Cross-channel interference
First Claim
1. In a multi-channel electrical communication system, a method of estimating the interference level in a test channel due to the intermodulation of two or more other channels, where each channel is centered upon a carrier frequency, the method comprising, for a given m-th order mode, the steps of:
- identifying at least one set of carrier frequencies, the m-th order linear combination of which gives rise substantially to the carrier frequency of said test channel; and
for the at least one identified set of carrier frequencies, tuning signal generators to respective ones of the carrier frequencies, applying the generated signals to an input of the communication system, and measuring at an output of the system the intermodulation interference at the carrier frequency of the test channel.
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Accused Products
Abstract
In a multi-channel electrical communication system 1, a method of estimating the interference level in a test channel due to the intermodulation of two or more other channels, where each channel is centred upon a carrier frequency. The method comprises, for a given m-th order mode, an initial step of identifying the set(s) of carrier frequencies, the m-th order linear combination of which gives rise substantially to the carrier frequency of said test channel. This process is carried out by a computer 2. For the or each of the identified set of carrier frequencies, signal generators 3 are tuned to respective ones of the carrier frequencies. The generated signals are applied to an input of the communication system 1, and the intermodulation interference at the carrier frequency of the test channel is measured at an output of the system 1.
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Citations
11 Claims
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1. In a multi-channel electrical communication system, a method of estimating the interference level in a test channel due to the intermodulation of two or more other channels, where each channel is centered upon a carrier frequency, the method comprising, for a given m-th order mode, the steps of:
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identifying at least one set of carrier frequencies, the m-th order linear combination of which gives rise substantially to the carrier frequency of said test channel; and
for the at least one identified set of carrier frequencies, tuning signal generators to respective ones of the carrier frequencies, applying the generated signals to an input of the communication system, and measuring at an output of the system the intermodulation interference at the carrier frequency of the test channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Apparatus for testing a multi-channel communication system to estimate the interference level in a test channel due to the intermodulation of two or more other channels, where each channel is centered upon a carrier frequency, the apparatus comprising:
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processing means for identifying at least one set of carrier frequencies, the m-th order linear combination of which gives rise substantially to the carrier frequency of said test channel;
signal generators arranged to be tuned to respective ones of identified carrier frequencies of the at least one set to provide output signals to an input of a communication system under test; and
measuring means for measuring the output of said system under test to determine the inter-modulation interference at the carrier frequency of the test channel. - View Dependent Claims (10, 11)
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Specification