초록 ▼

A direct sequence spread spectrum communication system in a digital cordless telephone having a basestation and a handset that each implement an extended .linevert split.EE.linevert split.+.linevert split.E.linevert split.-.linevert split.L.linevert split.-.linevert split.LL.linevert split. time tra

A direct sequence spread spectrum communication system in a digital cordless telephone having a basestation and a handset that each implement an extended .linevert split.EE.linevert split.+.linevert split.E.linevert split.-.linevert split.L.linevert split.-.linevert split.LL.linevert split. time tracking system and peak matched filter demodulation within a related window to permit one sample per chip analog-to-digital conversion and demodulation for longer code sequences (providing savings in hardware and complexity) and to permit enhanced two sample per chip analog-to-digital conversion and demodulation for shorter code sequences (providing more robust fading immunity).

대표청구항 ▼

[ What is claimed is:] [16.] In a digital cordless telephone having a basestation connectable to a switched telephone network and a handset, said basestation and handset communicating over an RF link using direct sequence spread spectrum modulation, said basestation and said handset each connected t

[ What is claimed is:] [16.] In a digital cordless telephone having a basestation connectable to a switched telephone network and a handset, said basestation and handset communicating over an RF link using direct sequence spread spectrum modulation, said basestation and said handset each connected to receive and demodulate digital in-phase and quadrature baseband signals using analog-to-digital converters and matched filters operating at a sample rate to produce complex in-phase and quadrature digital data, and a demodulation circuit, an improvement comprising:extended time tracking means for defining and maintaining a multiple sample demodulation window around a centroid of correlation energy for each bit interval; andmeans for demodulating the in-phase and quadrature digital data that has the highest energy content within at least a portion of the demodulation window, the portion including a sample at a predicted center of the multiple sample demodulation window and at least two adjacent samples; andmeans for selecting one of the demodulated samples as best representing valid data.