Service detection circuit and method

摘要

A radiotelephone (121) employs a service detection circuit (125) comprising at least one chip-rate detector (109) that measures the energy of the autocorrelation of a received composite CDMA signal and employs a different time delay for each measurement of the energy. A threshold detection circuit (127) combines the measured energies and determines that service is available if the combined energies exceeds a threshold, and determines service is unavailable otherwise. The chip-rate detectors (109) can be coupled in parallel to provide simultaneous measurements of the energy of the autocorrelation of the received composite CDMA signal, or a single chip-rate detector (109) can serially measure the energy of the autocorrelation of the received composite CDMA signal.