Pulse or digital communications – Receivers – Interference or noise reduction
Patent
1994-04-28
1996-05-21
Chin, Stephen
Pulse or digital communications
Receivers
Interference or noise reduction
375350, 375232, 455137, H04B 712, H04L 102
Patent
active
055197353
ABSTRACT:
An original signal, different portions of which are captured by two or more different receivers, is reconstructed from the outputs of the various receivers. In a first embodiment, signal reconstruction is achieved by first converting the analog receiver outputs into digital signals and then shifting the frequency of at least one of the digital signals such that a frequency difference is introduced between at least two of the digital signals. Thereafter, each digital signal is processed through a corresponding filter (38, 40) to derive filtered signals. These filtered signals are combined to derive a primary output signal which is a representation of the original signal. After the primary output signal is derived, it is passed on to an error determiner (44) where an error component is computed. This error component is used to adjust the parameters of the filters (38, 40) in such a manner as to reduce the error component. In an alternative method, the original signal is reconstructed by first processing all but one of the digital signals through a corresponding (114) filter to derive one or more filtered signals. The filtered signal or signals are combined with the digital signal which was not filtered to derive an intermediate output signal. The intermediate output signal is processed through another filter (120) to derive a primary output signal representative of the original signal. As with the first method, the primary output signal is sent to an error determiner (126) where an error component is computed. This error component is used to adjust the parameters of all of the filters (114, 120) to reduce the error component. The present invention provides a robust solution for reconstructing multichannel signals which is capable of tolerating variable frequency overlaps, relative time delays between signals on the multiple channels, and some degree of frequency offset.
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Rice Bart F.
Wilhoyte Michael E.
Bocure Tesfaldet
Chin Stephen
Lockheed Missiles & Space Co., Inc.
Radlo Edward J.
Truong Phong K.
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