Abstract: A method for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation of OUDP bursts includes: providing an apparatus for use in a patrol vehicle, the apparatus including a leak signal receiver coupled to a processor; measuring a duration of detected bursts to provide a plurality of burst durations; collecting a histogram of the burst durations during a measuring session to provide a duration histogram; and determining a presence of a leak based on a comparison of the duration histogram with expected durations of OUDP bursts. Systems for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation OUDP bursts, and other methods for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation OUDP bursts are also described.

Abstract: A method for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation of OUDP bursts includes: providing an apparatus for use in a patrol vehicle, the apparatus including a leak signal receiver coupled to a processor; measuring a duration of detected bursts to provide a plurality of burst durations; collecting a histogram of the burst durations during a measuring session to provide a duration histogram; and determining a presence of a leak based on a comparison of the duration histogram with expected durations of OUDP bursts. Systems for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation OUDP bursts, and other methods for monitoring leakage in an aeronautical band of a high split HFC by a detection and validation OUDP bursts are also described.

Abstract: A method for leakage detection in an aeronautical band for a high split HFC network includes: providing a vehicle borne leak detector configured to perform substantially simultaneous upstream and downstream leakage detection; and while traversing a hub containing any quantity of high split nodes, performing a substantially simultaneous upstream leakage detection and a downstream leakage detection at about a same frequency. A system for leakage detection in an aeronautical band for a high split HFC network is also described.

Abstract: A method for monitoring leakage in the aeronautical band of a high split HFC includes providing an apparatus for use in a patrol vehicle, the apparatus including a leak signal receiver coupled to a processor; setting a plurality of coefficients for an OUDP matched filter for a current location of the patrol vehicle; detecting peaks over a detection threshold at an output of the OUDP matched filter; and determining a presence of a leak based on a time stamp and a level of each detected peak. An upstream leak detection system is also described.

Abstract: Detecting PIM in a downstream signal, wherein the downstream signal is received from a cable plant via a subscriber network and an upstream signal is transmitted to the cable plant via the subscriber network. The upstream signal is transmitted in bursts during active intervals. PIM arises from an interaction between the upstream signal and a nonlinear component in the subscriber network and occurs in bursts corresponding to the upstream signal. The detection steps are: (a) identifying the potentially affected downstream signal from the upstream signal; (b) receiving the downstream signal during an active interval; (c) measuring a metric of the downstream signal to obtain an active value; (d) receiving the downstream signal during a quiet interval; (e) measuring the metric of the downstream signal to obtain a quiet value; (f) comparing active and quiet values; and (g) determining whether PIM distortion has been detected based on the comparison.

Abstract: A test equipment module and method of communicating maintenance data in a cable system is disclosed. The module comprises a receiver, a measurement system, a pilot generator, and a signal encoder. The receiver receives downstream signals from a host communication network. The measurement system determines a maintenance parameter value associated with the downstream signals. The pilot generator generates a pilot within the downstream frequency band, and a signal encoder encodes the pilot with the maintenance parameter value. The pilot generator adds the encoded pilot to the downstream signals in the communication network, such that a cable modem in the network can receive the encoded pilot and generate a spectrum that includes the encoded pilot. A PNM server receives the spectrum from the cable modem and determines the maintenance parameter value from the spectrum.

Abstract: A test equipment module and method of communicating maintenance data in a cable system is disclosed. The module comprises a receiver, a measurement system, a pilot generator, and a signal encoder. The receiver receives downstream signals from a host communication network. The measurement system determines a maintenance parameter value associated with the downstream signals. The pilot generator generates a pilot within the downstream frequency band, and a signal encoder encodes the pilot with the maintenance parameter value. The pilot generator adds the encoded pilot to the downstream signals in the communication network, such that a cable modem in the network can receive the encoded pilot and generate a spectrum that includes the encoded pilot. A PNM server receives the spectrum from the cable modem and determines the maintenance parameter value from the spectrum.

