SU1177766A1 - Discriminator - Google Patents

Abstract

A DISCRIMINATOR containing the first and second channels, each of which contains a series-connected adjustable amplifier, a filter mutually orthogonal to the filter of the other channel, and a matching stage, with the channel outputs connected to the first and second inputs of the first multiplier, the output of which is connected to the input of the first integrator the output of which is connected to the output bus, successively connected to the third filter, the input of which is connected to the output of the adjustable amplifier of the first channel, the third A cascade and a second multiplier, the second input of which is connected to the output of the second channel, and the second integrator, the output of which is connected to the control inputs of adjustable amplifiers of the first and second channels, the inputs of which are connected respectively to the first and second input buses, characterized in that to expand the capture band by increasing the range of time shifts determined by the discriminator, a module for selecting a signal module was inserted into it, a non-linear converter and an adder were inserted, and the inputs of the block were audio modulation and the nonlinear transformer are respectively connected to the outputs of the first and second multipliers, and outputs respectively connected to first and second inputs of the adder, | whose third input is connected to the reference voltage source, and the calculation is connected to the second integrator input.

Description

The invention relates to radio engineering and can be used in automatic tracking systems for measuring the relative time shifts of two arbitrary waveforms. The aim of the invention is to expand the discriminator's capture bandwidth by increasing the range of time-shifted input signals determined by the device. FIG. 1 shows a structural discriminator; in fig. 2 form of discriminatory characteristics. The discriminator contains the first and second channels 1 and 2, each of which contains serially connected adjustable amplifiers 3 and 4, linear mutually orthogonal filters 5 and 6, and matching stages 7 and 8, respectively. In addition, the discriminator contains the first multiplier 9, the first integrator 10, the output of which is connected to the output bus 11, the third linear filter 12, the third matching stage 13, the second multiplier 1A, the second integrator 15, the first and second input buses 16 and 17 connected to inputs, respectively, adjustable amplifiers 3 and 4, block 18 of the selection of the signal module, nonlinear converter 19, adder 20 and source 21 of the reference voltage. The outputs of the first and second matching stages 7 and 8 are connected, respectively, with the first and BTopbiM inputs of the first multiplier 9, the output of which is connected to the input of the first integrator 10 and through the block 18 to the first input of the adder 20. The output of the first adjustable amplifier 3 through the third connected linear filter 12 and the matching helmet 13 is connected to the first input of the second multiplier, 14, the second input of which is connected to the output of the second matching cascade 8, and the output through the non-linear converter 19 to the second input of the adder 20, the third input of which is connected to the source 21, h. output via the second integrator 15 with control inputs of adjustable amplifiers 3 and 4. The gain of adjustable amplifiers 3 and 4 is proportional to the voltage Uppr at their control inputs. Filters 5 and 6 are mutually orthogonal. Filter 12 is similar to filter 6. Nonlinear converter 19 has a transmission coefficient of 1 O and l 0.5 dL and O, where and is the output signal of the second multiplier 14. The discriminator works as follows. Let the reference (f and current f signals with mutual relative shift f A coscuCt + t), LgCosut; arrive at the input buses 16 and 17 of the discriminator; . and And the amplitudes of the current and reference signals, respectively; T - time shift between the current and reference signals. After passing through amplifiers 3 and 4 and mutually orthogonal filters 5 and 6, having transfer functions Tr and и and ----, signals arrive at T + ip 1 Jp at the inputs of the first multiplier, U. The output signal of multiplier 9, Uj is smoothed by the first integrator 10 At the output of the integrator 10, a signal is generated that is proportional to the shift of the inter-control center Vg VT. This signal determines the discriminatory discriminator characteristic (HF). At the same time, the signals from the outputs of amplifiers 3 and 4 through filters 12 and 6, which have transfer functions, are fed to the inputs of the second multiplier 14. At the same time, at the output of the integrator 15, a signal is generated that is proportional to the derivative of the shift from the DX discriminator. The value of this signal is proportional to the slope of the HF. When this signal is applied to the control input of the adjustable amplifier 4, the input voltage of the second multiplier 14 is stabilized due to the control of its AGC circuit. This ensures the stabilization of the HH over the steepness. Determine the DF from the shift, taking into account the stabilizing effect of the AGC along the slope. The signals at the outputs of multipliers 9 and 14 can be represented by the following mathematical expressions: Jf2 and ,,). ("Jt + 4 arctg-j) cos (Lot arctg-j;)

