Method for limiting radio noise, in particular in the fm band, by polynomial interpolation
AssigneesContinental Automotive France, Continental Automotive GmbH
InventorsChao Lin, Cyrille Potereau
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Abstract
A method for limiting impulse noise in a radio signal, in particular in the FM band, that is multiplexed and intended to be received by an FM receiver that is for example located on-board a vehicle. The method includes detecting impulse noise by way of a calculation of a score IND, for a sequence of successive samples of the demodulated radio signal FM MPX, while taking into the account, on the one hand, a capacity to detect a drop in the modulus of the ratio I/Q, which is dependent in particular on data derived from a sensor level, and, on the other hand, a capacity to detect high-frequency noise, which in particular depends on data derived from a sensor modulation.
Claims11
A method for limiting noise in a received radio signal,
- especially in the FM band, said received radio signal being multiplexed according to a quadrature amplitude modulation scheme, said modulated received radio signal comprising an in-phase component and a quadrature component, the received radio signal being demodulated in order to consist of a succession of samples, and said radio signal including a risk of impulse noise liable to degrade a returned radio signal, said method comprising:
- detecting a drop in the modulus of the ratio between the in-phase component and the quadrature component of the modulated received radio signal, depending on the average modulus over time of the modulated received radio signal;
- detecting high-frequency noise in the demodulated received radio signal, depending on a threshold, said threshold being determined dynamically depending on the modulation of the modulated received radio signal;
- calculating an impulse noise score, said impulse noise score being dependent on the detection carried out in the first step and on the high-frequency noise detection carried out in the second step;
- depending on the impulse noise score calculated, determining a number of samples, forming a sequence of samples to be substituted, between a last preserved non-noisy sample and a restart non-noisy sample, in the demodulated received radio signal;
- creating a sequence of substitution samples, by polynomial interpolation between the last preserved non-noisy sample and the restart non-noisy sample;
- and
- returning a modified demodulated radio signal corresponding to the demodulated received radio signal in which the sequence of samples to be substituted has been replaced by the sequence of substitution samples.
Dependencies are inferred from the claim text.