Abstract: A TDR for locating impairments in an HFC network is claimed. The network carries burst signals in an upstream band during burst intervals. The TDR comprises a transmitter, receiver, level detector, controller, accumulator, and probe detector. The transmitter transmits probe signals to the impairment, causing a reflection of the probe signals. Each probe signal is in the upstream band and has a bandwidth extending the width of the upstream band. The receiver receives the reflected probe signals during receiving intervals, and receives the burst signals during receiving intervals that overlap burst intervals. The level detector measures a level of the signals received during each receiving interval. The controller determines which of the receiving intervals are free of burst signals, based on the level measurement. The accumulator accumulates reflected probe signals received during intervals free of burst signals.

Abstract: The invention involves using Doppler shift to locate a leak of a signal from an HFC network. The leaked signal includes a component having a nominal frequency. The invention comprises: (a) moving along a drive route in the area of the network; (b) recording a speed at a number of drive-route points along the drive route; (c) at each point, receiving the component at a received frequency; (d) for each point, measuring the received frequency; (e) for each point, determining a measured Doppler shift from a difference between the received and nominal frequencies; (f) estimating a zero Doppler shift and a zero Doppler shift point based on the measured Doppler shifts; and (g) estimating the leak location based on the estimated zero Doppler shift point.

Abstract: Detection of OFDM signals leaking from an HFC network with CCAP architecture is presented. Leak detection includes creating signatures of the OFDM signals and using them in an adaptive coherent cross-correlation processing method. The signature is created at a server and then transmitted to a field leakage detector via a wireless network. The server constructs signatures based on modulation and other parameters of the OFDM signal. The detector adaptively selects valid signatures depending on the location of the detector. A cross-correlation receiver samples the OFDM leakage signal in synchronism with a GPS clock and an OFDM master clock at a CMTS. Capture of the OFDM leakage signal in the detector is synchronized with the symbol rate and timestamp of the OFMD signal to achieve time delay measurements of the leak signal at different locations of the detector. Then, the leak is located using known TDOA or network database methods.

Abstract: Detecting a leak of an OFDM signal from an HFC network, where the HFC network extends over a network area. The OFDM signal includes a first continuous pilot subcarrier having a first harmonic. The first harmonic is defined by a pre-determined first frequency. The method or apparatus comprises the steps of or means for: (a) moving a leakage detector through the network area; (b) tuning the leakage detector to receive the first harmonic of the OFDM signal, based on the pre-determined first frequency of the first harmonic; (c) with the leakage detector, receiving over-the-air, at a received first frequency, the first harmonic of the OFDM signal leaked from the HFC network; and (d) with the leakage detector, detecting the first harmonic received in step (c), whereby the leak of the OFDM signal is detected based on the detection of the first harmonic.

Abstract: A apparatus or method for detecting CPD in an HFC network, comprising: (a) acquiring digital RF downstream signals from a CMTS or CM; (b) emulating even and odd order IM distortion products from the downstream signals; (c) acquiring RF upstream signals from the CMTS during a quiet period; (d) cross-correlating the RF upstream signals with the emulated even and odd order IM products to produce even and odd order cross-correlation functions, respectively; (e) accumulating, separately, a multiplicity of even and odd order cross-correlation functions; (f) calculating even and odd order cross-correlation envelopes from the accumulated even and odd order cross-correlation functions, respectively; and (g) detecting a CPD source from either or both of the even and odd order cross-correlation envelopes by the presence of a peak in either or both of the envelopes.

Abstract: The invention involves using Doppler shift to locate a leak of a signal from an HFC network. The leaked signal includes a component having a nominal frequency. The invention comprises: (a) moving along a drive route in the area of the network; (b) recording a speed at a number of drive-route points along the drive route; (c) at each point, receiving the component at a received frequency; (d) for each point, measuring the received frequency; (e) for each point, determining a measured Doppler shift from a difference between the received and nominal frequencies; (f) estimating a zero Doppler shift and a zero Doppler shift point based on the measured Doppler shifts; and (g) estimating the leak location based on the estimated zero Doppler shift point.

Abstract: A method of detecting a digital leakage signal originating from a leak in a coaxial cable portion of an HFC network. The network has a transmission end from which a digital signal is transmitted to the coaxial cable portion. The digital signal is emitted into free space from the leak to produce the leakage signal. The method comprises: (a) producing a first set of samples representing the digital signal; (b) transmitting the first set of samples to a leakage detector; (c) moving the leakage detector to a detection point in the vicinity of the network; (d) receiving the leakage signal from the leak; (e) sampling the leakage signal to produce a second set of samples; and (f) performing a cross-correlation of the first set of samples with the second set of samples, to produce a cross-correlation function having a peak, whereby the leakage signal is detected from the peak.

