Pulse or digital communications – Pulse code modulation – Differential
Patent
1997-12-17
2000-11-28
Chin, Stephen
Pulse or digital communications
Pulse code modulation
Differential
375355, 375363, 375371, 327146, 327152, 327153, 327161, H04B 1406
Patent
active
061544973
ABSTRACT:
A conversion (20, 120, 220) system for converting an analog signal (18, 118, 218) to a digital signal (54, 154, 254) in a communications system (10), the conversion system (20, 120, 220) including an oversampled analog-to-digital converter modulator (24, 124, 224) for receiving an oversampling-clock signal (29, 129, 229) and a transmitted analog signal (18, 118, 218), the oversampled analog-to-digital converter modulator (24, 124, 224) operable to sample the analog signal (18, 118, 218) and to convert the analog signal (18, 118, 218) to a first digital signal (32, 132, 232), a time adjustor (41, 141, 241) coupled to the oversampled analog-to-digital converter modulator (24, 124, 224) for receiving the first digital signal (32, 132, 232) and a first adjustment signal (48, 148, 248), and for producing an output digital signal (54, 154, 254), and a digital signal processor unit (56, 156, 256) coupled to the time adjustor (41, 141, 241) for receiving the output digital signal (54, 154, 254) and performing timing recovery thereon to determine if any adjustment of the time adjustor (41, 141, 241) is required to minimize phase error and frequency error, and for producing the first adjustment signal (48, 148, 248) based on the results of the timing recovery. One time adjustor (41) includes a programmable delay line (46). Another time adjustor (141, 241) includes a two-part decimation filter (126, 226), a clock control (133, 233), and a clock divider (162, 262). An interpolation filter (270) may also be used as an aspect of the time adjustor (241). A method of converting an analog signal (18, 118, 218) to a digital signal (54, 154, 254) is also presented.
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Fattaruso John W.
Gatherer Alan
Brady III Wade James
Chin Stephen
Ha Dac V.
Holmbo Dwight N.
Telecky Jr. Frederick J.
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