High-speed QPSK/OQPSK burst modem VLSIC

High speed QPSK/OQPSK full digital burst modem VLSICs are developed. The demodulator VLSIC employs a reverse-modulation scheme for carrier recovery and an interpolation scheme coupled with a pulse shape filter for bit timing recovery to recover high speed burst mode signals. A wave forming filter for reverse-modulation of OQPSK signals is proposed to increase extracted carrier signal-to-noise ratio. The proposed full digital burst modem VLSICs achieve a fast carrier/clock acquisition performance with a very low carrier slipping rate of 1 × 10^-8 event/symbol at an Eb/No of 4 dB with short preamble words less than 100 symbols. The developed CMOS VLSICs operate up to 60 Mb/s without an analog clock voltage controlled oscillator (VCO) in burst mode and for QPSK and OQPSK signals, which conventional methods cannot achieve