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US 6,976,044 B1Granted
Narrowband interference canceller for wideband communication systems
AssigneeMaxim Integrated Products, Inc.
InventorMehdl Tavassoli Kilani
Life of this patent
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Abstract
A method and apparatus for adaptively removing interference from a signal. In one embodiment, the invention comprises an infinite impulse response (IIR) notch filter configured to receive a wideband signal and provide a filtered output signal, and a controller coupled to the notch filter to adaptively control the null frequency of the notch filter thereby removing narrowband interference from the received wideband signal. The controller may employ a gradient-based algorithm to detect the highest power frequency band in the output signal and modify the null frequency of the notch filter to minimize the power of the output signal.
Claims56
A signal filter device comprising:
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter, the second input signal being altered using a gradient-based algorithm modified so that a derivative of an error signal of the modified gradient-based algorithm is a delayed, filtered first input signal in order to minimize power of the output signal, the gradient-based algorithm is a modified, recursive prediction error algorithm.
A signal filter device comprising:
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter, the second input signal being altered using a gradient-based algorithm modified so that a derivative of an error signal of the modified gradient-based algorithm is a delayed, filtered first input signal in order to minimize power of the output signal, the gradient-based algorithm is a modified, pseudolinear regression algorithm.
A signal filter device comprising:
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal, the notch filter including a z-domain transfer function
- H
-
- (
- z
- )
- =
- a
-
- 1
- +
- k
- 1
-
- k
- 2
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- +
- z
- -
- 2
- 1
- -
- ak
- 1
-
- k
- 2
-
- k
- 3
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- -
- ak
- 4
-
- z
- -
- 2
- where the terms a, k1, k2, k3, k4, and k5 are filter parameters and absorbing scaling factors and h[n] is the second input signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter.
63 more elements
A communication device comprising:
- a receiving module including,
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter, the controller being configured to minimize the power of the output signal of the notch filter and to minimize the power of the output signal by varying the second input signal according to a gradient-based algorithm modified so that a derivative of an error signal of the modified gradient-based algorithm is a delayed, filtered first input signal in order to minimize power of the output signal, the gradient-based algorithm is a modified, pseudolinear regression algorithm.
1 more element
A communication device comprising:
- a receiving module including,
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter, the controller being configured to minimize the power of the output signal of the notch filter and to minimize the power of the output signal by varying the second input signal according to a gradient-based algorithm modified so that a derivative of an error signal of the modified gradient-based algorithm is a delayed, filtered first input signal in order to minimize power of the output signal, the modified gradient-based algorithm is a modified, recursive prediction error algorithm.
1 more element
A communication device comprising:
- a receiving module including;
- an infinite impulse response (IIR) notch filter configured to receive a first input signal and provide an output signal, the notch filter has the z-domain transfer function
- H
-
- (
- z
- )
- =
- a
-
- 1
- +
- k
- 1
-
- k
- 2
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- +
- z
- -
- 2
- 1
- -
- ak
- 1
-
- k
- 2
-
- k
- 3
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- -
- ak
- 4
-
- z
- -
- 2
- where the terms a, k1, k2, k3, k4, and k5 are the filter parameters and absorbing scaling factors and h[n] is the second input signal;
- and
- a controller coupled to the notch filter to receive the output signal and provide a second input signal to the notch filter to adaptively control the null frequency of the notch filter.
64 more elements
A method for filtering signal interference comprising:
- filtering by a notch filter a received signal to remove interference and provide an output signal, the notch filter including a z-domain transfer function
- H
-
- (
- z
- )
- =
- a
-
- 1
- +
- k
- 1
-
- k
- 2
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- +
- z
- -
- 2
- 1
- -
- ak
- 1
-
- k
- 2
-
- k
- 3
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- -
- ak
- 4
-
- z
- -
- 2
- where the terms a, k1, k2, k3, k4, and k5 are the filter parameters and absorbing scaling factors and h[n] is an adaptation input signal for the notch filter;
- and
- dynamically minimizing the power of the output signal by removing a frequency band.
63 more elements
A machine-readable medium having one or more instructions for adaptively filtering signal interference, which when executed by a processor, causes the processor to perform operations comprising:
- receiving a first signal;
- filtering the first signal to remove interference and provide an output signal, the filtering is accomplished by a notch filter including a z-domain transfer function
- H
-
- (
- z
- )
- =
- a
-
- 1
- +
- k
- 1
-
- k
- 2
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- +
- z
- -
- 2
- 1
- -
- ak
- 1
-
- k
- 2
-
- k
- 3
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- -
- ak
- 4
-
- z
- -
- 2
- where the terms a, k1, k2, k3, k4, and k5 are the filter parameters and absorbing scaling factors and h[n] is a second adaptation input signal for the notch filter, and minimizing the power of the output signal by removing a frequency band from the first signal.
62 more elements
A system for adaptively filtering signal interference comprising:
- means for filtering a first signal to remove interference and provide a second signal, the means for filtering includes a notch filter including a z-domain transfer function
- H
-
- (
- z
- )
- =
- a
-
- 1
- +
- k
- 1
-
- k
- 2
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- +
- z
- -
- 2
- 1
- -
- ak
- 1
-
- k
- 2
-
- k
- 3
-
- h
-
- [
- n
- ]
-
- k
- 5
-
- z
- -
- 1
- -
- ak
- 4
-
- z
- -
- 2
- where the terms a, k1, k2, k3, k4, and k5 are the filter parameters and absorbing scaling factors and h[n] is an adaptation input signal for the notch filter;
- and
- means for minimizing the power of the second signal by removing a frequency band from the first signal.
63 more elements
Dependencies are inferred from the claim text.