Abstract: Various methods of detecting leakage of a signal from a Data-Over-Cable Service Interface Specification (DOCSIS) 3.1 channel are disclosed, including using a DOCSIS 3.1-defined “exclusion band” to insert existing tagger-based test carriers, using a power signature algorithm to detect the presence of DOCSIS 3.1-defined pilot carriers, and using a time-based correlation technique to detect the presence of DOCSIS 3.1-defined cyclic prefixes.

Abstract: In a communication network, a node at a subscriber premises includes an input/output (I/O) port, and a device for monitoring a subscriber premises. The device includes an upstream signal path including a first switch, a downstream signal path, and a controller having an input/output (I/O) port coupled to the I/O port of the node, and a first output port. The first switch is coupled to the first output port selectively to complete the upstream signal path.

Abstract: In a method for detecting leakage in a digital cable system, at least one first signal is inserted on the cable system. The at least one first signal has an amplitude multiple tens of dB below the digital channel power of the digital channels carried on the cable system. A second signal containing the first signal is received. The second signal is converted to an intermediate frequency (IF) signal. The IF signal is digitized and samples of the digitized IF signal are obtained. Digitized samples of a third signal at the nominal frequency of the first signal at maximum amplitude converted to the IF are provided. The digitized IF signal and the digitized samples of a third signal at the nominal frequency of the first signal at maximum amplitude converted to the IF are correlated. The presence of the inserted first signal is detected based upon the result of the correlation. In another method, a pair of first signals are inserted on the cable system.

Abstract: A method and apparatus for detecting leakage of a digital CATV channel signal from a CATV system. The digital CATV channel signal is amplitude modulated with a tag signal having a frequency in the range of about 3 Hz to about 35 Hz, and coupled to the CATV system. At a point of leakage from the CATV system, the amplitude modulated digital CATV channel signal can be detected using a leakage detector capable of recovering the tag signal.

Abstract: “Cradle-to-grave” treatment of leaks begins with technicians logging leakage signal strengths and GPS latitude and longitude coordinates in technicians' vehicles as the technicians go about their daily assignments. Leakage signal strengths and GPS latitude and longitude coordinates are then uploaded to a leakage server. The server calculates leak latitude and longitude coordinates and signal strengths. The system sends the leakage signal strengths and/or calculated leak latitude and longitude coordinates to technicians' vehicles, for example, as components of, or attachments to, work orders. The latitudes and longitudes are converted by GPS navigators in the technicians' vehicles to turn-by-turn directions to the calculated leak locations. The technicians drive to the leaks, identify and repair them, and close the work orders.

Abstract: A method of identifying a source of ingress into a network includes storing frequency spectra of known sources of ingress, comparing the frequency spectrum of ingress to the frequency spectra of known sources of ingress, and determining from the comparison which of the frequency spectra of known sources of ingress is closest to the frequency spectrum of the ingress. Apparatus for identifying a source of ingress into a network includes memory for storing frequency spectra of known sources of ingress and a device for comparing the frequency spectrum of the ingress to frequency spectra of known sources of ingress and determining from the comparison which frequency spectrum of a known source of ingress is closest to the frequency spectrum of the ingress.

Abstract: An underwater diving mask for use by a diver in an underwater diving environment has a viewing portion defined by the diver's face and a lens, a visual display device proximate the viewing portion to provide visual images to the diver, a speaking chamber configured to sealing engage a portion of the diver's mouth to permit the diver to speak, and a sound transducer located proximal the speaking chamber. A computer system is disposed in a portion of the mask and is operatively coupled to the sound transducer and to the visual display device, where the computer system, the viewing portion and the speaking chamber are sealing isolated from the underwater diving environment.

