Carrier and Clock Recovery for 8 PSK Synchronous Demodulation

Synchronous demodulation of Phase-shift-keyed transmissions requires the recovery of carrier and clock timing signals. Envelope detection of the 70 MHz IF signal is used to recover clock, and baseband processing is used to recover carrier for an 8 PSK digital radio with a data rate of 90 Mbits/s in the 11 GHz band. A sequential phase detector is used in a high noise application. Two versions of the carrier recovery circuit are presented. The first one employs hot carrier diode quads to form a compound Costas loop. The second one employs ECL exclusive-OR gates. Emphasis is placed on providing high performance while conserving energy, space, and manufacturing cost.