Abstract: A tuning system for use in radio frequency multi-signal receiving systems, e.g a CATV converter, utilizes a closed feedback loop digital arrangement for channel selection (local oscillator frequency control) and channel fine tuning. The system may be implemented either via discrete hardware or through the use of microprocessor controlled apparatus.

Abstract: Switching apparatus for selectively applying either video game signals or conventional television program signals to a television receiver includes a pair of complementary filters to respectively pass and block the transmission of signals within a selected game-display channel. A switch may be selectively placed in either a game-playing mode or a program-receiving mode. In the latter mode the switch connects an input cable to the receiver. Correspondingly, when used for video games, the switch passes the incoming cable signal through one of the filters to a video game-playing adaptor and player which, in turn, are connected back to the receiver through the other of the filters.

Abstract: An improved system arrangement for distributing and permitting use of an ensemble of program controlled television games includes head end apparatus for impressing an array of game-regulating programs onto an electronic distribution system, e.g., by time division multiplexing into an assigned frequency band on a television program distributing CATV or MATV cable. At any of plural receiver locations connected to the distribution channel, a user desiring a game selects ("tunes") the game frequency band and loads a game program memory (RAM) with the program for the particular game desired. The composite apparatus then functions in the now per se conventional manner to actually implement the selected game in conjunction with a television receiver and player control(s).

Abstract: A programmable multi-digit register loads plural bits of fixed binary information, represented by a pattern of short or open circuit connections, onto a printed electronic circuit board or the like. A modular, plural-bit generally trapazoidal shaped metallic blank is formed having first and second facing legs connected by links in one-to-one correspondence with the bits-per-module. One leg is scored at each link, and each leg has tabs insertable in circuit board apertures.In use, each register module is bent and soldered in place in a circuit board via the tabs, and one end of each link isolated by cutting through the score lines. The individual binary digits are then programmed into the module by selectively severing the links.

Abstract: An improved overvoltage protection circuit for cascaded radio frequency signal distributing amplifiers interrupts a power transmission path in an open circuit mode responsive to an overrange input power potential, and is automatically reset to its quiescent operative condition when the overvoltage condition abates. AC energy is coupled by the instant arrangement at a reduced level while the fault condition persists, such that the driven load is continuously energized.In accordance with one aspect of the present invention, selective relatively essential ones of the distribution amplifiers, e.g. trunk amplifiers, can be maintained operative by a DC standby power supply during an AC line power hiatus. Correspondingly, other, less important amplifiers are automatically rendered inoperative during power faults to prevent excessive drain in the DC standby source.

Abstract: Homodyne automatic frequency control circuitry maintains the mean or center output frequency of a controlled oscillator, e.g., the output of a voltage controlled oscillator effecting frequency modulation, equal to the output frequency of a reference oscillator. The composite AFC circuitry employs ganged sampling switches and a common mode error obviating common frequency detector (e.g., a discriminator) to alternately store voltages representative of the reference and controlled oscillator frequencies in capacitors connected to the inputs of a difference amplifier. The difference amplifier acts through an integrator to supply any necessary correction potential to the control port of the controlled oscillator when the signals stored in the two capacitors differ, signalling that the mean output frequency of the controlled oscillator has departed from that of the reference oscillator.

Abstract: Encription apparatus for restricting distribution of private (e.g., premium) video programs propagated by a CATV cable network, radiation or the like employs picture carrier isolating, phase shifting and linear combining structure for rendering the transmitted video information unrecoverable by conventional television receivers. Authorized receiving stations are provided with inversely functioning electronics which reconstitute the prescribed video amplitude modulation format to permit signal reception. Similar audio program modification and correction structure permits encription and selective reception of the sound portion of the distributed programming.

Abstract: Portable, plugable electrical test equipment signals the presence or absence of radio frequency energy within a predetermined frequency spectrum, as on a CATV or MATV video distribution system. The equipment comprises a cascaded bandpass filter, radio frequency amplifier, coupling-detector network, and operational amplifier to selectively energize a light emitting diode when a sufficient level of energy in the requisite frequency range is sensed.In accordance with one aspect of the present invention, the coupling-detector network includes circuitry for quiescently biasing the inverting and noninverting inputs of the operational amplifier to a state such that the LED is not activated. The circuitry further includes as an integral part thereof detector structure for reversing the relative potential amplitudes impressed on the amplifier inputs when a sufficient quantum of the subject radio frequency energy is coupled to the composite test equipment, such that an appropriate output indication is generated.

Abstract: A bilateral communications system, as for CATV application, distributes commercially available and premium video programming on a subscriber demand--directly accountable basis. At least the premium video programming is impressed on the cable in a frequency band and/or format not recoverable by a standard television receiver, absent receipt at a particular subscriber location of a reception-authorizing message from the system head end.A central processor at the system head end sequentially polls cable subscribers under stored program control, permitting bilateral digital communications between the subscriber and the head end.