Abstract: An apparatus for testing the phase linearity of a network comprises a first local oscillator, a first mixer, and a first filter, a second local oscillator, and a second mixer for mixing the first IF to the desired output frequency. The output of the second mixer is coupled to a second filter which passes the desired frequency band, but rejects the high frequency mixing harmonics produced in the second mixer. The output of the second filter is coupled to a variable gain amplifier capable of amplifying the frequency band of interest to the desired level and a third filter which further rejects unwanted high frequencies in the output.

Abstract: Underwater position determination is provided by combining sonar-derived ranging data between a sonar receiver and a sonar transmitter with GPS position data to provide geographically-referenced position data accurately representing the position of a sonar receiver carried or worn by a diver or submersible vehicle. Function and accuracy enhancements are provided to compensate for diver and sonar transmitter and depth difference and differences of sonar signal propagation speed as well as several techniques of compensation for change of position of the GPS receiver and for logging diver and/or vehicle path.

Abstract: An attenuator includes a substrate having first and second surfaces and a plurality of discrete circuit elements. The first surface includes a first electrically conductive pattern providing circuit contacts providing electrical connections among the discrete circuit elements and circuit contacts providing electrical connections to components external to the attenuator. The second surface includes a second electrically conductive pattern.

Abstract: An attenuator includes a housing defining an interior, a front, a rear, and a rotor mounted between front and rear for rotation within housing about an axis of the rotor. First electrical contacts are provided on the housing. Second electrical contacts are provided on the rotor. The rotor includes multiple printed conductor boards. Each PC board includes an electrically relatively non-conductive substrate. One side of each substrate provides conductive areas through which electrically attenuating elements of the attenuator are coupled together to form an attenuating network providing a selected level of attenuation. Electrical contact is made between the first electrical contacts and the electrically attenuating elements of the attenuator through the second electrical contacts.

Abstract: A communication circuit carries at least one signal including synchronizing intervals by which output of the signal by first apparatus coupled to the communication circuit is to be synchronized. A communication method includes selecting and modulating at least a portion of the duration of at least some of the synchronizing intervals. A modulator is provided for selecting and modulating at least a portion of the duration of at least some of the synchronizing intervals. Another communication circuit carries at least a first signal including frequencies in at least a first frequency band. A method of determining whether the first signal is escaping from the circuit includes transporting along the circuit apparatus adapted for receiving the first signal, detecting whether a received signal includes frequencies in the first frequency band, and producing an indication that the received signal includes frequencies in the first frequency band.

Abstract: A method and apparatus for determining the location of an impedance mismatch in a digital communication circuit (22) generate (20) at least quasi-random data, transmit the data along the circuit (22) from a transmitting end of the circuit (22), recover (24) reflections from impedance mismatches in the circuit (22) adjacent the transmitting end of the circuit (22), correlate the reflections with the data to generate a correlation result, identify a reflection peak in the result, and multiply the propagation velocity of the data through the circuit (22) by a time delay to the reflection peak.

Abstract: A 1-by-N switch matrix (10) includes at least two ranks of switches (12-1, 12-2-1, 12-2-2, 12-3-1, . . . , 12-3-4, 12-4-1, . . . , 12-4-8, and 12-5-1, . . . , 12-5-16; 112-1, 112-2-1, 112-2-2, 112-3-1, . . . , 112-3-4, 112-4-1, . . . , 112-4-8, and 112-5-1, . . . , 112-5-8). Each switch has first, second and third terminals (1, 2, 3). A first state of each switch couples the first terminal (1) to the second terminal (2) and a second state of each switch couples the first terminal (1) to the third terminal (3). The second (2) and third (3) terminals of each switch (12-1, 12-2-1, 12-2-2, 12-3-1, . . . 1., 2-3-4; 112-1, 112-2-1, 112-3-3 and 112-3-4) of each rank (-1-, -2-, -3-) above the next to lowest rank (-4- or -3-) are coupled to first terminals (1) of respective switches (12-4-1, . . . , 12-4-8 and 112-3-1, 112-3-2, 112-4-5, 112-4-8) in the next lower rank (-2-, -3-, -4-). The second (2) and third (3) terminals of each switch (12-4-1, 12-4-8 and 112-3-1, 112-3-2, 112-4-5,. . .

