RU2012109531A - METHOD FOR SPECTRAL SUPPRESSION OF IN-BAND INTERFERENCE AND NOISE - Google Patents

Abstract

A method of spectrally suppressing in-band interference and noise, including converting the frequency of the input signal down, digitizing the intermediate frequency signal, buffering the digitized samples of the signal, capturing a pseudorandom sequence code, generating a signal spectrum with the captured code — the frequency panorama, and partial correlation processing, including tracking the carrier with using phase-locked loop, characterized in that, instead of determining the parameters of in-band interference in the frequency pan for tuning ki interference filters, isolate the carrier frequency of the signal, filter it with a narrow-band filter mask in the frequency domain, which multiplies the filter mask by the spectral power density of interference and noise in the operating frequency range of the receiver, performs an inverse fast Fourier transform of the filtered spectrum with suppressed in-band interference and noise, receive a filtered carrier in the time domain and carry out phase-locked loop operations, suppression of in-band interference and The s are performed in 2 stages - initialization and refinement, in each of them a filter mask is formed in the form of an exponential part of the normal probability density, without a factor, taking it equal to where ƒ is the carrier estimate value extracted from the frequency panorama, σ is at the initialization stage for an arbitrary moment the inclusion of navigation equipment for both marine and aviation consumers is taken to be 2.67 Hz, after the initialization phase is completed, the carrier frequency estimate ƒand σ is refined using phase-locked loop, these updated

Claims (1)

A method of spectrally suppressing in-band interference and noise, including converting the frequency of the input signal down, digitizing the intermediate frequency signal, buffering the digitized samples of the signal, capturing a pseudorandom sequence code, generating a signal spectrum with the captured code — the frequency panorama, and partial correlation processing, including tracking the carrier with using phase-locked loop, characterized in that, instead of determining the parameters of in-band interference in the frequency pan for tuning ki noise-suppressing filters, isolate the carrier frequency of the signal, filter it with a narrow-band filter mask in the frequency domain by multiplying the filter mask by the spectral density of the interference power and noise in the operating frequency range of the receiver, conduct an inverse fast Fourier transform of the filtered spectrum with suppressed in-band interference and noise, receive a filtered carrier in the time domain and carry out phase-locked loop operations, suppression of in-band interference and s operate in two phases - initialization and updating, in each of which a filter mask is formed in a part of the normal exponential probability density, without the factor $$\raisebox{1ex}{$\mathrm{one}$}\!\left/ \!\raisebox{-1ex}{$\sigma $}\right.\sqrt{2\pi }$$

taking it equal $$F(ƒ)=\exp \left[-\frac{\mathrm{one}}{2}{\left(\frac{ƒ-ƒ{}_0}{\sigma }\right)}^2\right],$$

where ƒ ₀ is the value of the carrier estimate extracted from the frequency panorama, σ - at the initialization stage for an arbitrary moment of switching on the navigation equipment for both marine and aviation consumers, it is taken to be 2.67 Hz, after the initialization stage is completed, the carrier frequency estimate ƒ ₀ and σ are refined using phase-locked loop, these updated values are used to generate filter masks when processing subsequent files of buffered signals, to remove the phase manipulation of the carrier with a pseudo-random code, instead of squaring the signal into a square, the amplitude spectrum of the signal is formed, for example Imer square root of the power spectrum, i.e. frequency panorama, the input signal is manipulated in phase by a meander with an integer number of periods per period of the code clock frequency.