Demodulators – Amplitude modulation demodulator – Having specific distortion – noise or other interference...
Patent
1986-11-04
1988-12-27
LaRoche, Eugene R.
Demodulators
Amplitude modulation demodulator
Having specific distortion, noise or other interference...
329135, H03D 318
Patent
active
047943416
ABSTRACT:
A filter, in which digital representations of a signal are stored as samples in a store (8) preferably in the order of their occurrence. Multipliers (9) multiply the samples by coefficients (C1 to C36) representing a function with which the samples are to be convolved. To compensate for the variable time delays in the signal, sets of coefficients representing the function with different time delays are stored. The set to be convolved with the signal is chosen in dependence upon the time delay of the signal. A signal indicative of the time delay is derived from an input to the shift register and fed-forward. The filter is preferably used in a digital demodulator of phase and/or amplitude modulated signals. The function is then an impulse function defining (at least in part) a desired frequency response of the filter, and the filter corrects the timing of symbols represented by the signal. In the digital demodulator, the symbol timing recovery and correction (4) takes place before carrier phase recovery (5) and demodulation.
REFERENCES:
patent: 4528512 (1985-07-01), Yoshida
patent: 4620159 (1986-10-01), Yoshida et al.
McVerry, Performance of a Fast Carrier-Recovery Scheme for Burst-Format DQPSK Transmission over Satellite Channels, Digital Processing of Signals, In Communications, Loughborough University (Apr. 22-26, 1985): 165-172.
A. J. Viterbi, A. M. Viterbi, Non-Linear Estimation of PSK-Modulated Carrier Phase with Application to Burst Digital Transmission, IEEE Transactions on Information Theory, vol. IT-29, No. 4 (Jul., 1983): 543-551.
H. Kobayashi, Simultaneous Adaptive Estimation and Decision Algorithm for Carrier Modulated Data Transmission Systems, IEEE Transactions on Communications Technology, vol. COM-19, No. 3 (Jun. 1971): 268-280.
R. J. Sherman, Quadri-Phase-Shift-Keyed Signal Detection with Noisy Reference Signal, Eascon '69 Record: 45-52.
K. Feher, Digital Communications, Prentice-Hall, 1983.
Signal Processors Limited, "QBM 2048 Digital Mode Brochure".
M. Mueller and K. Mueller, "Adaptive Timing Recovery in Digital Synchronous Data Receivers".
Barton Stephen K.
Terrell Peter M.
LaRoche Eugene R.
Pascal Robert J.
Signal Processors Limited
LandOfFree
Digital filters and demodulators does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital filters and demodulators, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital filters and demodulators will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-870064