SU1539676A1 - Oscillographic phase meter - Google Patents

Abstract

The invention relates to a radio measuring technique and can be used to visually estimate the carrier frequency and the type of signal modulation. The purpose of the invention is to expand the functionality achieved by introducing into the device three channels of intermediate frequency signal processing, each of which contains cathode ray tubes 16, serially connected frequency multiplier 13, frequency divider 14, amplitude detector 15. In processing channels when multiplying the intermediate frequency by two , four, eight, the spectrum of the phase-manipulated signal is "collapsed" and transformed into single spectral components. The drawing shows sweep generator 1, local oscillator 3, mixer 2, intermediate frequency amplifiers 4 and 12, accumulator 5, delay line 6, indicator 7, sawtooth generator 8, key 9, local oscillator 10, mixer 11. 2 Il.

Description

The invention relates to a radio metering technique and can be used to visually estimate the carrier frequency and the type of modulation of the received signal.

The aim of the invention is to expand the scope by visually assessing the type of modulation and the main parameters of the received signal.

FIG. Figure 1 shows the structural diagram of the oscilloscope of the Cesky phase meter; in fig. 2 - oscillograms for signals with different types of modulation.

The oscillographic phase meter contains sequentially connected sweep generator 1, local oscillator 2, mixer 3, the second input of which is connected to the device input, intermediate frequency amplifier 4 and drive 5, the second input connected to the output of the delay line 6, and the output to the second input of the generator 1 scanner and a vertical electrode CRT 7, the horizontal electrode of which is connected to the second output of the generator 1 scan. A generator 8 of the sawtooth voltage, a switch 9, a second input of the generator 8 are connected to the output of the delay line 6, the first is connected in series with the heterodyne 10, a JJ mixer, the second input of which is connected to the output of the switch. 9, amplifier J 2 second intermediate; frequencies and three signal processing channels, each of which consists of a series-connected frequency multiplier 13, (13, 1 3 Oe), a divider 14.04.2, 14E), an amplitude detector 151 (151, 153), and a vertical CRT electrode 16, (164, 163), the horizontal electrode of which is connected to the output of the sawtooth generator 8. In the first signal processing channel, the second intermediate frequency is multiplied and divided by two, in the second - by four, and in the third - by eight.

The principle of operation of the device is based on the search in the specified frequency range of the signal and the visual assessment of the type of modulation and its main parameters. Oscillographic phase meter works as follows.

Viewing a given frequency range is performed using a sweep generator 1, which periodically, with a sawtooth period, tunes the frequency of the local oscillator 2. At the same time, the sweep generator 1 forms a horizontal scan of the CRT 7, which is used as a frequency axis, and its length corresponds to the frequency span range.

If the phase meter input receives a signal with a single phase shift keying (OPMN), which, after accumulating and exceeding the threshold level in accumulator 5, affects the control input of the sweep generator 1, switching it to the stop mode, opening control key 9, at the first input of the generator 8, including it, and at the vertical electrode of the CRT 7, the horizontal electrode of which is connected to the second output of the sweep generator 1, then from this point in time the search for signals stops at the time of visual analysis that determined by the delay time of delay line 6.

The accumulation time and threshold level in accumulator 5 are chosen such that this level is not exceeded by random interference. In this case, a pulse (frequency grid) is formed on the screen of the CRT 7, whose position on the horizontal scan uniquely determines the vote carrier frequency of the received FMN signal (Fig. 2).

For a visual assessment of the modulation type (manipulation) of the received signal, a second frequency conversion of the received signal and three channels of signal processing of the second intermediate frequency are used.

At the outputs of the frequency multipliers by two 13 ,, four 13 and eight J3j, corresponding oscillations are formed, in which the phase manipulation is already absent. The spectral width of the second 4f, fourth df4 and eighth Ufa harmonics is determined by the duration of the Tc signal (df4 df4 dfe

 -). Then the width of the spectrum DЈs

Those

The OFMS signal is determined by the duration of {its elementary positions

I

LOK (uf with g).

t- and

Consequently,

when multiplying the second intermediate frequency by two, four and eight, the spectrum of the signal is collapsed 1 ° C ufc ufc

N times (

& t uf4

df

N)

t

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and is transformed into a single spec. T 3

Smaller components, which are sent after TFMN, fK () 2 divisions in frequency dividers 14, 14, $ 3 7

145 and detection in amplitude, 4 2 4 T ° At the outputs of Y ™

detectors 15 ,, 152, 15E view-frequency knives 13, two and 13

CRT 16 ,, 162, 163 screens are found on four forms DFMn and OFMn sig-1

(Fig. 2, a, b, c). These are the circumstances whose spectra are observed on

and is a sign of the arrival on the CRT screens 161 (Fig. 3g) and 167 (Fig. 2e).

