Motorola Corporation

Daniel A Morera

David R Petreye

Carla J Maroun

Clinton C Powell, Ii

Mark L Oliboni

Mark L Servilio

A symbol detector (110) includes an analog-to-digital converter (115) for converting signal voltages to digital values and peak and valley counters (310, 315) for tracking the digital values to determine peak and valley values associated with high and low voltages of the signal. The symbol detector (110) further includes calculation circuitry (356) for calculating upper, lower, and center thresholds based on the peak and valley values and a decoder (125) for generating data symbols in accordance with the upper, lower, and center thresholds.

Radio communication device and method for generating threshold levels in

A symbol detector (110) for generating data symbols from a received signal having multiple signal voltages comprises an analog-to-digital converter (115) for converting the multiple signal voltages to digital values and peak and valley counters (310, 315) coupled to the analog-to-digital converter (115) for tracking the digital values to determine peak and valley values associated with high and low voltages, respectively, of the received signal. The symbol detector (110) further comprises calculation circuitry (120) coupled to the peak and valley counters (310, 315) for calculating upper, lower, and center thresholds in accordance with the peak and valley values and a decoder (125) coupled to the analog-to-digital converter (115) and the calculation circuitry (120) for generating the data symbols in accordance with the digital values and the upper, lower, and center thresholds.

Method and apparatus for generating threshold levels in a radio

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.

Method and apparatus for digitally tracking highs and lows of a signal

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.

Synchronized offset extraction in a data receiver

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.

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Boynton Beach, FL, United States of America

Daniel A Morera