Abstract: For detecting pulsatory interference in a sampled audio signal, the value of a given signal sample is compared with the values of previous as well as subsequent signal samples within a selected time window. If the given sample, multiplied by a selected attenuation factor, exceeds a certain percentage of all such samples, that identifies it as an interference pulse. It can then be replaced by an interpolated sample value derived from adjoining samples over a selected interval of the signal.

Abstract: A receiver comprising a multi-path detector which comprises a frequency noise peak detector, an AM-detector and a weighting circuit. When noise peaks and amplitude modulations occur in an antenna input signal selected by a diversity switch on account of a control signal of the weighting circuit one of a number of antennas is switched to. This switching is audible to an annoying degree. By inserting a threshold arrangement (31, 32) in the detector, by means of a low-pass filter and a rectifier circuit, an instantaneous threshold voltage is generated varying with the frequency swing of the modulating signal. With a large swing, corresponding with a large amplitude of the modulating signal, switching is audible to a less annoying degree. On the other hand, at moments when the modulating signal has a small amplitude, switching may take place more frequently and is less audible because of the small amplitude of the modulating signal.