Abstract: A method and apparatus for locating the source of noise ingress into a CATV system return path by coupling a filter having a passband in the noise frequency bandwidth to the nodes between adjacent return path amplifiers. The filter is sequentially coupled to the nodes, working away from the CATV system headend. A signal level meter or the like monitors the effect on the noise of coupling the filter to the nodes. When a node is reached at which coupling of the filter to the node no longer has any effect on the signal level in the node, the source of the noise is isolated in the node immediately preceding the node under test.

Abstract: A system (10) for monitoring the ingress of noise into the return path (14) of a two-way CATV network comprises a detector circuit (16, 116) coupled to the return path (14) to receive a signal from the return path (14). The detector circuit (16, 116) provides an output signal indicative of the signal coupled from the network. A peak follower circuit (20, 120) coupled to the detector circuit (16, 116) stores a peak detected output signal from the detector circuit (16, 116). Illustratively, the peak follower circuit (20, 120) is coupled to the detector circuit (16, 116) through a filter circuit having a passband, for example, a low pass filter (18, 118). The peak follower circuit (20, 120) stores a peak detected output signal within the passband. A mixer (128) may be included for mixing the signal from the network with a local oscillator (126) frequency to produce a mixed signal, and for supplying the mixed signal to the detector circuit (16, 116).

Abstract: A communication system includes a transmission channel, a relay having first and second states, an operating power port, a first signal input port, a second signal input port and a signal output port. A power supply supplies power to the relay to place the relay alternately in the first and second states. The system further comprises first and second sources of program material to be selectively and alternately transmitted in the channel. The first and second sources of program material are characterized by at least one program material frequency. The first signal input port of the relay is coupled to the first source of program material. The signal output port of the relay is coupled to the transmission channel. A first inductance is provided for coupling the power supply to the operating power port. The relay includes a second inductance coupled across the power port for controlling the relay's state.

Abstract: A communication circuit comprises sources of program material, carrier frequency signal sources and first modulators for modulating the carrier frequency signal sources with the program material sources. Each of the first modulators has a first input terminal, a second input terminal and a first output terminal. Terminal apparatus for demodulating program material-modulated carrier frequency signals include automatic gain control (AGC) circuits having AGC bandwidths. One of the program material sources is coupled to the first input terminal of a respective first modulator through a second modulator having a third input terminal, a fourth input terminal and a second output terminal. A source of signals having a frequency in the AGC bandwidth is coupled to the third input terminal. The source of program material is coupled to the fourth input terminal. The second output terminal to the first input terminal.

Abstract: An information system comprises an information network and a station apparatus capable of receiving information from the network and sending a command to the network. An isolator comprises a first diplex filter having an input/output (I/O) port coupled to the network for passing signals with frequencies in first and second non-overlapping ranges. An output port is provided for signals with frequencies in the first range, and an input port is provided for signals with frequencies in the second range. A second diplex filter has an I/O port coupled to the station apparatus for passing signals with frequencies in both the first and second ranges. An input port is provided for signals with frequencies in the first range, and an output port is provided for signals with frequencies in the second range. A first circuit having a bandwidth including the first range provides a first signal path between the output port of the first diplex filter and the input port of the second diplex filter.

Abstract: An attenuator includes a housing defining an interior, a front, a rear, and a rotor mounted between front and rear for rotation within housing about an axis of the rotor. First electrical contacts are provided on the housing. Second electrical contacts are provided on the rotor. The rotor includes multiple printed conductor boards. Each PC board includes an electrically relatively non-conductive substrate. One side of each substrate provides conductive areas through which electrically attenuating elements of the attenuator are coupled together to form an attenuating network providing a selected level of attenuation. Electrical contact is made between the first electrical contacts and the electrically attenuating elements of the attenuator through the second electrical contacts.