Pulse or digital communications – Repeaters – Testing
Patent
1988-03-30
1989-08-22
Griffin, Robert L.
Pulse or digital communications
Repeaters
Testing
3701101, 332 10, H04B 138
Patent
active
048603082
ABSTRACT:
A data modem communication system includes a data modem transmitter adapted to transmit data on a main channel at a relatively high bit rate and to transmit data at a relatively low bit rate on a secondary channel. At the receiver, a single analog-to-digital converter (54) supplies digital signals via a notch filter (58) to the main channel receiver (60) and to the secondary channel receiver (62) wherein a single IIR low-pass digital filter (110) is utilized for processing at three different sample rates to eliminate the main channel signal with frequency conversion taking place between processing at the first and second sample rates. The invention enables the provision of a reliable secondary channel while using a minimum amount of circuitry for complex-valued digital signal processing.
REFERENCES:
patent: 4273955 (1981-06-01), Armstrong
patent: 4301417 (1981-11-01), Jansen et al.
patent: 4310721 (1982-01-01), Manley et al.
patent: 4362997 (1982-12-01), van Driest
patent: 4425665 (1984-01-01), Stauffer
patent: 4521891 (1985-06-01), Biba et al.
patent: 4528519 (1985-07-01), van Driest
patent: 4530104 (1985-07-01), Kamerman
patent: 4577334 (1986-03-01), Boer et al.
patent: 4734920 (1988-03-01), Betts
U.S. patent application Ser. No. 163,357, assigned to NCR Corporation, filed Mar. 2, 1988, "Multipoint Data Modem Communication System", Jan Boer et al.
Bennett, W. R. and Davey, J. R.; Data Transmission; McGraw-Hill, New York, 1965; pp. 182-190.
Lucky, R. W., Salz, Jr. and Weldon, E. J.; Principles of Data Communication; McGraw-Hill, New York, 1968; pp. 226-232.
Bird, J. S.; Error Performance of Binary NCFSK in the Presence of Multiple Tone Interference and System Noise; IEEE Transactions on Communications, vol. COM-33, No. 3, Mar. 1985; pp. 203-209.
Sundberg, C. E.; Continuous Phase Modulation; IEEE Communications Magazine, vol. 24, No. 4, Apr. 1986; pp. 25-38.
Ansari, R. and Liu, B.; A Class of Low Noise Computationally Efficient Recursive Digital Filters; Proceedings IEEE International Symposium Circuits and Systems, Apr. 1981; pp. 550-553.
Ansari, R. and Liu, B.; A Class of Low Noise Computionally Efficient Recursive Digital Filters with Applications to Sampling Rate Alterations; IEEE Transactions on Acoustics, Speech & Signal Processing, vol. ASSP-33, No. 1, 2/85.
Jennings, F.; Practical Data Communications-Modems, Networks, Protocols; Blackwell Scientific Publications, Oxford, 1986, p. 48.
CCITT-Data Communication Over the Telephone Network-vol. VIII-Fascicle VIII.1-Recommendations of the V-Series; Geneva, 1985, Recommendation V29; pp. 203-215.
Carey, M. B., Chen, H. T.; Descloux, A., Ingle, J. F. and Clark, K. I.; 1982/83, End Office Connection Study-AT&T Bell Laboratories Technical Journal, vol. 63, No. 9, Nov. 1984; pp. 2059-2119.
Motorola Inc., 2605 Series Data User Manual, Aug. 1984, Motorola Inc., Mansfield, Mass.
Racal Milgo's 14400 Bit/s System Modem Omnimode 14.4 Manual.
Haagh Johannes P. N.
Kamerman Adriaan
Chin Stephen
Griffin Robert L.
Hawk Jr. Wilbert
Lavin Richard W.
NCR Corporation
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