Abstract: In a communications system using a synchronous digital data stream employing multiple-amplitude-level symbols, preamble acquisition and d.c. offset correction is achieved simultaneously by receiver averaging of sampled values in amplitude and in time to determine the average d.c. offset and the nominal transition boundaries between symbols. After symbol timing acquisition and d.c. offset acquisition, other circuitry is enabled for symbol tracking, and additional circuitry uses the acquired d.c. offset and symbol timing information to extract the data from the symbol stream. D.c. offset tracking involves subtracting the d.c. offset value from the output of an ADC representing the digitized baseband signal and then adjusting the d.c. offset value by a fraction of the error between the actual value and the expected value relative to the offset corrected signal. Symbol timing tracking is accomplished through examination of the d.c.