Suppression of adjacent channel interference by adaptive channel filtering in mobile radio receivers
First Claim
1. An adaptive channel filter for a receiver unit for a mobile communications system, comprising a channel filter with a variable pass bandwidth, which comprises a first low-pass filter on the input side, a bandpass filter which is connected in parallel with the channel filter, a means for controlling the pass bandwidth of the channel filter as a function of the adjacent channel interference, having a first input which is connected to an output of the first low-pass filter, and having a second input which is connected to an output of the bandpass filter, and a means for removal of any DC signal component or DC component in the signal path which contains the first low-pass filter.
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Accused Products
Abstract
A channel filter (200) with a variable pass bandwidth has a first low-pass filter (200.2) on the input side and is driven by a means (30) for controlling the pass bandwidth as a function of the adjacent channel interference. A first input of the control means (30) is connected to the first low-pass filter (200.2), and a second input is connected to a bandpass filter (200.4) which is connected in parallel with the channel filter (200). The signal path which contains the low-pass filter (200.2) contains a means (37) for removing a DC signal component or DC component.
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Citations
19 Claims
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1. An adaptive channel filter for a receiver unit for a mobile communications system, comprising
a channel filter with a variable pass bandwidth, which comprises a first low-pass filter on the input side, a bandpass filter which is connected in parallel with the channel filter, a means for controlling the pass bandwidth of the channel filter as a function of the adjacent channel interference, having a first input which is connected to an output of the first low-pass filter, and having a second input which is connected to an output of the bandpass filter, and a means for removal of any DC signal component or DC component in the signal path which contains the first low-pass filter.
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9. A method for setting the variable pass bandwidth of a channel filter, having the following steps:
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filtering of an input signal with a bandpass filter for production of a signal which is characteristic of an interference signal in an interference signal path, and having a low-pass filter for production of a signal which is characteristic of a payload signal in a payload signal path and for removal of the DC signal component in the payload signal path, calculating two variables which are characteristic of the signal powers of the two filtered signals, and setting of the pass bandwidth of the channel filter as a function of a comparison of the calculated variables. - View Dependent Claims (10, 11)
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12. An adaptive channel filter for a receiver unit for a mobile communications system, comprising
a channel filter with a variable pass bandwidth, which comprises a first low-pass filter on the input side, a bandpass filter which is connected in parallel with the channel filter, a pass bandwidth controller which controls the pass bandwidth as a function of the adjacent channel interference, comprising a first input connected to an output of the first low-pass filter, and a second input connected to an output of the bandpass filter, and a DC component removal unit arranged in the signal path which contains the first low-pass filter.
Specification