Viavi Solutions Inc.

Acterna LLC

Adam D Gray

Daniel Keith Chappell

Loren R Eggert

David W Jones

Richard Earl Jones, Jr

Ching-Chang Liao

James P Bartlett

Richard J Cole

Kelly Watts

Brett Emsley

David Hering

Michael J Kunczt

Peter Sirota

A CMTS may instruct one or more cable modems to transmit an upstream test signal with a particular preamble (and or any other type of signature) in the upstream transmission bandwidth. The preamble may be within a significant band of the upstream transmission bandwidth. A leakage detection device may be brought in the vicinity of the cable network to listen for various signals. The leakage detection device may filter received signals to retain the portions thereof within a desired limited band and further filter the band-limited signals to reduce noise, e.g., removing the payload following the preamble. A correlation filter in the leakage detection device may compare the pattern in the band-limited filtered signal with a stored preamble. If there is a match, the leakage detection device may generate an indication that leakage is detected in the upstream transmission.

Upstream signal leakage detection in high-split cable network

Systems and methods for detecting leakage in a cable network system are disclosed. In at least some illustrative embodiments, a system may include a digital tagger operable to generate a digital tag including a chirp signal configured to be placed on a downstream signal path of the cable network system, and a cable network test instrument configured detect the digital tag in wireless signal data received from the cable network system when a point of ingress is presented in the cable network system. The network test instrument may be operable to provide a user-perceptible indication when the digital tag is detected to inform a technician or other user that a flaw in the cable network system is nearby.

Systems and methods for detecting leakage in a cable network system

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.

Cable network spectral measurement during upstream packet transmission

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.

Dual-port testing of a cable network

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.

Upstream signal quality monitoring

Growing community of inventors

Avon, IN, United States of America

Adam D Gray