SU1160570A1 - Versions of correlator for processing frequency-modulated signal - Google Patents

Abstract

1. A correlator for processing a frequency-modulated signal, comprising a reference oscillator, a first frequency converter, N overmultipliers, N weight amplifiers, and a series-connected adder with N inputs and an integrator whose output is the output of the correlator for processing the frequency-modulated signal, the first frequency converter is connected to the first input of the first multiplier, and the outputs of the N multipliers are connected through the appropriate weighting terminals to the inputs of the adder with N inputs This is due to the fact that, in order to increase the efficiency of side-bbtx suppression of output lobes, a reference frequency synthesizer with N outputs and (N-1) frequency converters has been introduced into it, with outputs (N- 1) the entered frequency converters are connected to the first inputs of the corresponding multipliers, the output of the reference oscillator is connected to the second inputs of N multipliers, and the N outputs of the reference frequency synthesizer are connected to the second inputs of the corresponding S frequency converters, the combined first inputs of which x are input to the correlator processing chastotnomodulirovannogo signal. 2. A correlator for processing a frequency modulated signal. Contains a reference oscillator, CO first frequency converter, N multipliers, N weight amplifiers with: and a series-connected adder with N input and an integrator whose output is in the output of the correlator for processing the frequency-modulated signal, and the output about: of the oscillations is connected to the first input of the first frequency converter, and the outputs of the N multipliers are connected through suitable-weight signals to the inputs of the adder with the H inputs, characterized in that objectively suppress lateral O. Lenestkov of a vykodny signal, in; it has a synthesizer reference frequency with N outputs and (I-1) frequency converters, the combined first go-N transformers are the input of the correlator for processing the frequency-mode of the horned signal, the output of the reference oscillator is connected to the primary inputs

Description

(N-1) entered frequency converters, and the N outputs of the reference synthesizer are connected to the second inputs of the corresponding N frequency converters, the outputs of which are connected to the second inputs of the corresponding N 1160570 multipliers.

