Abstract: A portable receiver receives information on a network of FM SCA transmitters. Each transmitter may have a different cell size. A handoff is performed when the portable receiver travels from the coverage area of one network transmitter to another network transmitter. Fluctuations in signal quality could result in several handoffs as the portable receiver travels. Excessive handoff operations potentially reduce the battery life of the portable receiver. The portable receiver performs channel scanning and locking on a priority basis that reduces the likelihood of additional handoffs. Priority basis is assigned to a transmitter based upon indicia including its coverage area causing the portable to prefer locking on to transmitters on the basis of both signal quality and channel priority.

Abstract: A method for tracking a received signal comprises the steps of setting (635) a counter (130) to a first value indicative of a first signal voltage, determining a center threshold of the received signal, and determining a number of center transitions of the received signal within a predetermined time period. The method further comprises the step of automatically decrementing (685, 695) the counter (130) to a second value indicative of a second signal voltage in response to expiration of a predetermined amount of time, wherein the second value differs from the first value by a predetermined amount determined by the number of center transitions of the received signal within the predetermined time period.

Abstract: A selective call receiver (106) receives a radio frequency signal having digital signals contained within symbols. The signal demodulated by the receiver (804) comprises a substantially constant DC offset voltage and an AC voltage (1810) indicative of the information contained within the symbols. A threshold level extraction circuit (808) which extracts the offset voltage is synchronously controlled (1840) providing for sampling of the received signal by the threshold level extraction circuit in substantially the center of each symbol.

Abstract: A radio communication device (100) for receiving a signal comprises tracking circuitry (115) for tracking the signal to acquire peak and valley values of the signal, a threshold detector (150) coupled to the tracking circuitry (115) for determining a center threshold of the signal, and an edge detector (180) coupled to the threshold detector (150) and the tracking circuitry (115) for determining a number of center transitions of the signal in a predetermined time period. The radio communication device (100) further comprises a rate controller (185) coupled to the edge detector (180) and the tracking circuitry (115) for receiving the number of center transitions and for adjusting an acquisition rate with which the peak and valley values are acquired in accordance with the number of center transitions.