Wideband multi-channel receiver with fixed-frequency notch filter for interference rejection
First Claim
1. A wideband multi-channel receiver, comprising:
- an antenna configured to receive a radio frequency band comprising an aviation VHF communication band, an aviation VHF navigation band, an aviation L-band, or combinations thereof;
a variable attenuator responsive to the radio frequency signal from the antenna and configured to protect against signal overload of the receiver;
a band select band-pass filter coupled to an output of the variable attenuator and configured to pass a selected radio frequency band while rejecting signals outside of the selected radio frequency band;
a first tunable notch filter coupled to an output of the band-pass filter and configured to reject an in-band interference signal more than 1 MHz away from the selected radio frequency band;
a low-noise amplifier coupled to the output of the first tunable notch filter;
a second tunable notch filter coupled to an output of the low-noise amplifier and configured to reject an additional in-band interference signal more than 1MHz away from the selected radio frequency band;
a mixer coupled to an output of the second tunable notch filter and configured to translate the selected radio frequency band to an intermediate frequency band;
a tunable local oscillator coupled to an input of the mixer;
a plurality of fixed-frequency notch filters each selectively connectable to an output of the mixer, the fixed-frequency notch filters each centered at a different intermediate frequency band and configured to reject at least one interference signal while passing remaining signals in the intermediate frequency band;
an automatic gain control amplifier selectively connectable to an output of each of the fixed-frequency notch filters;
a wide-band anti-alias filter coupled to an output of the automatic gain control amplifier;
an analog-to-digital converter coupled to an output of the anti-alias filter; and
a digital processing system coupled to an output of the analog-to-digital converter.
1 Assignment
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Accused Products
Abstract
A wideband multi-channel receiver comprises an antenna configured to receive a radio frequency band comprising an aviation VHF communication band, an aviation VHF navigation band, an aviation L-band, or combinations thereof. A band-pass filter is in signal communication with the antenna, and a low-noise amplifier is in signal communication with the band-pass filter. A mixer is in signal communication with the low-noise amplifier and is configured to translate a radio frequency band to an intermediate frequency (IF) band. A tunable local oscillator is in signal communication with the mixer. At least one fixed-frequency notch filter is in signal communication with the mixer, with the notch filter configured to reject at least one interference signal in the IF band while passing remaining signals in the IF band. An analog-to-digital converter is in signal communication with the notch filter and is configured to convert the remaining signals in the IF band to digital signals. A digital processing system is in signal communication with the analog-to-digital converter.
84 Citations
16 Claims
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1. A wideband multi-channel receiver, comprising:
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an antenna configured to receive a radio frequency band comprising an aviation VHF communication band, an aviation VHF navigation band, an aviation L-band, or combinations thereof; a variable attenuator responsive to the radio frequency signal from the antenna and configured to protect against signal overload of the receiver; a band select band-pass filter coupled to an output of the variable attenuator and configured to pass a selected radio frequency band while rejecting signals outside of the selected radio frequency band; a first tunable notch filter coupled to an output of the band-pass filter and configured to reject an in-band interference signal more than 1 MHz away from the selected radio frequency band; a low-noise amplifier coupled to the output of the first tunable notch filter; a second tunable notch filter coupled to an output of the low-noise amplifier and configured to reject an additional in-band interference signal more than 1MHz away from the selected radio frequency band; a mixer coupled to an output of the second tunable notch filter and configured to translate the selected radio frequency band to an intermediate frequency band; a tunable local oscillator coupled to an input of the mixer; a plurality of fixed-frequency notch filters each selectively connectable to an output of the mixer, the fixed-frequency notch filters each centered at a different intermediate frequency band and configured to reject at least one interference signal while passing remaining signals in the intermediate frequency band; an automatic gain control amplifier selectively connectable to an output of each of the fixed-frequency notch filters; a wide-band anti-alias filter coupled to an output of the automatic gain control amplifier; an analog-to-digital converter coupled to an output of the anti-alias filter; and a digital processing system coupled to an output of the analog-to-digital converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wideband multi-channel receiver, comprising:
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an antenna configured to receive a radio frequency signal comprising an aviation VHF navigation band; a variable attenuator responsive to the radio frequency signal from the antenna and configured to protect against signal overload of the receiver; at least one band-pass filter in signal communication with the variable attenuator and configured to pass a selected radio frequency band while rejecting out-of-band interference signals outside of the selected radio frequency band; a low-noise amplifier in signal communication with the band-pass filter; a mixer in signal communication with the low-noise amplifier and configured to translate the selected radio frequency band to an intermediate frequency band; a tunable local oscillator coupled to an input of the mixer; one or more fixed-frequency notch filters selectively connectable to an output of the mixer, the fixed-frequency notch filters configured to reject at least one narrow frequency band while passing remaining signals in the intermediate frequency band; an automatic gain control amplifier selectively connectable to an output of the fixed-frequency notch filters; a wide-band anti-alias filter coupled to an output of the automatic gain control amplifier; an analog-to-digital converter coupled to an output of the anti-alias filter; and a digital processing system coupled to an output of the analog-to-digital converter. - View Dependent Claims (10, 11, 12)
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13. A wideband multi-channel receiver, comprising:
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an antenna configured to receive a radio frequency band comprising an aviation L-band; a variable attenuator responsive to the radio frequency signal from the antenna and configured to protect against signal overload of the receiver; a band-pass filter in signal communication with the variable attenuator and configured to pass a selected radio frequency band while rejecting signals outside of the selected radio frequency band; a low-noise amplifier in signal communication with the band-pass filter; a tunable notch filter coupled to an output of the low-noise amplifier and configured to reject an in-band interference signal more than 1 MHz away from the selected radio frequency band; a mixer in signal communication with the tunable notch filter and configured to translate the selected radio frequency band to an intermediate frequency band; a tunable local oscillator coupled to an input of the mixer; an automatic gain control amplifier in signal communication with the mixer; a wide-band anti-alias filter coupled to an output of the automatic gain control amplifier; an analog-to-digital converter coupled to an output of the anti-alias filter; and a digital processing system coupled to an output of the analog-to-digital converter. - View Dependent Claims (14, 15, 16)
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Specification