The invention relates to radio engineering and can be used in receiving devices of frequency modulated signals. A frequency modulated receiver is known (FMH signals with side-lobe suppression of responses, which contains additional channels for detection of the detectors and an adder for the responses of all the detector channels with weight amplifiers at the inputs 1. However, this device is not very effective when the responses of individual channels have large and slowly falling side lobes, due to pulsations of the amplitude of the spectrum of the signal, coming to zero level. A correlator is known for processing the frequency-modulated signal, with holding the reference oscillator, the first frequency converter, N multipliers, N weight amplifiers and a series-connected adder with N inputs and an integrator whose output is the output of the correlator for processing the FM signal, the output of the first frequency converter connected to the first one multiplier, and the N outputs of the multipliers are dinene through appropriate weight amplifiers with inputs of an adder with N inputs 2, A correlator is also known for processing a frequency-modulated signal containing a generator reference oscillations, a first frequency converter, N multipliers, N weight amplifiers and a series-connected adder with N inputs and an integrator whose code is the output of the correlator for processing the FM signal, with the reference oscillator connected to the first input of the first frequency converter , and the outputs of the N multipliers are connected through the corresponding weight amplifiers with the inputs of the adder with N inputs 2. However, the known correlators have a low efficiency of suppressing the side lobes of the input signal. The purpose of the invention is to increase the efficiency of suppression of the side lobes of the output signal. To achieve this goal, the correlator is a processor for processing the frequency-modulated signal in the first embodiment, comprising a reference oscillator., A first frequency converter, N multipliers, N weight amplifiers, and a series-connected adder with N inputs if an integrator whose output is the output of the correlator to process the frequency-modulated signal, the jipH4eM output of the first frequency converter is connected to the first input of the first multiplier, and the outputs of the N multipliers are connected through appropriate weighting amplifiers The drivers have inputs of an adder with N inputs, a reference frequency synthesizer with N outputs and (N-1) frequency converters are entered, the outputs (N-1) of entered frequency converters are connected to the first inputs of the corresponding multipliers, the output oscillator of the reference oscillations is connected to the second inputs N multipliers, and the N outputs of the reference synthesizer are connected to the second inputs of the corresponding N frequency converters, the combined first inputs of which are the input of the correlator for processing the frequency-modulated signal. 3 V correlator for processing the frequency modulated signal according to the second variant, containing the generator of the oscillation oscillator, the first frequency converter, N multipliers, N weight amplifiers, and successively connected adder with N inputs and the integrator whose output is a correlator output for processing the frequency-modulated signal, the code of the reference oscillator is connected to the first input of the first frequency converter, and the outputs of the N multipliers are connected through the appropriate weighting amplifiers from the input An adder with N inputs, a reference synthesizer with N outputs and (N-1) frequency converters are entered, the combined first N inputs of the hubs are a correlator input for processing the frequency-modulated signal, the output of the reference oscillator is connected to the first inputs (N -1) entered frequency converters, aN outputs of the reference synthesizer are connected to the second inputs of the corresponding N frequency converters, the outputs of which are connected to the second inputs of the corresponding N multipliers. FIG. 1 shows a structural electrical correlator circuit for processing a frequency-modulated signal according to the first embodiment; in fig. 2 - the same, according to the second option; in fig. 3 - Correlation tori response amplitude (Fig. 1 and 2) contain N multipliers 1, N weight amplifiers 2, adder 3 with N inputs integrator 4, N frequency converters 5, oscillator 6 reference oscillations and synthesizer 7 reference frequencies Correlator in the first variant works in the following way. A narrowband FM signal of a given type of modulation simultaneously arrives at the inputs of N frequency converters 5, the outputs of which receive different relative shifts of a given magnitude and a common shift for all channels leading to the carrier frequency of the signal with a zero relative shift to the carrier frequency of the reference FM-to-oscillation “At the same time, the initial phases of all converted oscillations are the same, which is achieved by precision and identity of the characteristics of all converters 5 or by the formation of oscillations One synthesizer 7 in one of the total oscillator. Synchronization of the synthesizer 7 with the generator 6 reference oscillations is allowed. From the outputs of the converters 5, the converted signals are fed to the signal inputs of the respective multipliers 1, to the other inputs of which from the output of the generator 6 in parallel receives a narrowband FM reference oscillation of a given type of modulation. The multipliers 1 operate in the reference frequency band. From their outputs, the product of the oscillations is fed to the inputs of the respective weight amplifiers 2, the gain factors of which are constant in the frequency band of the envelope of the reference oscillation, and are proportional to the given weights of the channels. The negative sign of the weight is provided by either the phase inverter circuit. my amplifier, or reverse switching its output pins. From the outputs of the weight amplifiers 2, the product of oscillations is fed to the corresponding inputs of the adder 3 with N inputs, also operating in the frequency band of the reference oscillation envelope. The total oscillation from its output goes to the input of integrator 4, the output of which is the response of the correlator. The integration time depends on the requirements of a specific task, but there can be no less than one repetition period of the signal. The value of the response depends on the relative signal lag and reference oscillation. This dependence in the case of a single signal has the form of a high-frequency pulse, the amplitude has the main and side lobes of a given shape. The filling frequency is equal to the carrier frequency of the reference oscillation. The response bending is highlighted during subsequent non-linear processing by the detector (HJ Fig. 1 is not shown). According to the second variant (Fig. 2), the correlator works as follows. A narrow-band FM signal of a given type of modulation simultaneously arrives at the signal inputs of the N multipliers 1. The other inputs of multipliers 1 from the generator 6 of the reference oscillations receive narrow-band reference. FM oscillation of a given type of modulation.

Pre-passed through appropriately frequency converters 5, in which they receive different relative frequencies of a given magnitude and a common shift for all channels leading to the carrier frequency of the reference oscillation in the channel with zero relative shift to the value of the carrier frequency of the signal. At the same time, the initial phases of all converter reference oscillations are the same, which is achieved by the precision and identity of all frequency converters 5 or by oscillation of the local oscillators in one synthesizer 7 from the common master oscillator. Synchronization of the synthesizer 7 with the oscillator b of the reference oscillations is allowed. The multipliers 1 operate in the signal's frequency band. From their outputs, the oscillations arrive at the inputs of the respective weight amplifiers 2, the gain factors of which are constant in the frequency band of the signal's envelope and are proportional to the given weights of the channels. The negative sign of the weight is provided either by the phase-inverter amplifier circuit, or by reverse switching its output pins. From the outputs of the weight amplifiers 2, the oscillations arrive at the corresponding inputs of the adder 3 with N inputs, also operating in the frequency band of the envelope signal. The totalizer oscillation from its output enters the input of integrator 4, the output of which is the response of the correlator. The integration time depends on the requirements of a specific task, but there can be no less than one repetition period of the signal. The value of the correlator response depends on the relative delay of the signal and the reference oscillation. In the case of a single signal, this dependence has the form of a high-frequency pulse, the amplitude of which has the main and side lobes of a given shape. The fill rate is equal to the carrier frequency of the signal. The response envelope (amhmtmud) is highlighted during subsequent non-linear processing by the detector (not shown in Fig. 2). In the practical implementation of the proposed correlator, it is possible in both cases to include integrators between the outputs of the multipliers and the adder j

