Abstract: Time domain duplex (TDD) is contemplated, including controlling switches and/or amplifiers to facilitate signaling between a network and a plurality of end stations (ESs) according to a TDD control strategy. The TDD control strategy may be characterized by preventing simultaneous upstream and downstream communication between the network and one or more of the ESs over a particular frequency band. The TDD control strategy may be limited to a particular frequency range such that signaling outside of frequency range may be simultaneously communicated upstream and downstream.

Abstract: Signal interleaving of multiple signals, such as those associated with transmissions within a high-speed data network from subscribers to the Internet or other locations, is contemplated. The transmitted signals may be interleaved by adding signals from one subscriber with those transmitted from another subscriber. The transmitted signals may include spectral holes such that when one or more spectral holes of the signal sent from one subscriber add together with signals from another subscriber, or other simultaneously transmitting device, it fills spectral holes in a manner that maximizes transmission capabilities.

Abstract: The scene is illuminated by light pulses at higher intensities at predetermined times than at times between the predetermined times. Images of the scene are captured at the predetermined times to provide a sequence of anchor frames in a stream of images, and images of the scene are captured at times between said predetermined times to provide non-anchor frames in the stream. The anchor and non-anchor frames are then compressed and processed to produce video with greater compression and reduced noise artifacts. The scene is illuminated by light pulses with wavelengths outside the visible range. Upon sensing motion, the scene is illuminated by light pulses to provide video in the visible wavelength range. The scene is illuminated by a sequence of light pulses of different wavelengths when motion is detected in the scene. Different wavelength images of the scene are combined to provide higher resolution colored images without color filtering.

Abstract: A duplex communication system having gate-implemented noise management is contemplated. The system may include a gate or other device sufficiently operable to facilitate managing upstream and downstream signaling so as to ameliorate noise funneling between communicating endpoints by selectively controlling communication paths through which noise may be propagated. Optionally, the system may be operably configured to facilitate this type of gate-implemented noise management for time domain duplex (TDD) and frequency domain duplex (FDD) communications.

Abstract: Disclosed is an apparatus and method for increasing the error correction capabilities of a receiver circuit that receives a data stream of encoded data symbols that are encoded with a linear block code. Analog and digital comparator circuits are used to detect laser clipping or analog to digital converter overloading. Corrupted symbols are detected by comparing in-phase and/or quadrature phase baseband signals with pre-determined threshold limits that indicate that the in-phase and quadrature phase signals have exceeded the normal signal trajectory of an unimpaired signal. Corrupted symbols may also be detected by determining that the laser has been clipped. Corrupted symbols are marked for erasure prior to decoding and error correction. Erasure of corrupted signals increases the error correction capabilities of the decoder circuit.

Abstract: The upstream performance characteristics of a network are measured by looping a signal through both the downstream and upstream paths of the network. Test equipment may be located at a headend of the network and configured to transmit a signal downstream to a remotely located loopback device that redirects the signal in the upstream path to the test equipment. The upstream characteristics may be predominant in the analysis of the return signal because the downstream path may be relatively free from noise.

Abstract: Disclosed is an apparatus and method for increasing the error correction capabilities of a receiver circuit that receives a data stream of encoded data symbols that are encoded with a linear block code. Analog and digital comparator circuits are used to detect laser clipping or analog to digital converter overloading. Corrupted symbols are detected by comparing in-phase and/or quadrature phase baseband signals with pre-determined threshold limits that indicate that the in-phase and quadrature phase signals have exceeded the normal signal trajectory of an unimpaired signal. Corrupted symbols may also be detected by determining that the laser has been clipped. Corrupted symbols are marked for erasure prior to decoding and error correction. Erasure of corrupted signals increases the error correction capabilities of the decoder circuit.

Abstract: The upstream performance characteristics of a network are measured by looping a signal through both the downstream and upstream paths of the network. Test equipment may be located at a headend of the network and configured to transmit a signal downstream to a remotely located loopback device that redirects the signal in the upstream path to the test equipment. The upstream characteristics may be predominant in the analysis of the return signal because the downstream path may be relatively free from noise.

