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US 6,477,196 B1Granted
Direct sequence spread spectrum communications receiver and method for efficient narrow-band signal excision
AssigneeRockwell Collins, Inc.
InventorsChristopher J. Swanke, Steven L. White
Life of this patent
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Abstract
A method of excising one or more narrow-band interfering signals in a direct sequence spread spectrum receiver that performs a magnitude spectral analysis on baseband signals in a detection channel to determine which frequency bins in the spectral analysis output contain the interfering narrow-band signals by comparing the magnitude of the signals in the frequency bins to a threshold. The corrupted frequency bins are determined by the signal magnitudes exceeding the threshold and band reject filters excise the narrow-band signals in the signal channel in accordance with the corrupted frequency bins.
Claims13
A method of excising one or more narrow-band interfering signals and obtaining a desired signal in a direct sequence spread spectrum communications receiver comprising:
- receiving an input signal containing the one or more narrow-band interfering signals and a desired direct sequence spread spectrum signal;
- maintaining a constant input signal level;
- converting the input signal into a baseband signal;
- performing a spectral analysis on the baseband signal to obtain spectral analysis output signals;
- determining which spectral analysis output signals contain the one or more narrow-band interfering signals;
- positioning band-reject filters to filter the baseband signal to excise the one or more narrow-band interfering signals according to the spectral analysis output signals determined to contain the one or more narrow-band interfering signals;
- and
- demodulating the desired direct sequence spread spectrum signal in the filtered baseband signal to obtain the desired signal.
5 more elements
A method of excising one or more narrow-band interfering signals and obtaining a desired signal in a direct sequence spread spectrum communications receiver comprising:
- receiving an input signal containing the one or more narrow-band interfering signals and a desired direct sequence spread spectrum signal;
- controlling the input signal with an automatic gain control signal to maintain a constant input signal level;
- down converting the input signal to an IF signal;
- digitizing the IF signal;
- down converting the digitized IF signal into an I/Q baseband signal;
- routing the I/Q baseband signal into a detection channel wherein the detection channel performs the steps comprising:
- performing a spectral analysis on the I/Q baseband signal;
- detecting magnitudes of the I/Q baseband signal spectral analysis output signals in frequency bins;
- generating the automatic gain control signal from the lowest magnitude spectral analysis signals in the frequency bins;
- comparing the magnitudes of the spectral analysis output signals in the frequency bins to a threshold;
- and
- determining corrupted frequency bin numbers containing the one or more narrow-band interfering signals when the frequency bins contain signals that exceed the threshold;
- routing the I/Q baseband signal into a signal channel wherein the signal channel performs the step of positioning frequency selectable band-reject filters to filter the I/Q baseband signal to excise the one or more narrow-band interfering signals from the signal channel signal according to the corrupted frequency bin numbers containing the one or more narrow-band interfering signals exceeding the threshold;
- and
- demodulating the desired direct sequence spread spectrum signal in the filtered I/Q baseband signal to obtain the desired signal.
12 more elements
A direct sequence spread spectrum receiver comprising:
- an antenna for receiving an input signal containing one or more narrow-band interfering signals and a desired direct sequence spread spectrum signal;
- a down converter connected to the antenna for controlling the input signal level and down converting the input signal to a baseband signal;
- a detection channel connected to the down converter for receiving the baseband signal said detection channel further comprising:
- a spectral analysis function for performing a spectral analysis on the baseband signal and generating spectral analysis output signals in frequency bins;
- a bin magnitude detector connected to the spectral analysis function for detecting magnitudes of the spectral analysis output signals in the frequency bins;
- an automatic gain control function connected to the bin magnitude detector for generating an AGC control signal from the lowest magnitude spectral analysis output signals in the frequency bins;
- and
- a decision logic function connected to the bin magnitude detector for comparing the magnitude of the spectral analysis output signals in the frequency bins to a threshold and for determining corrupted frequency bin numbers containing the one or more narrow-band interfering signals when the frequency bins contain signals exceeding the threshold;
- a signal channel for receiving the baseband signal and for filtering the baseband signal to excise the one or more narrow-band interfering signals from the signal channel according to the spectral analysis output signals indicating the presence of one or more narrow-band interfering signals;
- and
- a demodulator for demodulating the desired direct sequence spread spectrum signal contained in the baseband signal in the signal channel.
8 more elements
A direct sequence spread spectrum communications receiver for excising one or more narrow-band interfering signals and receiving a desired signal comprising:
- an antenna for receiving an input signal containing the one or more narrow-band interfering signals and the desired signal;
- an AGC controller connected to the antenna for controlling the input signal with an AGC control signal to maintain a constant input signal level;
- a mixer for down converting the input signal received from the AGC controller to an IF signal;
- an A/D converter for digitizing the IF signal received from the mixer;
- a digital down converter for down converting the digitized IF signal into an I/Q baseband signal;
- a detection channel connected to the digital down converter for receiving the I/Q baseband signal wherein the detection channel further comprises:
- a spectral analysis function for performing a spectral analysis on the l/Q baseband signal and generating spectral analysis output signals in frequency bins;
- a bin magnitude detector connected to the spectral analysis function for detecting magnitudes of the I/Q baseband signal spectral analysis output signals in the frequency bins;
- an automatic gain control function connected to the bin magnitude detector for generating the automatic gain control signal from the lowest magnitude I/Q baseband spectral analysis output signals in the frequency bins;
- and
- a decision logic function connected to the bin magnitude detector for comparing the magnitude of the I/Q baseband signal spectral analysis output signals in the frequency bins to a threshold and for determining corrupted frequency bin numbers containing the one or more narrow-band interfering signals when the frequency bins contain signals exceeding the threshold;
- a signal channel for receiving the I/Q baseband signal wherein the signal channel further comprises frequency selectable band-reject filters to excise the one or more narrow-band interfering signals from the signal channel signal according to the corrupted frequency bin numbers;
- and
- a demodulator for demodulating the I/Q baseband signal in the signal channel to obtain the desired signal.
11 more elements
Dependencies are inferred from the claim text.