   - (t + + i) G + 2arctg); (1)

Ug Uperf s fГ ° + arctg -) cos (u) t + tou - arctgu) t)

 | --F gt1: g - - i - arctgUt - arctg-) + cos (2iot +.

+ L0t + arctg- - arctguJT), (2)

. where uppj. -the value of the voltage at the output of the integrator 15.

 The effect of AGC on the slope reduces to the fact that the voltage at the output of the integrator 15 in a steady state, on average during the processing time T

(TD -;), should be equal to zero, i.e. should be fair expression ™. (pUi4 + U / I / / E) dt Oh, (3

Where. - the transfer coefficient of the nonlinear converter. (/ 3 1 with and O-i /,

 0.5 at - 0); оС signal weighting factor of the block 18 in the module section.

After integrating over time t expression (3) with the substitution of Hjij into it. and Ug from expressions (1) and (2) obtain the relationship between the reference voltage E and the output signals of the multipliers in the following mode, | g s / t2

ET - f- f; - ;, T, cpsu.

,, A,., | 3in.t ,. -(four)

Integration over time t of expression (2) for Ug leads to the expression

for discriminatory characterization of D (Zt) in a non-stabilized discriminator

AjArU P «r uiT

T.sinoJu

ten

2

15)

Substituting in (5) the value of Uper from (4), we find the discriminatory characteristic in the stabilized discriminator depending on the parameters of the AGC loop by the slope in the following form

nsl-TosiHifll (f,)

 , 1 (). LoV + - (sinu) l The expression for the steepness of the discriminatory characteristic can be obtained as; derivative with respect to-C from the expression (6).

When Г О we have 0 (0) - | -.

/ at

Near zero deviations, the DF does not depend on the amplitude and on the frequency of the input harmonic signal.

The discriminatory characteristic for the known discriminator is obtained from the expression (6) at ° C and / 5 1

. D ET o | guL5. (7)

The expressions (6) and (7) in Fig. 2 show characteristics, a comparative analysis of which allows us to conclude that the introduction of additional units (nonlinear converter 19, module 18 allocation module and adder 20) into the AGC circuit is approximately extends the capture band twice, as the range of measurable time shifts increases, and the linearity of the discriminatory response is also improved. The optimal values of the coefficient of linearity are in the range of 1-2.0.

,

Claims (1)

A DISCRIMINATOR comprising first and second channels, each of which contains a series-connected adjustable amplifier, a filter mutually orthogonal with the filter of another channel, and a matching stage, the channel outputs being connected respectively to the first and second inputs of the first multiplier, the output of which is connected to the input of the first integrator the output of which is connected to the output bus, a third filter is connected in series, the input of which is connected to the output of the adjustable amplifier of the first. channel, the third matching stage and the second multiplier, the second input of which is connected to the output of the second channel, and a second integrator, the output of which is connected to the 'control inputs of the adjustable amplifiers of the first and second channels, the inputs of which are connected respectively to the first and second input buses, characterized in that, in order to expand the capture band by increasing the range of time shifts determined by the discriminator, a signal module selection unit, a non-linear converter and an adder are introduced into it, while the inputs Lok allocation module and nonlinear transformer are respectively connected to the outputs of the first and second multipliers, and outputs respectively connected to first and second inputs of the adder, a third input coupled to a source of reference voltage, and an output - to an input of the second integrator. SU _n „1177766