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Holtzman Inc., a manufacturer of test equipment for maintaining the cable upstream plant, has been issued a patent for measuring frequency response and dynamic range on a cable network.

The new technology allows cable plant frequency response to be measured as complex numbers, with both magnitude and group delay information, whereas conventional sweep equipment only obtains the magnitude portion of the frequency response. Group delay is a critical transmission parameter that may be caused by diplex filters or signal reflections. Group delay is especially important because it limits upstream data rates for DOCSIS 1.0 modems.

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