A digital intermediate frequency demodulator for /spl pi//4 DQPSK based on hard limiter

This paper proposes a new digital intermediate frequency (D-IF) demodulation scheme for pi/4 differential quadrature phase shift keying (DQPSK) modulation based on hard limiter. After converting the IF signal into a 2-level signal, all following signal processing is implemented in the digital domain. The proposed scheme demonstrates several attractive attributes: compared with traditional D-IF demodulator, the power consuming and complex analog-to-digital converter (ADC) is not necessary; on the other hand, the scheme outperforms the normal D-IF demodulator based on hard limiter with better bit error rate (BER) performance and lower sampling rate