Methods for processing and analyzing a signal, and devices implementing such methods
OwnerYves Rezainventor
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Abstract
A method for processing an initial signal includes a useful signal and added noise, which comprises a step of frequency selective analysis providing starting from initial signal a plurality of wideband analysis signals corresponding to one of the analysed frequencies, and comprising the following actions: zero or more complex frequency translations, one or more undersampling operations, computation of the instantaneous Amplitude, of the instantaneous Phase, and of the instantaneous Frequency of the wideband analysis signals. This information then allow to detect modulations of signals included in high levels of noise and to detect with a good probability the presence of a signal in a high level of noise.
Claims22
Method for processing an initial signal by the means of a plurality of analysed frequencies in said initial signal, comprising a useful signal comprising a sum of elementary signals, representative of a wave that propagates in a physical medium, to which added noise can be added,
- said method being implemented on a sequence of samples, sampled at a constant sampling frequency, obtained from an initial signal,
- said method comprising a frequency selective analysis step, providing starting from the initial signal a plurality of wideband analysis signals, each wideband analysis signals corresponding to one of the analysed frequencies, said step comprising the following sub-steps:
- AS1) a series of undersampling operations, comprising each a lowpass or bandpass frequency filtering, and a corresponding suppression of samples;
- AS2) at least one lowpass or bandpass frequency filtering operation not followed by a corresponding suppression of samples;
- and
- AS3) zero or more complex frequency translation operation which brings the analysed frequency to a first operating frequency adapted to compute instantaneous Amplitude and to second operating frequency adapted to compute Instantaneous Phase and Instantaneous Frequency of analysis signal.
Analysis method of an initial signal using a plurality of analysed frequencies in the said initial signal, comprising a useful signal comprising a sum of elementary signals, representative of a wave that propagates in a physical medium, to which added noise can be added, in order to provide parameters indicating presence and a description of the modulations of each of the analysed frequencies of the plurality of analysed frequencies,
- said method being implemented on a sequence of samples, sampled at a constant sampling frequency, obtained from an initial signal,
- said method comprising following sequence of steps:
- 1.1) A frequency selective analysis step providing starting from the initial signal a plurality of wideband analysis signals, each wideband analysis signals corresponding to one of the analysed frequencies,
- 1.2) A plurality of operations of extraction of parameters of the wideband analysis signals for each sample of the plurality of wideband analysis signals, these parameters comprising at least the following signals:
- a) Instantaneous Amplitude of the wideband analysis signal,
- b) Instantaneous Phase of the wideband analysis signal,
- 1.3) A plurality of operations for estimation of the modulation of the signal which each one determine for each sample of the plurality of wideband analysis signals, and for a duration of samples of wideband analysis signal the following indicator:
- a) an indicator of non-significant signal, which is false by default and true if at least one of the three conditions is satisfied:
- a.1) if the Instantaneous Amplitude of the wideband analysis signal is, during the observation duration of samples of the wideband analysis signal an average value lower than a first limit defined in advance or an instantaneous value lower than a second limit defined in advance;
- a.2) if at least three observed indicators, directly comparable for both possible values and speed of variation, show a bad temporal concordance regarding the apparition of significant events, such as maximum, minimum or fast transitions;
- and
- a.3) if at least an indicator of useful signal presence and signal to noise ratio estimation indicates a signal absence or a too important noise;
- b) and at least two other indicators, directly comparable for both possible values and speed of variation, such as:
- ic.1) at least one of the directly comparable indicators comes from instantaneous amplitude information, and
- ic.2) at least one of the directly comparable indicators comes from instantaneous phase or frequency information.
Device for analysis of a signal and for detecting a plurality of analysed frequencies within said initial signal possibly significantly noisy, sampled at a constant sampling frequency, said device comprising a computing platform receiving an initial signal representative of a wave that propagates in a physical medium, and being adapted to implement one of the previously mentioned methods.
Dependencies are inferred from the claim text.