Receiver for phase-shift modulated carrier signals
First Claim
Patent Images
1. A receiver for recovering digital data modulated upon a carrier waveform in a digital communication system comprising:
- (a) first frequency generating means responsive to a first servo control signal for producing first and second local oscillator signals;
(b) mixing means coupled to said first frequency generating means for mixing the modulated carrier with each of said first and second local oscillator signals to form first and second recovered modulation signals, respect- ively;
(c) first filtering means coupled to said mixing means for increasing the signal-to-noise ratio in said first and second recovered modulation signals;
(d) second filtering means responsive to a first system timing signal and coupled to said first filtering means for further increasing the signal-to-noise ratio in said first and second recovered modulation signals to form data and servo signals, respectively; and
(e) first multiplier means coupled to said second filtering means for multiplying said data and servo signals to form the first servo control signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A receiver for recovering digital data from a phase-shift modulated carrier in a data communications system employs a matched filter within the servo loop controlling the local oscillator frequency to increase the signal to noise ratio of the receiver. Thus signals having an amplitude less than the amplitude of harmonics of the carrier can be detected. In the preferred embodiment, the matched filter comprises an integrate and dump filter which integrates at the received data baud rate. ,
-
Citations
22 Claims
-
1. A receiver for recovering digital data modulated upon a carrier waveform in a digital communication system comprising:
-
(a) first frequency generating means responsive to a first servo control signal for producing first and second local oscillator signals; (b) mixing means coupled to said first frequency generating means for mixing the modulated carrier with each of said first and second local oscillator signals to form first and second recovered modulation signals, respect- ively; (c) first filtering means coupled to said mixing means for increasing the signal-to-noise ratio in said first and second recovered modulation signals; (d) second filtering means responsive to a first system timing signal and coupled to said first filtering means for further increasing the signal-to-noise ratio in said first and second recovered modulation signals to form data and servo signals, respectively; and (e) first multiplier means coupled to said second filtering means for multiplying said data and servo signals to form the first servo control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
Specification