The circuits consisting of a multiplier with a corresponding frequency converter, an integrator and a reference oscillation can be replaced with an equivalent matched filter, whose central frequency is respectively tuned from the center frequency of the signal.

Example. The FM signal is sinusoidally modulated with the modulation index m and the modulation (repetition) frequency F. The reference oscillation has the same modulation law. The envelope of the response of the optimal correlator has the form of the Bessel function of the first kind of zero order jj, (21Г taFx), where x is the relative delay of the signal and the reference oscillation. This response has anomalous (large and slowly falling) side lobes (Fig. 3, curve C4), due to deep pulsations of the amplitude of the frequency spectrum of the signal. The shape of the response envelope of the correlator of the torus with the suppression of side lobes (according to any of the proposed options) is given in the form

yxC), t, P «) i7 Lz {21GMYah),

where L - l mbda functions of the i-ro order (i 1,3).

This envelope has side lobes less than 2% of the main lobe (Fig. 3, curve CG IY expression can be represented by a weighted sum of mutual functions of correlation of signals with spectra shifted relative to each other - an approximating polynomial Amplitude of mutual correlation functions when shifting spectra by the value of kF in this case are

W {- f3 21ittiPx),

where J., is a Beséel function of the first kind of order (k 0,1,2 ...). Approximate polynomial

))

describes a given envelope if the values of the weighting coefficients are HMSUo 1; Wi. -1.35; W. 0.42; Wg -0.07, a for all other k - W | O. Thus, given

the suppression of the lateral lobes of the correlator response occurs with the following values of the parameters: the number of channels — 4; frequency shifts in the channel. Input Figure 1 Wmd FtL2.t

lakh (including channel with zero offset): 0.2 F, 4F / 6F; corresponding channel weights: 1; -1.35; +0.42 | -0.07. Vyv9 U1 Uf DP P If gtr .fi tf if LLJ

Claims (2)

1. A correlator for processing a frequency-modulated signal, comprising a reference oscillator, a first frequency converter, N multipliers, N weight amplifiers and a series-connected adder with N inputs and an integrator, the output of which is the output of a correlator for processing a frequency-modulated signal, the output of the first frequency converter connected to the first input of the first multiplier, and the outputs of N multipliers are connected through the corresponding weight amplifiers with the inputs of the adder with N inputs, t and h The fact is that, in order to increase the efficiency of suppressing the side lobes of the output signal, a reference frequency synthesizer with N outputs and (N-1) frequency converters is introduced into it, and the outputs (N-1) of the introduced frequency converters are connected to the first the inputs of the respective multipliers, the output of the reference oscillator is connected to the second inputs of the N multipliers, and the N outputs of the reference frequency synthesizer are connected to the second inputs of the corresponding N frequency converters, the combined περε whose inputs are the input ohm: correlator for processing a frequency-modulated signal. 2. A correlator for processing a frequency-modulated signal, containing a reference oscillator, a first frequency converter, N multipliers, N weight amplifiers and a series-connected adder with N inputs and an integrator, the output of which is the output of a correlator for processing a frequency-modulated signal, moreover, the output of the reference oscillator is connected to the first input of the first frequency converter, and the outputs of N multipliers are connected through the corresponding weight amplifiers to the inputs of the adder from the K input and, characterized in that, in order to increase the efficiency of suppressing the side lobes of the output signal, a reference frequency synthesizer with N outputs and (Ν-1) frequency converters is introduced into it, and the combined first inputs of N multipliers are the input of the correlator for: frequency-modulated processing signal, the output of the reference oscillation generator is connected to the first inputs (N-1) of the input frequency converters, and N outputs of the reference frequency synthesizer are connected to the second inputs of the corresponding N frequency converters, the outputs of which are connected to the second inputs of the corresponding N multipliers.