Symmetricom Patent Applications

PRECISE CLOCK SYNCHRONIZATION OVER OPTICAL FIBER

Granted: March 28, 2013
Application Number: 20130077964
A clock at a first network element that is connected to a second network element over first and second optical links that are physically distinct from each other is aligned using optical timing signals having different wavelengths. Transit delays between the first and second network elements may be determined using the same optical timing signals.

IMAGE COMPLEXITY COMPUTATION IN PACKET BASED VIDEO BROADCAST SYSTEMS

Granted: May 14, 2009
Application Number: 20090125291
A method to determine real time image complexity in video streaming, IPTV and broadcast applications using a statistical model representing channel bandwidth variation and image complexity that considers scene content changes. Available channel bandwidth is distributed unevenly among multiple video streams in proportion to bandwidth variation and image complexity of the broadcast video stream. The distribution of available channel bandwidth is determined based upon an image complexity…

SPATIAL AND TEMPORAL LOSS DETERMINATION IN PACKET BASED VIDEO BROADCAST SYSTEM IN AN ENCRYPTED ENVIRONMENT

Granted: June 12, 2008
Application Number: 20080137667
A method for determining spatial and temporal loss in a packet based video broadcast system in an encrypted environment involves measuring video coding layer information at an unencrypted head end of a video stream and network layer information at an encrypted downstream end of the same video stream. Video coding layer information is correlated with network layer information having a corresponding time stamp to compute the spatial and temporal loss. The video coding layer and network…

Fault detection for subscriber loop repeaters

Granted: March 6, 2003
Application Number: 20030045240
Systems and methods are described for fault detection for subscriber loop repeaters. A method includes monitoring an upstream signal on a digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and determining if a fault has occurred. An apparatus includes a digital subscriber loop fault detection system including: a receiver circuit that monitors an upstream signal on said digital subscriber loop for a fault detection signal that is…

Long subscriber loops using automatic gain control

Granted: August 8, 2002
Application Number: 20020105964
Systems and methods are described for long subscriber loops using automatic gain control. A method includes extending a digital subscriber loop including: producing an output signal from said first variable gain amplifier responsive to an input signal from said digital subscriber loop; monitoring a signal strength of said output signal; generating a gain control signal responsive to said signal strength; and controlling a gain of said variable gain amplifier responsive to said gain…

Subscriber loop repeater loopback for fault isolation

Granted: May 23, 2002
Application Number: 20020061058
Systems and methods are described for subscriber loop repeater loopback for fault isolation. A method includes obtaining a sample of a downstream signal conveyed along a signal path; performing an analysis of the sample; determining a presence or an absence of a fault in the signal path based on the analysis of the sample; indicating a presence or an absence of a fault in the signal path by transmitting a diagnostic signal to an upstream node; and isolating a location of the fault as a…

Asymmetric digital subscriber line methods suitable for long subscriber loops

Granted: January 3, 2002
Application Number: 20020001340
Systems and methods are described for asymmetric digital subscriber loops. A method includes utilizing a circuit having a first end and a second end, the circuit having a first amplification interface connecting the first end to the second end in a first direction, and a second amplification interface connecting the second end to the first end in a second direction; adapting the first amplification interface to provide a first gain adjustment as a function of a first attenuation of a…