James H Webster

US Patent:

57990433, Aug 25, 1998

Filed:

Jun 2, 1997

Appl. No.:

8/867498

Inventors:

James Rodney Webster - Boynton Beach FL
Clinton C. Powell - Lake Worth FL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04L 2534

US Classification:

375286

Abstract:

A selective call unit (800) comprising a receiver (100) and a processor (810) is used for decoding a 2-level radio signal. The processor (810) is adapted to convert in-phase and quadrature signals generated by the receiver (100) to a sequence of state transitions representative of the plurality of symbols. For each symbol in the plurality of symbols, the processor (810) counts the sequence of state transitions during a symbol period, and compares the recorded count to a predetermined threshold, thereby generating a comparison result. The processor (810) then calculates a bit decision threshold level based on an average of the comparison result for each symbol in the plurality of symbols. For each symbol in a plurality of subsequent symbols, the processor (810) then compares the bit decision threshold level to the sequence of state transitions counted during a symbol period to decode a digital logic level therefrom.