VLSI Implemented 60 Mb/s QPSK/OQPSK Burst Digital Demodulator for Radio Application

Yoichi MATSUMOTO  Kiyoshi KOBAYASHI  Tetsu SAKATA  Kazuhiko SEKI  Shuji KUBOTA  Shuzo KATO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.12   pp.1873-1880
Publication Date: 1994/12/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multimedia, Analog and Processing LSIs)
Category: Multimedia System LSIs
Keyword: 
demodulator,  carrier recovery,  bit-timing recovery,  VLSI,  TDMA,  

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Summary: 
This paper presents a fully digital high speed (60 Mb/s) Quadrature Phase Shift Keying (QPSK)/Offset QPSK (OQPSK) burst demodulator for radio applications, which has been implemented on a 0.5 µm Complementary Metal Oxide Semiconductor (CMOS) master slice Very Large Scale Integrated circuit (VLSI). The developed demodulator VLSI eliminates analog devices such as mixers, phase-shifters and Voltage Controlled Oscillator (VCO) for bit-timing recovery, which are used by conventional high-speed burst demodulators. In addition to the fully digital implementation, the VLSI achieves fast carrier and bit-timing acquisition in burst modes by employing a reverse-modulation carrier recovery scheme with a wave-forming filter for OQPSK operation, and a bit-timing recovery scheme with bit-timing estimation and interpolation using a pulse-shaping filter. Results of performance evaluation assuming application in Time Division Multiple Access (TDMA) systems show that the developed VLSI achieves excellent bit-error-rate and carrier-slipping-rate performance at high speed (60 Mb/s) with short preamble words (less than 100 symbols) in low Eb/No environments.