Abstract: The present invention provides an improved apparatus and method for detecting a reverse carrier signal. The present invention utilizes a peak detector/envelope filter for determining the peak level of the reverse analog waveform. The peak level is compared to a threshold level during a predetermined time period to determine the presence of a valid reverse carrier signal. Once determined, an enable signal is provided to an electronics device that allows further transmission of the reverse signals.

Abstract: The present invention provides an apparatus and method for reducing the amount of ingress noise that is present in the reverse path of a two-way communication network. The present invention employs intelligent dynamic switches (200) that determine whether desirable reverse signals are present at that point in the network. If so, the reverse signals, which also probably include some amount of ingress noise, are allowed to pass further upstream. If no desirable reverse signals are present at that point in the network, the IDS (200) blocks the transmission of any reverse signal further upstream, thereby blocking the transmission of any ingress signals. Although ingress noise is allowed to travel upstream with desirable reverse signals, the performance of the overall network is improved because ingress signals are blocked at various points in the network, thereby reducing the total amount of cumulative ingress noise signals that would otherwise be present in the network.

Abstract: An optical commutator (310) for combining optical signals emanating from a plurality of optical transmitters (305a-n). The commutator (310) includes a plurality of input ports connected to each optical transmitter (305a-n) via an optical fiber (315a-n). The optical transmitters transmits the optical signals within a predetermined bandwidth. A switching means (410) sequentially connects each of the plurality of input ports to an output port (415), where each of the plurality of inputs ports is connected to the output port (415) at a frequency greater than twice the predetermined bandwidth. The output port (415) then provides a combined optical signal that includes the plurality of optical signals.

Abstract: An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Furthermore, the architecture allows a central concentrator to support a plurality of remote devices that each have guaranteed bandwidth through connection-oriented allocations of bi-directional data flows. The upstream and downstream bandwidth allocation can support symmetrical bandwidth as well as asymmetrical bandwidth in either direction. The architecture generally can be used to support connection-oriented physical layer connectivity between a remote device and the central concentrator.

Abstract: An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Also, the modulation indices of various upstream frequency channels may be different, but a plurality of upstream channels may be used to carry a single data flow generally in parallel. The upstream data flow is fragmented into blocks and formed into superframes to allow transmission over at least one upstream frequency channel. When a plurality of upstream frequency channels are utilized, the superframes facilitate the possibility of having different modulation indices on the plurality of frequency channels.

Abstract: An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Furthermore, the architecture allows a central concentrator to support a plurality of remote devices that each have guaranteed bandwidth through connection-oriented allocations of bi-directional data flows. The upstream and downstream bandwidth allocation can support symmetrical bandwidth as well as asymmetrical bandwidth in either direction. The architecture generally can be used to support connection-oriented physical layer connectivity between a remote device and the central concentrator.

Abstract: A burst-mode optical transmitter (405) for receiving reverse electrical signals and for providing a reverse optical signal in a communications network. The optical transmitter includes a carrier-detect circuit (510) for detecting the presence of reverse electrical signals and a laser (535) for converting the reverse electrical signals into reverse optical signals for further transmission. The carrier-detect circuit (510) controls a switch (515), whereby when the carrier-detect circuit (510) detects the presence of reverse electrical signals, the carrier-detect circuit (510) closes the switch (515) activating the laser (535). When a reverse electrical signal is present, the carrier-detect circuit (510) opens the switch (515), deactivating the laser (535). In this manner, the burst-mode optical transmitter (405) only transmits reverse optical signals when reverse electrical signals are present.

Abstract: The present invention is directed towards an open-loop thermal compensation circuit that is suitable for use in a burst-mode laser transmitter. The compensation circuit adjusts the optical power level to ensure that the laser diode remains at an optimum power level. The thermal compensation circuit includes a thermistor having a thermal current, which is dependent upon any temperature fluctuations, where the thermal current adjusts a laser current. A change in the laser current subsequently adjusts the optical power level. Also included is a control circuit for turning on and off the laser diode with a control current, which is dependent upon the presence or absence of incoming electrical signals.

Abstract: An optical commutator (310) for combining optical signals emanating from a plurality of optical transmitters (305a-n). The commutator (310) includes a plurality of input ports connected to each optical transmitter (305a-n) via an optical fiber (315a-n). The optical transmitters transmits the optical signals within a predetermined bandwidth. A switching means (410) sequentially connects each of the plurality of input ports to an output port (415), where each of the plurality of inputs ports is connected to the output port (415) at a frequency greater than twice the predetermined bandwidth. The output port (415) then provides a combined optical signal that includes the plurality of optical signals.

Abstract: A transmitter (305) for transmitting reverse optical signals in a broadband communications system (300) that includes a converter (320) for digitizing the analog RF signals and a carrier-detect circuit (330) coupled to the converter (320) for detecting when digital RF signals are present at the output of the converter (320). When the carrier-detect circuit (330) detects digital RF signals, the carrier-detect circuit (330) allows the digital RF signals to be transmitted upstream through the broadband communications system (300). A digital network (310) then combines the received digital RF signals with other digital RF signals from additional transmitters (305). The combined digital signals are then provided to a receiver (315) that includes a converter (335) for returning the digital RF signals to analog RF signals and then providing the analog signals to a headend for further processing.

Abstract: The present invention describes a method for transmitting reverse analog signals within a specific portion of a reverse band in an HFC communications system. Subscriber equipment (305) receives input defining the specific portion of the band for transmitting reverse analog signals. An optical transmitter (315) then converts the received reverse signals to digital reverse signals and transmits the digital reverse signals at a specified clock rate. Due to shifting of the digital reverse signals within the reverse bandwidth, shifting of the received digital signals reflect the specific bandwidth within which the reverse signals were originally transmitted.

