Wideband co-site interference reduction apparatus
First Claim
1. An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath comprising:
- a frequency hopped radio adapted to operate in dispersion environment, said radio having an instantaneously limited bandwidth communication channel operating over a substantially larger bandwidth;
transmission means, associated with said radio, for transmitting the signal having a phase slope delay over the bandwidth via a directly coupled reference path and a received coupled path and wherein said transmission means has a dead time;
delay means for variably adjusting the phase slope delay of the signal in one path relative to the other path to provide matching between said paths, thereby enhancing the performance of said radio.
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Accused Products
Abstract
An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. This interference cancellation system includes a frequency hopped radio adapted to operate in a dispersion environment. This frequency hopped radio has an instantaneously limited bandwidth communication channel operating over a substantially larger bandwidth. Transmission of a signal from the frequency hopped radio is via a directly coupled reference path and a received coupled path. A delay means is used for variably adjusting the phase slope delay of the signal in one path relative to the other path. The system employs an amplitude slope means for variably adjusting the amplitude slope of the signal in one path relative to the other path. A digital controlling means, associated with the delay means and the amplitude slope means, provides improved matching of the signal in each path, thereby enhancing the performance of the co-site interference reduction system.
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Citations
35 Claims
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1. An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath comprising:
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a frequency hopped radio adapted to operate in dispersion environment, said radio having an instantaneously limited bandwidth communication channel operating over a substantially larger bandwidth;
transmission means, associated with said radio, for transmitting the signal having a phase slope delay over the bandwidth via a directly coupled reference path and a received coupled path and wherein said transmission means has a dead time;
delay means for variably adjusting the phase slope delay of the signal in one path relative to the other path to provide matching between said paths, thereby enhancing the performance of said radio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath comprising:
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a frequency hopped radio adapted to operate in dispersion environment, said radio having an instantaneously limited bandwidth communication channel operating over a substantially larger band;
transmission means, associated with said radio, for transmitting the signal having an amplitude slope over the band via a directly coupled reference path and a received coupled path;
amplitude slope means for variably adjusting the amplitude slope of the signal in one path relative to the other path to provide matching between said paths, thereby enhancing the performance of said radio. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath comprising:
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a frequency hopped radio adapted to operate in dispersion environment, said radio having an instantaneously limited bandwidth communication channel operating over a substantially larger bandwidth;
transmission means, associated with said radio, for transmitting the signal having a phase slope delay and an amplitude slope over the bandwidth via a directly coupled reference path and a received coupled path;
delay means for variably adjusting the phase slope delay of the signal in one path relative to the other path;
amplitude slope means for variably adjusting the amplitude slope of the signal in one path relative to the other path;
digital controlling means, associated with said delay means and said amplitude slope means, for improving the matching of the signal in each path, thereby enhancing the performance of said radio. - View Dependent Claims (30, 31, 32, 33, 34)
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35. An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath comprising:
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a frequency hopped radio adapted to operate in dispersion environment, said radio having an instantaneously limited bandwidth communication channel operating over a substantially larger band;
transmission means, associated with said radio, for transmitting the signal having an amplitude slope over the band via a directly coupled reference path and a received coupled path;
amplitude slope means for variably adjusting the amplitude slope of the signal in one path relative to the other path to provide matching between said paths;
wherein said amplitude slope means further comprises control means for adjusting the variable amplitude slope of the signal in real-time and a transversal filter having only two taps and having programmable weights, selectable by said control means, such that the phase and pass band of the band can be adjusted; and
wherein said filter has a center frequency, a pass band envelope, and a main lobe bandwidth that is substantially greater than the signal bandwidth, and wherein the amplitude slope adjusted is implemented by adjusting the center frequency of said filter causing the instantaneous band to be conditioned by a separate portion of the pass band envelope, whereby the performance of said radio is enhanced;
an amplitude tilt network associated with said transversal filter;
thereby enhancing the performance of said radio.
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Specification