×

Passive time domain reflectometer for HFC network

  • US 9,414,126 B1
  • Filed: 03/09/2015
  • Issued: 08/09/2016
  • Est. Priority Date: 03/09/2015
  • Status: Active Grant
First Claim
Patent Images

1. A time domain reflectometry apparatus for detecting a linear impairment in a cable under test carrying RF signals including random and unwanted narrowband signals in a downstream direction, the linear impairment causing a reflection of the RF signals in an upstream direction, said apparatus comprising:

  • (a) an input, to be coupled to the cable under test at a test point upstream from the linear impairment, for receiving the RF signals and the reflection of the RF signals as a received signal, the received signal having a frequency spectrum including a plurality of sub-bands at a plurality of RF frequencies, respectively, each of the sub-bands containing a part of the received signal as a sub-band signal;

    (b) a tunable receiver, coupled to said input, for tuning to the plurality of sub-bands and receiving the sub-band signals, one sub-band at a time;

    (c) a filter, coupled to said tunable receiver, for filtering the sub-band signals, one sub-band at a time, said filter adapting to each sub-band signal to substantially remove any unwanted narrowband signal from the sub-band signal to produce a filtered sub-band signal;

    (d) an autocorrelation processor, coupled to said filter, for determining an autocorrelation function of each of the filtered sub-band signals, one sub-band at a time, to produce a plurality of sub-band autocorrelation functions;

    (e) an accumulator, coupled to said autocorrelation processor, for combining the plurality of sub-band autocorrelation functions together to form a combined autocorrelation function; and

    (f) detection means, coupled to said accumulator, for detecting the reflection of the RF signals from the combined autocorrelation function.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×