Abstract: A burst-mode optical transmitter (405) for receiving reverse electrical signals and for providing a reverse optical signal in a communications network. The optical transmitter includes a carrier-detect circuit (510) for detecting the presence of reverse electrical signals and a laser (535) for converting the reverse electrical signals into reverse optical signals for further transmission. The carrier-detect circuit (510) controls a switch (515), whereby when the carrier-detect circuit (510) detects the presence of reverse electrical signals, the carrier-detect circuit (510) closes the switch (515) activating the laser (535). When a reverse electrical signal is present, the carrier-detect circuit (510) opens the switch (515), deactivating the laser (535). In this manner, the burst-mode optical transmitter (405) only transmits reverse optical signals when reverse electrical signals are present.

Abstract: The present invention describes a method for transmitting reverse analog signals within a specific portion of a reverse band in an HFC communications system. Subscriber equipment (305) receives input defining the specific portion of the band for transmitting reverse analog signals. An optical transmitter (315) then converts the received reverse signals to digital reverse signals and transmits the digital reverse signals at a specified clock rate. Due to shifting of the digital reverse signals within the reverse bandwidth, shifting of the received digital signals reflect the specific bandwidth within which the reverse signals were originally transmitted.

Abstract: A hybrid fiber coax communications system includes plural coaxial distribution plants, fiber optic nodes, fiber optic links and a headend. At least one subscriber is coupled to each coaxial distribution plant. In the upstream signal path, the upstream signals travel from the coaxial distribution plants to the fiber optic nodes and through the fiber optic links to the headend. In the headend, optical receivers receive each upstream signal and pass the signals to respective node switches. The node switches selectively connect the upstream signals to a demodulator. An element control manager provides a control signal to the node switches to control whether the switch is in an open or closed state. One of the switches can be selected to be closed so that the demodulator receives one of the upstream signals.

Abstract: Off-premises cable television pay per view apparatus is coupled between first and second diplexers of off-premises subscriber service providing equipment. The diplexers separate the transmission path between a headend and a subscriber into downstream or forward and upstream or reverse transmission paths. A radio frequency transmitter is coupled between a controller and the upstream diplexer which may actuate a selected one of a plurality of data channels in the notoriously noisy subsplit 5-30 megahertz transmission spectrum for reporting billable events. On-premises equipment is minimized to comprise only a unidirectional data transmitter. The data transmission is sent repetitively over a predetermined period of time before the data transmitter, comprising a microprocessor, turns itself off to conserve power.

Abstract: A cable television interdiction apparatus comprises a microprocessor actuation and control means for actuating and controlling one or more frequency agile voltage controlled oscillators. The voltage controlled oscillators selectively jam only unauthorized premium programming transmitted from a headend to a particular subscriber. The method of interdiction comprises the steps of generating and storing voltage control words for operating the oscillators consistent with a headend selected jamming factor for a particular channel to be jammed and addressably transmitted and stored premium programming authorization data.

Abstract: An off-premises method and apparatus for the interdiction of unauthorized channels of a broadband cable television signal includes common circuitry for adjusting the amplitude and equalization levels of the broadband CATV signals and one or more subscriber modules for generating jamming signals of different frequencies which are used to interdict one or more unauthorized channels. Each subscriber module is associated with a subscriber and is programmable and addressable to adjust the jamming parameters of that subscriber independently of other subscribers. Each subscriber module circuit comprises a plurality of latches, each of which is associated with one of a plurality of digital to analog converters. Each of the digital to analog converters drives one or more frequency agile oscillators with its analog output to generate the jamming signals.

Abstract: A polarity reversing DC power inserter circuit for remotely located equipment such as interdiction apparatus or other signal control apparatus used in a cable or community antenna television (CATV) signal distribution system. A power transformer circuit receives a 117 volts AC power source at a subscriber's premise and converts it to a lower voltage positive and negative DC. A polarity reversing circuit comprising switching transistors and a 50% duty cycle multivibrator switches between the lower voltage DC at a frequency less than 10 Hz so as to avoid shock hazards associated with normal alternating current, while alternating sufficiently often to avoid electrolysis and corrosion problems associated with use of direct current (DC) powering. The reversing polarity DC power is then inserted into a cable drop to be provided uplink to the signal control apparatus.

Abstract: A off-premises CATV system includes a compensation control including a picture carrier controlled automatic gain control and an automatic slope control. A broadband television signal output from a variable gain device is distributed by a radio frequency signal splitter to a number of subscribers interdiction. The variable gain device and a variable frequency dependent device are connected in series for automatic gain control and automatic slope control, respectively. A first feedback control is used to compare a first portion of the broadband television signal to a reference power level and null the error. A second feedback control is used to compare a second portion of the broadband signal to the first portion and null the error. A second embodiment of the second feedback control differences the first and second portions of the broadband television signal. The first predetermined portion is a band of frequencies (high band) between 250 MHz. and 310 MHz.

Abstract: A pulse generator for generating pulses for modulation onto a carrier or subcarrier of a composite television signal is provided. The pulse generator includes a memory such as an EPROM for storing one or more waveshapes. Each stored waveshape is defined by a sequence of addressable values representing the amplitude of the waveshape as a function of time. A selecting circuit such as a microprocessor selects one of the waveshapes in the memory. A counting circuit responsive to a clock signal controls the address lines of the memory to read the amplitude values corresponding to the selected waveshape from the memory. The amplitude values are supplied to a digital to analog converter to convert the amplitude values to an analog pulse. The pulse may then be filtered to remove clock noise. The resultant signal is supplied to an amplitude modulator for modulating the signal onto a carrier or subcarrier of a composite television signal.