Test system for measuring frequency response and dynamic range on cable plant
First Claim
1. A system for testing a signal path to produce a complex frequency response of the signal path, said system comprising:
- a transmitter connected to a first location of the signal path, said transmitter for transmitting a predefined test signal, having a short duration, along the signal path;
a receiver connected to a second location of the signal path wherein the receiver receives the test signal as an impaired test signal;
a digital signal acquisition unit comprising a digital signal processor connected to the receiver, wherein the digital signal acquisition unit acquires the impaired test signal and processes the impaired test signal with an unimpaired test signal previously stored within the digital signal processor to produce the complex frequency response of the signal path between the first location and the second location.
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Accused Products
Abstract
A test system for measuring a frequency response of a signal path 148 by transmitting a short duration burst test signal 234 from a remote point 152, capturing an impaired burst test signal 432 on a digital signal acquisition unit 416, and analyzing the received signal by digitally processing it with an unimpaired burst test signal 434. A dynamic range test can also be performed with the same burst test signal by removing the energy in a part of the frequency band with a notch filter 232, and then increasing the power of the burst test signal level until non-linear distortion occurs. The distortion products will fill-in the notch, allowing the clipping threshold of the signal path to be measured. A burst trigger signal 244 generated by the transmitter device 201 causes a digital signal acquisition unit to acquire an impaired burst test signal.
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Citations
18 Claims
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1. A system for testing a signal path to produce a complex frequency response of the signal path, said system comprising:
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a transmitter connected to a first location of the signal path, said transmitter for transmitting a predefined test signal, having a short duration, along the signal path;
a receiver connected to a second location of the signal path wherein the receiver receives the test signal as an impaired test signal;
a digital signal acquisition unit comprising a digital signal processor connected to the receiver, wherein the digital signal acquisition unit acquires the impaired test signal and processes the impaired test signal with an unimpaired test signal previously stored within the digital signal processor to produce the complex frequency response of the signal path between the first location and the second location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system for testing a signal path to determine clipping of the signal path, said system comprising:
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a transmitter connected to a first location of the signal path, said transmitter for transmitting a predefined test signal, having a short duration, along the signal path;
a notch filter connected between the transmitter and the signal path wherein the notch filter removes a predefined portion of the test signal;
a receiver connected to a second location of the signal path wherein the receiver receives the test signal as an impaired test signal;
a digital signal acquisition unit comprising a digital signal processor connected to the receiver, wherein the digital signal acquisition unit acquires the impaired test signal and processes the impaired test signal to measure an amount of signal present in the predefined portion of the test signal removed by the notch filter wherein clipping occurs when a predetermined amount of signal is present is the predefined portion of the test signal removed by the notch filter.
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Specification