Abstract: A system for determining a composite signal level at which a signal path begins to generate non-linear distortion. A reference test signal, which is preferably a short-duration burst of repeatable broadband energy, is passed through the signal path and received on a digital signal acquisition unit. An impaired received reference test signal is comprised of the transmitted reference test signal, linear distortion components, and non-linear distortion components. The impaired received reference test signal is digitally processed to reveal the non-linear distortion components. The impaired received reference test signal may be processed with a stored reference test signal to find a time-domain impulse response from which the uncorrelated distortion energy can be measured.

Abstract: According to the invention, waste materials containing amido-carboxylic acid esters, which are generated during the preparation of phenyl ester salts, can be converted into amido-carboxylic acids. The recovered amido-carboxylic acid is then useful in the preparation of additional phenyl ester salt by the original preparation process or other processes known in the art. The process of the invention combines a waste material containing amido-carboxylic acid esters with an aqueous solution of a strong acid having a pH less than about 1 to form a mixture. The process heats the mixture to a temperature of at least 90° C. and maintains the mixture at that temperature for a time sufficient to hydrolyze the amido-carboxylic acid esters to amido-carboxylic acids. Sufficient base is the added to adjust the pH of the mixture to greater than about 2. The mixture is then maintained at a temperature of at least 80° C.

Abstract: Disclosed is a system and method that allows a plurality of modems to transfer data simultaneously within a single frequency channel of a cable. Each modem is assigned a frequency band within the frequency channel. A receiving unit captures a block of data from the frequency channel, processes the data and separates data for each frequency band. Data for each frequency band is demodulated to recover encoded data. The receiving unit may process a plurality of channels. Simultaneous transfer of data by a plurality of modems within a single channel may be employed to carry a plurality of simultaneous lower-speed data streams such as voice conversations. The frequency of a band employed for voice information transfer may be reassigned if the band is scheduled for other transmission or exhibits an error rate greater than or equal to a predetermined value.

Abstract: According to the invention, waste materials containing amido-carboxylic acid esters, which are generated during the preparation of phenyl ester salts, can be converted into amido-carboxylic acids. The recovered amido-carboxylic acid is then useful in the preparation of additional phenyl ester salt by the original preparation process or other processes known in the art. The process of the invention combines a waste material containing amido-carboxylic acid esters with an aqueous solution of a strong acid having a pH less than about 1 to form a mixture. The process heats the mixture to a temperature of at least 90° C. and maintains the mixture at that temperature for a time sufficient to hydrolyze the amido-carboxylic acid esters to amido-carboxylic acids. Sufficient base is the added to adjust the pH of the mixture to greater than about 2. The mixture is then maintained at a temperature of at least 80° C.

Abstract: A test system for measuring a frequency response of a signal path 148 by transmitting a short duration burst test signal 234 from a remote point 152, capturing an impaired burst test signal 432 on a digital signal acquisition unit 416, and analyzing the received signal by digitally processing it with an unimpaired burst test signal 434. A dynamic range test can also be performed with the same burst test signal by removing the energy in a part of the frequency band with a notch filter 232, and then increasing the power of the burst test signal level until non-linear distortion occurs. The distortion products will fill-in the notch, allowing the clipping threshold of the signal path to be measured. A burst trigger signal 244 generated by the transmitter device 201 causes a digital signal acquisition unit to acquire an impaired burst test signal.

Abstract: A method for constructing trusses includes providing a plurality of truss tables that includes channel that do not unduly deform or bend during truss construction. Each table includes a support frame and a plurality of substantially horizontally-disposed elongate steel panels. Each panel has an upper surface, a lower surface, and opposing lateral edge portions. The panels are positioned so that their respective upper surfaces are substantially coplanar and so that one of the lateral edge portions of each panel is in adjacent, non-contacting relationship with one of the lateral edge portions of an adjacent panel, such that a gap is defined between the adjacent lateral edge portions of adjacent panels. The panels are supported from underneath by the frame, and each of the gaps is substantially parallel with each of the other gaps.

