Pulse or digital communications – Receivers – Angle modulation
Patent
1994-03-03
1996-08-27
Chin, Stephen
Pulse or digital communications
Receivers
Angle modulation
329318, 455 63, 455 65, H03D 322
Patent
active
055508685
ABSTRACT:
A .pi./4 delay spread detection and compensation arrangement effectively detects distortion due to multipath delay spread in a digital channel and compensates for this distortion with minimum circuit complexity. An improvement in the bit error rate performance for a differential detector in the receiver is achieved through use of a detected direct current (DC) component, which is proportional to the amount of multipath delay spread on the digital channel. This DC component is used in the differential detector for compensating for this delay spread. In addition, the differential detector also provides a channel quality measure of the level of delay spread on the digital channel for use by the receiver in selecting either the differential detector or an equalizer for decoding of the data on the digital channel. When the level of delay spread is low, a processor used by the equalizer is freed for other computational tasks or, when the bit error rate permits, is not used at all thereby realizing a reduction in power consumption in the receiver.
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Byong Jin Cho, Hong Zhou, Susumu Yoshida, Tsutomu Takeuchi and Dae Young Kim "A Simple Multipath Delay Time Detection Method for .pi./4 Shift QPSK In Digital Mobile/Portable Communications" 41st IEEE Vehicular Technology Conference, St. Louis, MO, USA. May 19-22, 1991, pp. 7-12, 1991.
Susumu Yoshida, Atsuo Hirai, Guan Leng Tan, Hong Zhou and Tsutomu Takeuchi, "In-Service Monitoring Of Multipath Delay-Spread and C/1 For QPSK Signal" Department of Electronics, Faculty of Engineering, Kyoto, University, Kyoto 606-01, Japan, IEEE, Feb. 1992 pp. 592-595.
Chin Stephen
Ghebretinsae T.
Lucent Technologies - Inc.
Williamson Samuel R.
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