Abstract: The automatic gain control circuit of the present invention improves upon conventional techniques using a pilot carrier for control by monitoring for the presence of the pilot carrier. If the pilot carrier level is at an undetectable level, it will switch control of the level control section of the automatic gain control circuit to the equivalent thermal setting by means of a switch. The switch connects the output of a temperature-sensing network to a Bode driving circuit that approximates attenuation of a given transmission medium over temperature. The gain setting will therefore be based on an approximation of what the cable losses should be at the detected temperature of the amplifier housing. The present invention provides dynamic gain adjustment, even in the event of pilot carrier signal loss.

Abstract: A broadband communications system for coupling telephony or other digital networks to a CATV network. The system transmits a multiplex of telephony signals in the forward band of the CATV network. The forward telephony channels are demodulated and demultiplexed by a plurality of subscriber terminals into the individual telephony signals directed to an addressed subscriber. Signals returning from subscribers are digitized into standard telephony signals onto the reverse band of the CATV network, and demodulated and multiplexed into a standard telephony signal that is interfaced to the telephony network. A multiplicity of subscribers are initially assigned to a selected reverse band channel. If more than one subscriber contends for use of the reverse channel by transmitting in the channel, signals from the contending subscribers interfere and prevent any subscriber's identity from being decoded and acknowledged. The contending subscribers wait for a random wait time and re-attempt to transmit.

Abstract: A communication system for coupling telephony or other digital networks to a broadband network such as a CATV network. The system transmits a multiplex of telephony signals in the forward band of the broadband network, with individual signals directed to an addressed subscriber. Telephony signals returning from subscribers are modulated onto the reverse band of the broadband network in a frequency division multiplex (FDM). The modulated telephony signals are received at a telephony network interface coupled to the broadband network. A selected plurality of modulated telephony signals are frequency shifted to baseband. The baseband-shifted telephony signals are sampled to generate a plurality of time division multiple access telephony signal samples. A plurality of time division multiple access telephony signal samples are channelized into a serial data stream with a channelizer.

Abstract: A headend method and apparatus for a digital transmission system is provided which includes inputs for receiving first and second program information from first and second program sources and inputs for receiving first and second control information from first and second control sources. The first and second program information is applied to a switching circuit and a switch control controls the switching circuit to output channels of program information comprising combinations of the first and second program information for output to a subscriber. Processing circuitry allows for selectively providing the first and second control information to the channels output from the switching circuit.

Abstract: An RF Choke and tap having improved insertion loss, amplitude modulated distortion of video and audio carrier signals at CATV frequencies. The RF choke includes a 20 AWG magnetic wire wound on a ferrite rod. The magnetic field effects of the choke are optimized by selecting the choke winding pattern, rod core material and positioning of a resistor between selected windings. The wire is wound by placing two groups of the 4 tightly wound wires adjacent the ends of the rod. A group of 3 very loosely wound wires is separated from the wound wires and placed between the groups of 4 tightly wound wires. A resistor is electrically connected to a first wire in one of the groups of tightly wound wires and connected to a first wire in the group of the loosely wound wires.

Abstract: A predistortion circuit for an optical communications system includes a main path for an RF modulating signal and a predistortion path for a predistortion signal, which signals are combined to modulate a laser diode. The distortion path includes a distortion generator which generates a distortion signal which is substantially the same as the distortion generated by the modulation of the transmission system with the RF modulating signals. In one implementation, the distortion generator comprises a square law device which preferably is a field effect type device. The square law device operational characteristic closely mimics the major component of distortion in optical communications systems, composite second order (CSO) distortion. In a second implementation, two square law devices are coupled in an anti-phase arrangement to substantially cancel odd order distortion components from the distortion signal and to enhance even order distortion components, particularly CSO.

Abstract: An apparatus and method is described for transmitting, receiving and communicating program data signals which are combined with digital data signals. Preferably, the present invention compresses 30 digital audio signals, multiplexes them with title, track, artist, record label, year, etc., program information, and transmits the combined signals via satellite to a receiving station. The receiving station demultiplexes the signals and sends them via a cable distribution system to a subscriber's digital music tuner. This tuner further demultiplexes and decodes the signals so that the digital audio signals may be converted to analog and output for listening, while the corresponding data signals are communicated to the subscriber. In an alternative preferred embodiment, the program data signals are transmitted to a remote control receiver where they are displayed. The system described in the present invention may be used for transmitting video, software or games with program data to subscribers.

