Abstract: A cable network test instrument for isolating a source of noise in a cable network system is disclosed.

Abstract: Unlike conventional methods and systems for locating ingress, which only monitor the upstream path, a method and system of locating ingress by monitoring the downstream path is provided. A test system measures the signal quality in the upstream path and in dependence upon a noise level being above a predetermined limit, polls a plurality of terminal equipment devices to return a downstream signal quality measurement. The test instrument analyzes the downstream signal quality measurements to locate an ingress source contributing to the noise.

Abstract: A cable network test instrument for isolating a source of noise in a cable network system is disclosed.

Abstract: A diagnostic data acquisition system for analyzing impairments in a QAM digital communication system is triggered by diagnostic data generated by a QAM demodulator when demodulating a QAM signal. Upon triggering, the data acquisition system can capture the diagnostic data used for triggering, and/or some other diagnostic data. The captured data may be stored for subsequent analysis to determine a probable cause of the impairment.

Abstract: Systems and methods for quantifying the suitability of a coax network segment to support MoCA communications, comprising: transmitting a test signal associated with MoCA communications through the segment's first end; receiving the test signal through the segment's second end; determining a response function; determining a channel degradation reference based on the highest power level of the response function and a predetermined reference; calculating subcarrier degradation for each MoCA subcarrier, in accordance with the difference between the channel degradation reference and the subcarrier response function; and quantifying the suitability of the segment to support MoCA communications from the first end to the second end in accordance with the subcarrier degradation of all subcarriers in the response function.

Abstract: The present invention provides a test device and a method enabling automatic detection of an imbalance in a power level of a channel. The test device includes a tuner, a power-level measurement system, and an evaluation unit. According to the method, a test channel is selected from a plurality of channels, by means of the tuner. A power level of the test channel and a total power level of the plurality of channels are measured, by means of the power-level measurement system. A ratio of the total power level of the plurality of channels to the power level of the test channel is then evaluated, by means of the evaluation unit, to detect an imbalance in a power level of the test channel.

Abstract: Unlike conventional methods and systems for locating ingress, which only monitor the upstream path, a method and system of locating ingress by monitoring the downstream path is provided. A test system measures the signal quality in the upstream path and in dependence upon a noise level being above a predetermined limit, polls a plurality of terminal equipment devices to return a downstream signal quality measurement. The test instrument analyzes the downstream signal quality measurements to locate an ingress source contributing to the noise.

Abstract: The invention relates to measurement-capable cable modems for cable networks. Idle receivers and transmitters of a cable modem are used to perform upstream and downstream measurements on DOCSIS and non-DOCSIS digital and analog TV channels without disrupting customer services. A currently idle receiver is tuned to a target downstream channel under directions of a modem measurement controller, and is queried by the measurement controller to perform a measurement as specified by a measurement plan. A currently idle transmitter is tuned to a target upstream channel to transmit a test signal that is received by an upstream measurement system. Measurements are communicated to a central measurement controller, for example located at the headend, which collects measurements from a plurality of cable modems and the upstream measurement system. The resulting monitoring system performs cable network wide monitoring using existing cable modems without requiring additional monitoring devices.

Abstract: The invention relates to a method for measuring Hum on a digital QAM carrier using a testing device for testing digital TV signals including a QAM demodulator therein, and to a testing device implementing the method. A controller is used to sample a register associated with a final AGC stage in a QAM demodulator, and to process the collected register values to obtain one or more Hum characteristics. In one embodiment, a circular buffer is used to collect aligned sequences of AGC samples that have a pre-determined feature of time-domain Hum at a specified position therein. The aligned AGC sequences are then correlated to assess causes of Hum.

Abstract: Systems and methods for quantifying the suitability of a coax network segment to support MoCA communications, comprising: transmitting a test signal associated with MoCA communications through the segment's first end; receiving the test signal through the segment's second end; determining a response function; determining a channel degradation reference based on the highest power level of the response function and a predetermined reference; calculating subcarrier degradation for each MoCA subcarrier, in accordance with the difference between the channel degradation reference and the subcarrier response function; and quantifying the suitability of the segment to support MoCA communications from the first end to the second end in accordance with the subcarrier degradation of all subcarriers in the response function.

Abstract: A diagnostic data acquisition system for analyzing impairments in a QAM digital communication system is triggered by diagnostic data generated by a QAM demodulator when demodulating a QAM signal. Upon triggering, the data acquisition system can capture the diagnostic data used for triggering, and/or some other diagnostic data. The captured data may be stored for subsequent analysis to determine a probable cause of the impairment.