Abstract: A test (600) system for characterizing the nature and the severity of the impairments affecting a radio frequency signal path (148) which may be an upstream or a downstream channel in a cable system. Testing is done by monitoring the output of an unused signal path (614) with a filter (608) and a totaling counter (612). The filter passes impairment energy from the signal path to the counter in a frequency band of interest, thereby increasing the count value on the counter. The bandpass filter limits the ability of impairments or signals from other frequency bands to increase the counter's count value. The counter's input threshold voltage level (404) is set to trigger on impairments that are sufficiently strong to cause data errors. The count value may be used to determine the time duration of an impairment by dividing the count accumulated in one second by the center frequency of the filter.

Abstract: A system that utilizes a reference signal for testing signal paths for complex frequency response (linear distortion), and non-linear distortion. This reference signal, which is also known as a ghost canceling reference signal or a training waveform, has excellent properties for channel characterization. The reference signal is a waveform that operates for a major time interval that is subdivided into multiple minor time intervals. During each minor time interval, a sine wave oscillates at a constant angular velocity or frequency. The sine wave frequency may take uniform steps between the minor time intervals, or it may skip a group of frequencies. The phase of the waveform may optionally be continuous between the end of one minor time interval and the start of the next minor time interval. This waveform is generated by loading the time sample values from a digital memory into a digital to analog converter (D-A), or by rapidly reprogramming a numerically-controlled oscillator.

Abstract: A digital transmission system that provides high immunity to rapidly changing multipath distortion by sending a normal data block followed by a reciprocal data block with the same random data in an inverted form. The second block of data is comprised of frequency components whose coefficients are the reciprocal of the frequency coefficients found in the equivalent terms in the first block. At the receive site, both blocks are received and transformed into the frequency domain The frequency coefficients of the second block are divided by the corresponding frequency coefficient in the first block using complex arithmetic. The square root is taken on the product, yielding a de-ghosted normal block. If any of the frequency coefficients of the first block of data are zero, creating the reciprocal will involve division by zero. This problem Is remedied by using a modulation system such as orthogonal frequency division multiplexing (OFDM) that can maintain control over coefficient values at all frequencies.

Abstract: A system for determining if there is a break in the shield or a compromise in the shielding effectiveness of coaxial cable plant by inducing a reference test signal onto the sheath or outer conductor of a coaxial cable. Concurrent testing is done with a digital sampling receiver for the presence of some of the induced reference signal on the inner or center conductor of the cable. The test current may be introduced directly onto the coax's sheath by magnetically coupling with a split ferrite core, or it may be applied indirectly by inducing the current onto a conductor, such as a grounding wire, that attaches to the coaxial cable. The test signal on the center conductor may be received back at the headend, or it may be received near the injection point by breaking the coaxial cable, or by connecting a probe to the center conductor. The invention may employ ranging to determine the distance to the shield break.

Abstract: A table for forming trusses that includes channels that do not unduly deform or bend during truss construction comprises: a support frame; first and second substantially horizontally-disposed elongate panels; a first channel having a generally horizontal floor and opposed side walls extending upwardly therefrom; and a locator stop. Each of the panels has an upper surface, a lower surface, and opposing lateral edge portions, and the panels are positioned so that their respective upper surfaces are substantially coplanar and so that a first of the lateral edge portions of the first panel is in adjacent, non-contacting relationship with a first of the lateral edge portions of the second panel, thereby forming a gap therebetween. One of the side walls of the channel supports the lower surface of the first panel, and the other of the side walls supports the lower surface of the second panel.

Abstract: A system for determining a composite signal level at which a signal path begins to generate non-linear distortion. A uses a reference test signal, which is preferably a short-duration burst of repeatable broadband energy, that is passed through the signal path and received on a digital signal acquisition unit. An impaired received reference test signal is comprised of is formed from the transmitted reference test signal, linear distortion components, and non-linear distortion components. The impaired received reference test signal is digitally processed to reveal the non-linear distortion components. The impaired received reference test signal may be processed with a stored reference test signal to find a time-domain impulse response from which the uncorrelated distortion energy can be measured.