SU1401423A1 - Pulsed radio signal delay device - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase noise immunity by eliminating interfering echoes and losses in terms of useful echo / noise. The device contains synchronizer 1, r-2 excitation radio pulses, phase shifters (EF) 3 and 4, resonance Synchronization systems (PC) 6 and 7 with working substance (PB) and block 8 of addition. Introduced PV 5. M. b. Both electronic and nuclear spin echo are used. In the latter case, RV M.b. ferrites, in which there are internal local magn. the floor In this case, the phase shifts of the signals supplied to the PC 7 and removed from its output are rotated by 90 °. coils included in this system, according to the Crimea, the corresponding signals are given. With electronic spin echo as PB, m. Samples of Y-irradiated quartz placed in a reflective resonator located in a constant inhomogeneous magn. field. The resonator has only one input, which is the output. The phase shifts of the input and output signals, as well as the addition of the output signals of PC 6 and 7 can be accomplished using a quadrature bridge, two developed arms are connected to the i-th and 2nd reflective resonators, and the third arms are fed exciting radio pulses , and in the 4th comes information. signal. 2 Il. - Output a $ (L from 4 to oo

Description

Log into LT

figure 1

The invention relates to radio shading and can be used in radar stations for control (Delays of received radio pulses under conditions of receiver noise.

The purpose of the invention is to increase the noise immunity by eliminating disturbing echoes and losses in terms of useful echo / noise.

FIG. 1 shows the structural electrical circuit of the device; in fig. 2 - timing diagrams for the operation of the device.

The delay device of the pulse radio signals contains a synchronizer 1, a generator of 2 excitation radio pulses, the first 3, the second 4 and the third 5 phase shifters, the first 6 and second 7 resonant systems with the working substance and the block 8 of addition.

The delay device of the impulse radio beacon operates as follows.

Synchronizer 1 receives a short sync pulse (figure 2, under the action of which synchronizer 1 produces a sequence of two or several (if necessary to generate several echo signals) short video pulses. Figure 2 shows a sequence of three video pulses on the output of synchronizer 1, which is necessary for two echo signals delayed respectively by a time t- and taj relative to the information signal (Fig. 2c), which is fed to the input of the first phase shifter 3 and the first resonant system 6 s pa After the arrival of the sync pulse (Fig. 2a), the time t, together with the duration of the information signal fc (Fig. 2c), must exceed 1 time of spin-spin relaxation T

working substance (t,

+ T-T,) ...

A sequence of video pulses arising at the output of synchronizer 1 (Fig. 26). is supplied to the input of the generator 2 of excitation radio pulses, at the output of which a corresponding sequence of radio pulses is formed, acting on the first resonant system; 6 with the working substance and through the third phase shifter 5, which rotates the phase by 90 °, entering

to the input of the second resonant system 7 with the working substance.

The information signal (Fig. 2c) through the first phase shifter 3, providing a phase shift of –90, acts on the second resonant system 7 with the working substance.

Under the action of a sequence of radio pulses of the excitation and information signal at the outputs of both identical resonant systems 6 and 7 with the working substance arise as useful echo signals, representing a delayed information signal and arising at times

t, + s, and t «2 + s, menus and interfering echoes (Fig. 2d). FIG. 2d shows the most intense interfering echo signals: a two-pulse echo from the interaction of the first excitation radio pulse and an information signal that occurs immediately after the information signal, and a two-pulse echo from pairwise interaction of the excitation radio pulses that occur at times of 2t and 2t 5 - (

The output signal of the first resonant system 6 with the working substance is fed to the input of the adding unit 8, the second input of which through the second phase shifter 4, performing a 90 ° phase shift, receives the output signal of the second resonant system 7 with the working substance.

Without loss of generality, we assume the initial phases of the exciting radio pulses and the information signal at the input of the first resonant system 6 with the working substance are zero. In this case, the initial phases of all signals (Fig. 2d) at the output of the first resonant system 6 with the working substance will also be zero. The initial phases of the output signals of the second resonant system 7 with the working substance can be determined through the phase spectra of the double-pulse echo

I ehch) -CH, () + 2qij (w) (1) and three-pulse echo

 to) -c, (co) + q) ,, (co) +

+), (2)

 1 A

g de (f (co). if 2.

and cf (w) - phase spectra of the first, second and third signals under the action of which this echo was formed. From (1) and (2), taking into account the phase shift introduced by the second phase shifter 4, one can find the initial phases of the signals arriving at the second input of the adding unit 8 (Fig. 2d)

The initial phases of the useful signals of the three-pulse echo are

H

POA

 -Vj + V, + V + F ,,

.V, + (p, 0%

(3)

. Where V, -90%

(- phase shift, performed by - the first 3, the second 4 and the third 5. phase spreaders.

The initial phase of the moving two-pulse echo from the interaction of the first exciting radio pulse and information signal is equal to

M-Meuj ,, -О, - 2ф, -К, -180

(BUT)

The initial phases of the moving two-pulse echo from pairwise interaction of the exciting radio pulses are

  -V, + 2.4 g if + (g 180 °.

(five)

(

Equalities (3) - (5) show that the interfering echoes from both resonant systems 6 and 7 with the working substance arrive at the inputs of the combining unit 8 in antiphase and, having been compensated, do not pass to the output while the useful echoes on They turn on the corresponding inputs of the addition unit 8 in phase and their output power increases (Fig. 2e).

The powerful excitation radio pulses that seep into the corresponding inputs of the addition unit 8 are folded anti-phase and do not fall on its output (Fig. 2e).

Yu

15

20

- 25 30

35

40

- 0 a

gg

3

It has been established that the level of interfering echoes at the output of the addition unit 8 is 20 decibels less than the level of the same signals at the output of each of the resonant systems 6 and 7 with the working substance while the level of the useful signal increases by 3 decibels.

In the proposed device, both electron and nuclear spin echo phenomena can be used. In the latter case, the working substance can serve as ferrites, in which there are internal local magnetic fields, which makes it possible not to use a bulky magnetic system. At the same time, the necessary phase shifts of the signals supplied to the second resonant system 7 with the working substance and the signals taken from its output are rotated 90 to one or the other side of the coils entering this system (not shown), which are fed to the corresponding signals.

When using the electron spin echo phenomenon, samples of J-irradiated quartz placed in a reflection resonator (not shown) in a constant non-uniform magnetic field can be used as a working substance. The reflective resonator has only one input, which is also an output at the same time. In this case, all the necessary phase shifts of the input and output signals, as well as the addition of the output signals of the two resonant systems 6 and 7 with the working medium can be accomplished using a quadrature bridge (for example, a waveguide slotted bridge), which are connected to two the first and second reflective resonators, the third shoulder serves the exciting radio pulses, and the fourth shoulder receives an information signal (not shown). At the same time, the useful echoes coming from both resonators 6 and 7 into the first two shoulders of the bridge are added to the third shoulder, and the available echoes add up to the fourth shoulder and not to the third shoulder of the bridge.

Claims (1)

Invention Formula A delay device for impulse radio signals containing a series-connected synchronizer, a generator of exciting radio-impulses. The first resonant system with the working substance and the addition unit, and the first phase shifter connected in series, the second resonant system with the working substance and the second phase shifter, the output of which is connected to the second input of the addition unit, while the first phase input The spatula is connected to the second input of the first resonant system with the working substance and is the input of the device, characterized in that, in order to increase the noise immunity by eliminating disturbing echoes and losses in respect of the useful echo / noise, a third phase shifter is inserted between the generator output of the excitation radio pulses and the second input of the second resonant system with the working substance.