Abstract: A method and apparatus are provided for detecting network impairments through tilt-normalized measurement data, the method including: collecting data for a network signal; computing a best-fit tilt for the collected data; performing tilt-normalization of the collected data responsive to the computed best-fit tilt; and determining whether the tilt-normalized data crosses a threshold, and if so, pattern matching the tilt-normalized data to detect a network impairment; and the apparatus including: an input unit for collecting data from a network signal; a tilt unit connected to the input unit for computing a best-fit tilt for the collected data and performing tilt-normalization of the collected data responsive to the computed best-fit tilt; and a pattern matching unit connected to the tilt unit for determining whether the tilt-normalized data crosses a threshold, and if so, pattern matching the tilt-normalized data to detect at least one network impairment.

Abstract: A method and apparatus are provided for testing susceptibility of a receiver to intermodulation distortion of a digital channel, the method including selecting a first digital channel from channels in a composite signal, determining a first power measurement from the first digital channel, determining a total power measurement from other channels in the composite signal, and determining susceptibility of the first digital channel to intermodulation distortion by comparing the first power measurement and the total power measurement with intermodulation distortion characteristics of the receiver.

Abstract: The invention relates to a method for measuring Hum on a digital QAM carrier using a testing device for testing digital TV signals including a QAM demodulator therein, and to a testing device implementing the method. A controller is used to sample a register associated with a final AGC stage in a QAM demodulator, and to process the collected register values to obtain one or more Hum characteristics. In one embodiment, a circular buffer is used to collect aligned sequences of AGC samples that have a pre-determined feature of time-domain Hum at a specified position therein. The aligned AGC sequences are then correlated to assess causes of Hum.

Abstract: The invention relates to measurement-capable cable modems for cable networks. Idle receivers and transmitters of a cable modem are used to perform upstream and downstream measurements on DOCSIS and non-DOCSIS digital and analog TV channels without disrupting customer services. A currently idle receiver is tuned to a target downstream channel under directions of a modem measurement controller, and is queried by the measurement controller to perform a measurement as specified by a measurement plan. A currently idle transmitter is tuned to a target upstream channel to transmit a test signal that is received by an upstream measurement system. Measurements are communicated to a central measurement controller, for example located at the headend, which collects measurements from a plurality of cable modems and the upstream measurement system. The resulting monitoring system performs cable network wide monitoring using existing cable modems without requiring additional monitoring devices.

Abstract: The invention relates to a method for measuring Hum on a digital QAM carrier using a testing device for testing digital TV signals including a QAM demodulator therein, and to a testing device implementing the method. A micro-controller is used to sample a register associated with an AGC circuit in the QAM demodulator, and to process the collected register values to obtain one or more Hum characteristics.

Abstract: The present invention relates to a system for calculating a digital quality index (DQI), which provides a rating on a predetermined scale, indicative of the impairments in a received quadrature amplitude modulated (QAM) signal in a CATV cable system. The DQI system utilizes bit error rates prior to and after forward error correction to calculate the DQI value. To increase the calculation rate, the bit error rates can be estimated using voltage errors, signal to noise ratios and/or average corner error metrics.

Abstract: The present invention provides a test device and a method enabling automatic detection of an imbalance in a power level of a channel. The test device includes a tuner, a power-level measurement system, and an evaluation unit. According to the method, a test channel is selected from a plurality of channels, by means of the tuner. A power level of the test channel and a total power level of the plurality of channels are measured, by means of the power-level measurement system. A ratio of the total power level of the plurality of channels to the power level of the test channel is then evaluated, by means of the evaluation unit, to detect an imbalance in a power level of the test channel.

Abstract: A method and apparatus are provided for detecting network impairments through tilt-normalized measurement data, the method including: collecting data for a network signal; computing a best-fit tilt for the collected data; performing tilt-normalization of the collected data responsive to the computed best-fit tilt; and determining whether the tilt-normalized data crosses a threshold, and if so, pattern matching the tilt-normalized data to detect a network impairment; and the apparatus including: an input unit for collecting data from a network signal; a tilt unit connected to the input unit for computing a best-fit tilt for the collected data and performing tilt-normalization of the collected data responsive to the computed best-fit tilt; and a pattern matching unit connected to the tilt unit for determining whether the tilt-normalized data crosses a threshold, and if so, pattern matching the tilt-normalized data to detect at least one network impairment.

Abstract: The invention relates to a method for measuring Hum on a digital QAM carrier using a testing device for testing digital TV signals including a QAM demodulator therein, and to a testing device implementing the method. A micro-controller is used to sample a register associated with an AGC circuit in the QAM demodulator, and to process the collected register values to obtain one or more Hum characteristics.