width of the spectrum of the input signal

N

Consequently, when multiplying the frequency of the OFMS signal by two, a cup and eight, its spectrum is folded N times. This circumstance makes it possible to detect the OFMS signal, even when its input power is less than the noise power. Width

The spectrum of the input signal is measured using a spectrum analyzer 20; the spectral width of the second bf, fourth d and eighth harmonics

eight

The signal is measured using 20, 20, and 20 spectrum analyzers. Voltages and, Uj and and, proportional, f4 6, respectively, from the outputs of analyzers 20, 202 and 20 of the spectrum are fed to the first inputs of blocks 21, 21 and 2C of the comparison, to the second inputs of which voltage is supplied and from the output of the analyzer 20 spectrum, proportional to uf ,. Since,, and,, then at the output of blocks 21 ,, 212 and 21J positive pulses are generated that exceed the threshold level in threshold elements 22 ,, 22 and 22, and through the element OR 23 arrive at the output.

If the input of the accumulator 8 receives a signal with a double FM and

a) o, -1-, 7, - | -7, then

at the output of the multiplier 19f, a phase-manipulated signal is formed by two, and at the output of multipliers 19, and 19, frequencies of four and eight are formed)) HU} (t), respectively, i.e. in these channels, the input signal is convolved.

If the input of the accumulator 8 receives a signal with a threefold phase shift keying

3

four

LvP. (T) 0,. ,

then the convolution of its spectrum is carried out only at the output of the multiplier 1 Eg, frequency by eight. In this case, a positive voltage is generated only at the output of the comparison unit 21j.

Accumulation time and threshold level and

pore

in drive 8 choose

Thus, 1 this level did not exceed random interference. At the same time, a pulse (frequency mark) is formed on the screen of the CRT 9, whose position on the horizontal scan odnally determines the unopposed frequency u) from the received signal with a combined amplitude modulus and phase shift keying (Fig. 2a).

For a visual assessment of the magnitude of the phase jumps dsr and the multiplicity of phase manipulation m of the received sig} 1al, CRT 13 with a circular scan is used, and the circular scan is formed using the reference voltage generator 10, the frequency of which is equal to the intermediate frequency of the received signal: the generator 10 enters through the amplifier 14 to the vertical electrode and through the phase shifter 1 1 and usi1P1tel 12 - to the horizontal electrode of the CRT 13

the control electrode of which, via the open key 6, receives the intermediate frequency Ug (t) signal from the output of the amplitude limiter 15. Therefore, the voltage of the generator 10 is used to form a circular sweep of the CRT beam 13, and the received FMN signal of the intermediate frequency carries the module its brightness. On the screen of a CRT 13 an image is formed in the form of several bright dots located on the circumference (Fig. 2B, d, e). The number of points determines the multiplicity of phase manipulation m, and the angular distance between them is equal to the magnitude of the phase jumps of the received signal. With unequal frequencies of co and cpps, the toughness marks will be shifted around the circumference of the (partial) tonal frequency.

For a visual assessment of the ms, the M-Heit function M (On the amplitude modulation of the received LM-FMN signal

CRT 18 is used with a linear scan. In this case, the FMP-signal U (t) from the output of the amplitude limiter 15 is open. the key 6 is fed to the second input of the multiplier 16, on

the first input of which is supplied by the received AM-FMN-signal U, (t) from the input of the phase meter. As a result of multiplying these signals at the output of the multiplier 16 (a resultant oscillation is produced

L j (t) Uj UM (t). cosCuvt + .Vt: +1 + 1 + M (t; I. s o s (2 cj - L) t + 2 p (t) - and y + 2tF ,,,

Where

U and.

K., - transfer coefficient

knife,

from which the bands1.1m filter 17 allocates a voltage of the difference frequency

P

, (t;) (t) J cos (cj t + 7: yt + (f,).

B

0

0

five

0

five

in which phase manipulation is already absent, and Tojn, Ko is present amplitude modulation at the frequency of the local oscillator 3. This voltage from the output of the strip 11) 17 n; steps onto the vertical electrode 3.11 18, on the horizontal 1,1y electrode of which is supplied voltage from the second to the output of the generator 1 sweep. As a result, on a CRT screen, 18 g1o is an oscillation frame of a yVt 1 signal in question (t) (| bi2b).

Time G, delay; when the delay 7 is chosen so that it is possible to visually evaluate the main parameters of the received / V 1-FMP signal, the oscillograms are observed on CRT screens 9, 13 and 18. After this time has passed, the output / delay voltage is applied to the reset input of the accumulator 8 and resets its element 22 ,, 222 and 22, at the beginning: P) But the state. In this electronic; switch 2 is transferred to its original state, which is hetero; cn 3 turns out |, is, h connected to the output / y –ene15ato15a 1 sweep, and the key 6 is zak 1, that is, transferred to its original state; e. From this point on, the viewing of a given frequency band 1 band 11 a i search AI-iE MH-t; nr-HcLioi prod (5.you jump, if the next LM-Fnn signal is detected, the phase meter works in a similar way.

If a QPSK signal arrives at the phase meter input, its parameters are visually evaluated on CRT screens 9 and 13.

If a 1-signal enters the phase meter input, then its parameters are visually evaluated on CRT screens 9 and 18.

Thus, the proposed oscillographic phase meter compared with the prototype allows not only to estimate the phase shift between two harmonic signals and search in a given frequency range of phase-shifted signals and visual assessment of their main parameters, but also to search for a given frequency range of signals with amplitude modulation and signals with combined amplitude modulation and phase manipulation and a visual assessment of their main parameters (carrier frequency, magnitude of phase jumps, is a multiple of st phase

manipulation and chacamplitude modulation), which expands the functionality of the oscillographic phase meter.

Claims (1)

Invention Formula Oscillographic phase meter on the auth.St. No. 1247778, characterized in that, in order to expand the functionality of the phase meter by searching the frequency of a signal with combined amplitude modulation and phase shift, a serially connected multiplier, a bandpass filter and a vertical electrode are inserted into the third CRT, the horizontal electrode of which is connected to the second output of the sweep generator, as well as the amplitude limiter connected between the output of the intermediate frequency amplifier, the first input of the key and the second input of the drive. 00 / ilf ff t f h 2 x.f Editor A.Lezhnina (puz.Z Compiled by L.Voronina Tehred I.Popovich Proofreader E.Roshko Order 4126/43 Circulation 730 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production ((: creative polygraphic enterprise, Uzhgorod, Projecto st., 4.