Patent ID: 8280328

Claim:
A sensor for detecting an incident RF signal having a carrier frequency, and for estimating said carrier frequency, the sensor comprising: (i) a plurality of filters, each allowing passage of signals over a different band of frequencies from the band of frequencies over which passage of signals is allowed by the others of the plurality of filters; and (ii) a plurality of detectors; wherein each filter is associated with at least one of the plurality of detectors, and said at least one detector is arranged in use to generate an output signal if the incident RF signal results in a signal in the band of frequencies passed by the filter with which the detector is associated; wherein generation of the output signal by the detector indicates in which of the frequency bands the incident RF signal has been detected; and wherein each of the plurality of filters has a bandpass width of more than 1.5 MHz such that, between arrival of the incident RF signal at the sensor and generation of the output signal indicating in which of the frequency bands the incident RF signal has been detected, there is a delay of not more than 1 microsecond.