Abstract: A method of detecting a digital leakage signal originating from a leak in a coaxial cable portion of an HFC network. The network has a transmission end from which a digital signal is transmitted to the coaxial cable portion. The digital signal is emitted into free space from the leak to produce the leakage signal. The method comprises: (a) producing a first set of samples representing the digital signal; (b) transmitting the first set of samples to a leakage detector; (c) moving the leakage detector to a detection point in the vicinity of the network; (d) receiving the leakage signal from the leak; (e) sampling the leakage signal to produce a second set of samples; and (f) performing a cross-correlation of the first set of samples with the second set of samples, to produce a cross-correlation function having a peak, whereby the leakage signal is detected from the peak.

Abstract: A apparatus or method for detecting CPD in an HFC network, comprising: (a) acquiring digital RF downstream signals from a CMTS or CM; (b) emulating even and odd order IM distortion products from the downstream signals; (c) acquiring RF upstream signals from the CMTS during a quiet period; (d) cross-correlating the RF upstream signals with the emulated even and odd order IM products to produce even and odd order cross-correlation functions, respectively; (e) accumulating, separately, a multiplicity of even and odd order cross-correlation functions; (f) calculating even and odd order cross-correlation envelopes from the accumulated even and odd order cross-correlation functions, respectively; and (g) detecting a CPD source from either or both of the even and odd order cross-correlation envelopes by the presence of a peak in either or both of the envelopes.

Abstract: A method or apparatus of identifying for repair a signal leak in an HFC network, wherein a base transceiver station in the vicinity of the HFC network transmits a BTS signal over-the-air. The method comprises or apparatus performs the steps of: (a) identifying a location of the signal leak; (b) in the vicinity of the signal leak, detecting the BTS signal; (c) determining a level of the BTS signal; (d) defining a threshold level; (e) with the use of a processor, determining whether the level of the BTS signal meets or exceeds the threshold level; and (f) indicating for repair the signal leak if the level of the BTS signal meets or exceeds the threshold level.

Abstract: Detecting a linear impairment in a cable under test by using a random signal transmitted down the cable. The impairment causes a reflected signal to be combined with the random signal. The combined signal extends over a plurality of sub-bands. A method and apparatus perform the steps of: (a) receiving the combined signal from a test point upstream from the impairment; (b) tuning to each sub-band and receiving a part of the combined signal within each sub-band; (c) determining an autocorrelation function of each part of the combined signal of each sub-band, to produce a plurality of autocorrelation functions; (d) combining the autocorrelation functions to form a combined function; (e) detecting the reflected signal from the combined function; and (f) determining, from the combined function, a time delay associated with the reflected signal and the distance from the test point to the impairment.

Abstract: A method or apparatus of identifying for repair a signal leak in an HFC network, wherein a base transceiver station in the vicinity of the HFC network transmits a BTS signal over-the-air. The method comprises or apparatus performs the steps of: (a) identifying a location of the signal leak; (b) in the vicinity of the signal leak, detecting the BTS signal; (c) determining a level of the BTS signal; (d) defining a threshold level; (e) with the use of a processor, determining whether the level of the BTS signal meets or exceeds the threshold level; and (f) indicating for repair the signal leak if the level of the BTS signal meets or exceeds the threshold level.

Abstract: A handheld leakage detector for finding digital signal leaks in a HFC network, comprises a radio receiver, a leakage receiver, leakage sampler, a correlator, and a display. The radio receiver receives samples of the digital signal taken from the HFC network, called “reference samples.” The leakage receiver receives a leakage signal, which is a leaked version of the digital signal from the HFC network. The leakage sampler samples the leakage signal to form leakage samples. The correlator performs a cross-correlation of the reference samples and the leakage samples, to produce a correlation function. An optimizable value is determined from the correlation function. The value generally becomes more optimized as the detector approaches the leak. The leak is sought by iteratively changing the position of the detector until the value becomes substantially optimized or the leak is found.