Wideband multi-channel receiver with fixed-frequency notch filter for interference rejection

A wideband multi-channel receiver, comprising:

• 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.

A wideband multi-channel receiver, comprising:

• 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.