Patent application number | Description | Published |
20080298270 | Upstream Signal Quality Monitoring - The problem is that a measurement of the average signal quality (average modulation error ratio), does not identify poor quality signals that may be originating from an individual cable modem. The device of the present invention displays the modulation error ratio (MER) for each packet received. Since the media access control (MAC) address is associated with a packet received from an individual cable modem, a graph displaying the MER for each packet received is also displaying the MER for signals from the individual cable modems. Thus a technician viewing the display will be able to identify whether a low MER is a result of an impairment in the network or the from an individual cable modem. | 12-04-2008 |
20090086804 | Automatic Gain Control Stress Measurement For Digital Carriers - The testing equipment of the present invention calculates a single “AGC stress” value, which provides an indication of the stability of the level of a digital carrier based on the change in gain required to stabilize the power of an incoming cable signal over time. Ideally the AGC stress value is rated on a scale, e.g. 1 to 10 or 0 to 5, and is fed into the DQI measurement system as a new data model. | 04-02-2009 |
20090096665 | Method For Locating Cable Impairments - Methods are disclosed for identifying and locating points of impairment in a cable plant, such as that used for cable television (CATV). The methods utilize both known characteristics of signals as well as propagation times in free space and within the cable in conjunction with accurate determination of locations at which measurements are taken. The methods can be applied to both RF cable leaks as well as points of ingress of interference. | 04-16-2009 |
20090185037 | MEASURING HUM IN A DIGITAL TV SIGNAL - 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. | 07-23-2009 |
20090268034 | MEASURING THE FREQUENCY RESPONSE OF A CATV NETWORK - An apparatus and method for frequency sweeping a CATV network, suitable for an upstream path frequency sweeping, is presented. A narrowband test signal is injected into the network by a generator coupled to a cable modem during a time interval allocated by the head end for the cable modem to transmit a modulated digital signal. The amplitude of the test signal is lower than the amplitude of the modulated digital signal, so as not to impair reception of said digital signal at the head end. The frequency of the test signal is swept, and the amplitude of the received test signal is measured. A telemetry or a digital signal transmission is used to communicated the values of the amplitude of the test signals between the injection and the measurement locations of the network. | 10-29-2009 |
20100070228 | DETECTING NONLINEARITY IN A CABLE PLANT AND DETERMINING A CABLE LENGTH TO A SOURCE OF THE NONLINEARITY - An apparatus and a method for detecting a nonlinearity in a cable plant and for determining cable length to a source of the nonlinearity are disclosed. Upstream signal peaks are detected by averaging upstream signal waveforms. The upstream signal peaks are generated at the source of the nonlinearity from naturally occurring downstream signal peaks propagating in the cable plant. The downstream signal peaks occur due to constructive superposition of the downstream channel signals. Acquisition of the upstream signal waveforms is triggered by the downstream signal peaks. The cable length to the source of nonlinearity is determined from a time delay between the downstream signal peaks and the upstream signal peaks. | 03-18-2010 |
20100309805 | TESTING UPSTREAM CABLE CHANNELS - In order to measure the performance of a DOCSIS upstream channel as well as to locate impairments, a special test signal is transmitted in a time slot of the upstream channel by a test instrument positioned anywhere within the CATV plant. A second test instrument, located at the termination point of the upstream plant, then detects, recovers, and processes the test signal in order to complete the measurement. The typical methods used to detect and recover bursted signals within a DOCSIS upstream channel use precise timing information transmitted in a corresponding DOCSIS downstream channel. Unfortunately, the downstream channel and thus the precise timing information are not always available to the secondary test instrument. The present invention also describes an apparatus and method for detecting a bursted test signal without the use of the DOCSIS upstream channel timing. | 12-09-2010 |
20120074952 | HOME NETWORK CHARACTERIZATION METHOD AND SYSTEM - A method of characterizing a wiring network is implemented in a system which includes a test controller and at least two probes. On commands from the test controller, at least one of the probes changes its impedance between the nominal impedance of the wiring network and a mismatch impedance. Reflectometry measurements are performed before and after of switching the impedance of the second probe. At the first probe, an RF signal is generated and a reflected signal is measured. Then, the impedance of the second probe is changed, and again an RF signal is generated and a reflected signal is measured at the first probe. Additionally, a frequency response may be measured at the second probe. The results of the measurements are used for characterization of a transmission line between the first and second probes | 03-29-2012 |
20130194936 | MOCA QUALITY INDEX MEASUREMENT SYSTEM FOR QUALIFYING HOME NETWORKS - 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. | 08-01-2013 |
20140082686 | CHARACTERIZING INGRESS NOISE - Methods and devices for characterization of repetitious noise in cable networks are disclosed. A frequency band of interest is identified, a time trace of a signal parameter within the frequency band is obtained, and an autocorrelation of the time trace is computed to detect repetitious noise. The repetition frequency can serve as an indicator of the noise source type, and thus it can assist in noise segmentation. | 03-20-2014 |
20150009795 | CABLE NETWORK SPECTRAL MEASUREMENT DURING UPSTREAM PACKET TRANSMISSION - Apparatus and method are provided for obtaining an upstream signal spectrum as it was during a time of transmission of a received upstream data packet. The apparatus includes an analog-to-digital converter (ADC), a packet detector coupled to ADC, and a spectrum calculation unit coupled to the ADC and the packet detector. In operation, the spectrum calculation unit computes a spectrum of the digitized upstream signal as it was between the start and end times of the first packet. As a result, the obtained spectrum is representative of a condition of the transmission path during transmission of the upstream data packet. | 01-08-2015 |
20150020129 | DUAL-PORT TESTING OF A CABLE NETWORK - A dual-port testing apparatus is provided for testing a cable network at two test points. The testing may comprise demodulation of a same data packet at the test points, decoding the data packet, performing spectral analysis of the signal, etc. Testing results may be correlated with one another, both visually and by using pre-defined test metrics comprising a weighted sum of demodulation and decoding parameters such as modulation extinction ratio and a codeword error. | 01-15-2015 |