Method for reducing noise included in a stereo signal, stereo signal processing device and fm receiver using the method
AssigneeSemiconductor Ideas to the Market (ITOM) B.V.
InventorHerman Wouter Van Rumpt
Life of this patent
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Abstract
Method for reducing noise included in a stereo reproduction signal derived from a stereo input signal characterized by the steps of: *varying stereo channel separation of said stereo reproduction signal with frequency within the frequency range of the stereo input signal in accordance with the frequency response of a filter selectivity located around a center frequency to obtain a stereo channel separation peak value at said center frequency; *at a continuing increase of said noise, decreasing the bandwidth of said filter selectivity to a pre-determined non-zero bandwidth while maintaining the channel separation within the bandwidth of said filter selectivity substantially at said channel separation peak value.
Claims20
A method for reducing noise included in a stereo reproduction signal derived from a stereo input signal comprising:
- varying channel separation of the stereo reproduction signal with frequency within the frequency range of the stereo input signal in accordance with the frequency response of a filter selectivity located around a non-zero center frequency to obtain a channel separation peak value at the center frequency;
- obtaining a measure of the noise;
- and
- decreasing the bandwidth of the filter as the noise increases, the decreasing bandwidth being limited to a predetermined non-zero bandwidth.
A stereo signal processing device for reducing noise included in a stereo reproduction signal derived from a stereo input signal, including:
- first and second channels receiving respectively first and second signal components of the stereo input signal,
- at least one filter located around a non-zero center frequency and coupled to at least one of the first and second stereo channels, a channel separation of the stereo reproduction signal being defined by a frequency response of the filter, with a channel separation peak value at the center frequency, and
- an SNR detector that generates a bandwidth control signal that varies with an SNR of at least part of the stereo input signal, the bandwidth control signal decreasing the bandwidth of the filter as the SNR decreases, and vice versa, the decreasing bandwidth being limited to a predetermined non-zero value.
Dependencies are inferred from the claim text.