Non-disruptive sweep measurement using coherent detection
First Claim
1. A method for obtaining a frequency response of a cable network between first and second spaced apart points thereof, the method comprising:
- (a) inserting a multi-frequency test signal into the cable network with a transmitter at the first point at a power level below that of active signals on the cable network, so as to substantially not disrupt the transmission of the active signals; and
(b) coherently detecting power readings of the multi-frequency test signal with a receiver at the second point of the cable network; and
c) generating the frequency response of the cable network from results of step b).
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Accused Products
Abstract
Non-disruptive sweep measurements using low power coherent signals overcome the limitations of prior art frequency response systems for cable networks. Modulated or unmodulated, e.g. continuous wave (CW), test signals are transmitted into the network at a first or input point (input point is in the head end for forward sweep; input point is in the field for reverse sweep). The test signals are transmitted continuously at multiple frequencies, so as a composite they form a wideband, OFDM-like (orthogonal frequency-division multiplexing) waveform. A receiver at a second or output point generates power reading measurements, from which the frequency response of the network is produced.
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Citations
21 Claims
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1. A method for obtaining a frequency response of a cable network between first and second spaced apart points thereof, the method comprising:
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(a) inserting a multi-frequency test signal into the cable network with a transmitter at the first point at a power level below that of active signals on the cable network, so as to substantially not disrupt the transmission of the active signals; and (b) coherently detecting power readings of the multi-frequency test signal with a receiver at the second point of the cable network; and c) generating the frequency response of the cable network from results of step b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for obtaining a frequency response of a cable network between first and second spaced apart points thereof, the apparatus comprising:
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a transmitter configured to provide a multi-frequency test signal to the cable network at the first point thereof at a power level below that of active signals on the cable network, so as to substantially not disrupt the transmission of the active signals sharing at least one frequency with the multi-frequency test signal; and a coherent receiver configured to coherently detect power readings of the multi-frequency test signal at the second point of the cable network.
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Specification