SU1647460A1 - Device for phasing microwave plumbing - Google Patents

Abstract

The invention relates to a radio-death technique. The purpose of the invention is to simplify the device and increase its accuracy. The device contains a oscillating frequency generator 1, a divider 2, phased microwave trains 3, segments 4 transmission lines, probes 5, amplitude detectors b, selective amplifiers 7, modulating reflectors 8, generator 9 modulation frequencies, synchronous detectors 10, drivers 11 short pulses, an adder 12 and an oscillographic indicator 13. In the device for phasing a microwave tramt 3, the comparison is made at a number of frequency points, But since FSK and y101 1 are long microwave paths 3 that contain wavelength grids but a lot. The device allows simultaneous phase switching .-, h v i-rznnyh phasing ambiguity of several microwave paths 3, the entrance, which can be separated over large distances. 1 il. {-, J

Description

The invention relates to radio measurement technology and can be used in radar, radio navigation and radio astronomy for phasing long microwave paths connecting spaced receivers (or transmitters) with spaced transmitters (or receivers).

The aim of the invention is to improve the accuracy and simplification.

The drawing shows a structural electrical diagram of a device for phasing microwave paths.

The device comprises a oscillating frequency generator 1, a microwave divider 2, phased microwave paths 3, segments 4 of the transmission line, probes 5, amplitude detectors 5, selective amplifiers Ί, modulating reflectors 8, a modulation frequency generator 9, synchronous detectors 10, short pulse shapers 11 , adder 12 and oscilloscope indicator 13.

The device operates as follows.

The linear frequency modulation signal generated by the generator 1 is divided by a divider 2 into η channels according to the number of phased microwave paths 3, passes through them and is reflected by a modulating reflector 8, which is an O-P phase modulator. At the point where the probe 5 is turned on, there is a falling superposition in the transmission line and reflected waves, included at the output of the probe 5, the amplitude detector 6 detects the total signal, which for the first half-period of modulation _{у7 0Т} p = 0 has the form

Ui = Kd) and _P ad1 ² (1 + + 2 р cos φ _κ ) where = ^ Ц =! ΓΙθη ² l '-' pad |

I Chotr I - amplitude of the reflected wave;

I Unafll - amplitude of the incident wave;

<Pk is the phase shift between the incident and reflected waves;

| G | - module reflectance of the modulating diffuser 8;

Op ~ loss of phased microwave path 3;

Cd is the gain of the amplitude detector 6.

For the second modulation half-time Ιοτρ = l, the total signal has the form

U2 = Kd | and _PZ d | ² (1 + -2p cos ^ k).

Selective amplifier 7 isolates the variable component of the modulation frequency F _M amplified by a factor of Ku proportional to the difference U1-U2, which is equal to

U3 “4KuKd | TspadG p cos </ \ cos2tt F _M t.

The output voltage of the synchronous detector 10 when applying to its reference input a rectangular voltage sign (cos2 π F _M t) is

W - Kci Ku Cd jCad | ² pCOS <f> K ~ ⁼ KC1 Ku Cd) Unafl (P COS [2π2 forn (f / fcp)}, where Kc 1 is the transfer coefficient of the synchronous detector;

foTH ⁼ G / Yao;

G is the electric length of the phased microwave path 3;

Lo ~ c / fcp;

fcp is the average frequency of the scanning range of the generator 1;

f-current frequency of the microwave signal.

When the frequency f changes, the voltage U changes according to the law of cosine. Shaper 11 at moments corresponding to the transitions of voltage U4 through zero l2 Gotn ((/ (cf) ⁼ n l, n = 0, 1, .... generates short pulses, which are summed in adder 12 and fed to the oscilloscope indicator 13. In this case the polarity of the short pulses generated by the shaper 11 is determined by the direction of the transition of Щ through zero (for example, when switching from a positive voltage to a negative positive voltage, a negative short video pulse), and the amplitude is the number of the phased microwave path 3.

To ensure the phasing of the microwave paths, it is thus necessary to adjust the tuning lengths of the microwave paths 3 included in the phased microwave paths 3 so that the short video pulses of the various microwave paths coincide on the screen of the oscilloscope indicator 13.

To eliminate the ambiguity of phasing, the coincidence of short video pulses in the entire range of the scanning frequency of the LFM microwave generator is necessary.

For example, if f ₀ ™ = 100, then during frequency tuning ± 2.5% - about 40 short video pulses and all these video pulses should coincide. If two microwave paths with Rotn = 200 differ from each other by 10, then the difference in frequencies f ¹ and f ¹¹ at which short video pulses are formed is 0.07%.

If a general scan in the 5% band is carried out in 1 s, then 0.07% scans for about 10 ms. Such a large interval is easy to fix. Thus, in a device for phasing microwave paths, comparison is carried out only at a number of frequency points. But since long microwave paths are phased in, in which hundreds of wavelengths fit, then there are a lot of such comparison points.

The device for phasing microwave paths allows you to simultaneously phase and eliminate the ambiguity of the phasing of several microwave paths, the inputs of these paths can be spaced apart over large distances. The absence of high-precision graduated connectors and the possibility of using conventional coaxial cables reduces the measurement time by more than 10 times. The error in phasing of microwave paths with VSWR up to 1.3-1.4 does not exceed ± 3 °.

Claims (1)

Claim A device for phasing microwave paths containing a serially connected oscillating frequency generator and a divider, serially connected amplitude detector and a selective amplifier, as well as a modulation frequency generator connected to the control inputs of modulating reflectors connected to the output of each of the η phased microwave paths, and an oscillographic indicator, the sweep input of which is connected to the control output of the oscillating frequency generator, characterized in that, in order to simplify and improve accuracy, the input q of each microwave path is connected to the corresponding output of the divider through the introduction of a series-connected probe and a segment of the transmission line, η-l amplitude detectors and selective amplifiers 10, η synchronous detectors are introduced, the reference input of each of which is connected to the output of the modulation frequency generator, signal ·: the input - with the output of the corresponding selective amplifier, 15 and the output through each of the η introduced shapers of short pulses with different amplitudes for each phased microwave path - with the corresponding input REFERENCE adder pod20 which keys output to the signal input of the oscillographic display, wherein the output of each probe via an amplitude detector connected to the corresponding input of the selective amplifier.