A New Five-Bit 128-Tone Sigma-Delta Modulation D/A and A/D Converters for UWB-OFDM Transceiver

For the purpose of reducing the quantization noise and power consumption of UWB-OFDM transceiver, a new time domain-based interpolator and decimator structure is proposed to realize five-bit D/A and A/D converters in the five-bit 128-tone sigma-delta modulation (SDM) UWB-OFDM transceiver. The five-bit 128-tone SDM UWB-OFDM transceiver using time domain-based interpolator and decimator in place of time spreader and de-spreader can obtain time-domain spread spectrum processing gain and reduce quantization noise simultaneously. The structure of the five-bit 128-tone SDM A/D converter, which employs 32 parallel analog SDM circuits without up-sampling, is designed. Simulation results demonstrate that BER of the proposed five-bit 128-tone SDM D/A and A/D converters based on time domain-based interpolator and decimator scheme can satisfy the performance requirements of the five-bit 128-tone SDM UWB-OFDM transceiver for the QPSK, 16-QAM and 64-QAM modulations.