Abstract: A predistortion circuit for an optical communications system includes a main path and a predistortion path for an RF modulating signal which are independently level adjusted and impedance matched to a laser diode. The distortion path includes a distortion generator which generates a distortion signal which is substantially the same as the distortion generated by the modulation of the transmission system. The distortion path further includes an in phase adjustment leg for overall amplitude adjustment and amplitude adjustment as a function of frequency and a quadrature adjustment leg for phase adjustment as a function of frequency. Temperature compensation is provided to the adjustment networks to stabilize the gain elements of each for ambient temperature changes.

Abstract: A near video on demand time shifting feature for a subscriber terminal emulates the video cassette recorder functions of pause, fast forward, and rewind for a NVOD service subscription. The subscriber terminal stores global transactions concerning NVOD events in an event portion of memory. The subscriber terminal provides an on screen display feature for assisting in ordering the NVOD service and a user interface which provides the functions of pause, fast forward and rewind. When viewing a NVOD event, if the subscriber selects the pause function, the subscriber terminal causes a pause on screen display to be viewed for one time increment. After the elapse of the time increment, the subscriber terminal will tune the channel of the next showing which is one time increment earlier than that presently viewed. If the subscriber selects the rewind function, the subscriber terminal will tune the channel of the next showing which is one time increment earlier than that presently viewed.

Abstract: A program control system for controlling access to premium programming and/or premium channels comprises a program control apparatus which may incorporate one or more subscriber modules. The subscriber modules may use one or more different types of program control technologies to provide different subscribers with different levels of access as well as different levels of security. One subscriber module may comprise a program control apparatus for interdicting premium programming signals transmitted "in the clear". Other modules may comprise positive or negative traps or bandstop filters. The program control apparatus allows a cable television provider to apply new or different program control technologies on a subscriber by subscriber basis.

Abstract: A subscriber terminal includes a receiver for receiving a television signal including video, audio, and data information. A channel of the television signal may be selected for display on the television. A memory stores channel identification information such as channel identifiers. The channel identifiers include at least one display character. A processor establishes a relationship between channel identification information and channel numbers associated with channels of the television signal. An on-screen display control circuit controls the display of character information on the television and has the capability of overlaying the channel number and the channel identification information on the video portion of a selected channel displayed on the television for a predetermined period of time. Program identification information such as program titles may also be displayed.

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 digital audio communication system includes a digital modulation and demodulation scheme which efficiently uses the bandwidth and channel spacing of a cable television system. A 30 channel digital bit stream is demultiplexed into six groups of five channels. Each group of channels thereafter modulates a carrier by a quadrature partial response (QPR) process. The QPR signal, an amplitude modulated, double sideband, carrier suppressed (AM DSBSC) signal, is then transmitted over the cable system to a multiplicity of subscribers, each of which has a QPR demodulator. The demodulators are of the decision feedback type having a modified Costas loop carrier recovery circuit. The grouping of an odd number (five) of digital audio channels per QPR modulator minimizes error propagation due to the correlative QPR demodulation process. The decision feedback decoding is implemented in simple current nodes where a bilevel output from the decoded data is subtracted from a tertiary level output of a mixer.

Abstract: Off premises cable television interdiction apparatus comprises a microprocessor actuation and control means for actuating and controlling at least one frequency agile voltage controlled oscillator. The voltage controlled oscillator selectively jams only unauthorized premium programming transmitted in the clear from a headend to a particular subscriber. The voltage controlled oscillator generates a jamming signal carrier at a frequency 1/N between the video and audio carriers where N is an integer, preferably small. The microprocessor provides a calibration mode and a normal mode of operation. During the normal mode of operation, a frequency hopping rate on the order of four thousand hertz is achievable. the method of interdiction comprises the steps of generating and storing voltage control words for operating the oscillator consistent with a headend selected jamming factor for a particular channel to be jammed and addressably transmitted and stored premium programming authorization data.

Abstract: A remote control system including a hand held remote control unit with an alphanumeric information display, for controlling and communicating with a first controlled device, such as a digital music tuner connected to a community antenna television (CATV) cable, and for controlling a selected one of a plurality of second controlled devices, such as CATV set-top units, VCRs, or television sets. A first, high speed, error free display information communications protocol is utilized for transmitting program content or other information from a device, such as the CATV-connected music tuner, to the remote control unit for display. A second or control communications protocol is utilized by the remote control unit for controlling the first controlled device and a selected one of the second controlled devices. The CATV cable-connected music tuner utilizes the 44.

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.