the input of the phase of the OFMn signal, which is correspondingly, and at the output of the multiply one, the multiplicity of the phase key of the frequency of 1 Зe by eight is formed

m 2, and the magnitude of the jumps is the phase harmonic oscillation U3 (t), the spectra If - IT is the polar component of which is observed the delay time C3 of the delay line 6 is given on the screen of the CRT 1 63 (Fig. 2). The short ones are chosen so that Phase manipulation m in this visually evaluate the main parameters is 8 (t 8), and the magnitude of the received OFMS signal, observed ff oscillograms on screens 7, 16, phase jumps / n. 164, 16E. the input of the phase meter is supplied with voltage from the output of line 6 of the delay 20 signal with frequency manipulation from the post It falls on the second input of the generator by an 8-shift (MMC), then its analogous voltage, including it, can be presented lytically from the back of the storage device 5, in a resetting way.

syva its contents in the initial soy-t g.

that notion. In this case, the generator 1 is deployed; 25 MO Vc-cos L2 "fcpt + 44t) + ki is switched to the search mode, and the key

9 closes, i.e. translates to + t4j -t i lc its original state. From now on, viewing a preset frequency

range and search for signals for 30 seconds, the amplitude, duration. In the case of detecting the next initial phase of the SPSMK signal, the phase meter operation

walks in the same way. . No. changing in time, the generator 8 forms Phase function,

ruts sawtooth voltage, duration -f 1 1 - average frequency sigal. whose value is determined by time

C3 delay line 6 delay. Specified - 1 Wed

. The required voltage for the spectrum is ---- - the frequency corresponding to the decomposition of the received signal and the symbol + |: 1 |,

la.40fg fcp +

If the input of the phase meter is 1

, + -t- - - frequency, corresponding to the signal with a double phase mani- 4y ,. ,

g „, ..,. - t. and schA symbol - J.

UWH, K (OO, L, jf, phase function in time for each | (T, then at the output of the multiplier, the 45th symbol interval changes Jlinearly. During one symbolic time i 3, the phase increment interval is + f. 0) TG, 21G, 3, the spectrum2 of which is observed on the CRT screen (the -if t oo interval has a phase function 16 (FIG. 2d), and the multiplies-H at the outputs (O the frequency punc- tors are 132 by four and 133 by the 50-line function. The index of frequency eight is formed by the corresponding impulses t: the signal is equal to the harmonic oscillations and U2 (t), HU3 (t), D (ff) - which are observed on the CRT screens 16j iw 2 (fig.2d) and 163 (fig.2e). Parameters When multiplying the frequency of the received-received DPSK signal is estimated by wc signal for two, four and two in a similar way. | seven its spectrum is transformed into If the phase meter input receives two spectral components with an input signal with a triple phase manipulator D 1,2,4 respectively

(Fig. 2k, l, m). By the mutual arrangement of the spectral components and the mean frequency of the received MMC signal (it is visually mounted on the screen of the CRT 7), the frequencies f19 f and the duration of the elementary premises of the 1st (symbol intervals) can be visually assessed.

If a phase-modulated signal (DFM) arrives at the phase meter input, it has three instantaneous frequencies, namely

f - f I - - - 1

CP

Tv

f f +

H cf + 4C

uh

cp

then at the output of frequency multipliers by

four

1G and eight

133 its spectrum is transformed into three spectral components (Fig. 2o, p). These spectral components are observed on CRT screens 16 2 and 16e. On the screen of a CRT 16, the spectrum of a PMM signal is observed (FIG. 2n).

If the input of the phase meter receives a signal with frequency modulation with rounding (HMS), which has five instantaneous frequencies

f. f

one

CP

80 1i

f „f

cp

op

4V

-cp

"I

then, at the output of the frequency multiplier 1 3j, eight spectral components are formed by eight. These spectral components are visually evaluated on a CRT 1 6 3 screen (Fig. 2m). On the CRT screens 16, and 162, the spectra of the received HMS signal are visually observed (Fig. 2c, c).

Thus, the proposed oscillographic phase meter, compared with the base object, provides not only a search for signals in a given frequency range and a visual assessment of their carrier frequency, phase shift multiplicity and magnitude of phase jumps, but also a visual estimate of the type of modulation (manipulation) received signals. Thus, the functionality of the phase meter is significantly expanded.

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five

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five

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Claims (1)

Invention Formula An oscillographic phase meter containing a series-connected local oscillator, a mixer, the second input of which is an analyzer input, an intermediate frequency amplifier and a drive, the second input of which is connected to the output of the delay line, and the output connected to the input of the sweep generator, to the input of the delay line, to the vertical CRT electrode and to the second input of the key, the first input of which is connected to the output of the intermediate frequency amplifier, the horizontal electrode of the CRT is connected to the output of the sweep generator, characterized in that In order to expand the field of application, a sawtooth voltage generator, the second input of which is connected to the output of the delay line, the second local oscillator, the second mixer, the second input of which is connected to the output of the switch, the second intermediate frequency amplifier and signal processing, each of which contains a CRT and a series-connected frequency multiplier, a frequency divider, an amplitude detector connected to a vertical CRT electrode, is connected to the output of rator sawtooth voltage. Yu hch and OPM LFMN Tfm W Well LU # BUT/ wh Editor M. Tsitkina  Compiled by V. Novoselov Tehred M. Khodanich Proofreader Order 215 Circulation 535 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 her her and l with FIG. one t Subscription