Abstract: Electric domain reversals are arranged in parallel arrays on a piezoelectric ceramic substrate to form strong reflectors of surface acoustic waves in devices such as filters, resonators and the like. The domains are prepared by a poling process involving the use of a selective electrode pattern to which a high DC voltage is applied at a temperature above ambient but below the Curie temperature of the substrate.

Abstract: An AGC system is described for setting a plurality of different AGC delay points for various channels or bands of channels in a television receiver. In one embodiment, the system includes an AGC control which develops a gain control signal for the UHF and VHF tuners, and an AGC delay circuit which determines the point at which the gain control signal becomes effective to initiate gain reduction in the tuners. Preferably, the delay circuit causes the AGC control to establish a first AGC delay point, corresponding to a given level of incoming signal strength, at which the gain control signal causes the VHF tuner to begin gain reduction, and establishes a different delay point corresponding to a relatively higher level of incoming signal strength at which the gain control signal causes the UHF tuner to begin gain reduction. In another embodiment, a separate AGC delay point is set for channel 6 to provide a more desirable delay point for other channels in the VHF band.

Abstract: A display system is disclosed for receiving video data from a character generator and for applying that data to a beam index tube. The system includes a memory for storing data received from the character generator and for outputting the stored data in response to an index clock signal which is derived from a conventional index signal generated by the tube. Output circuitry receives the data from the memory and outputs that data to the tube at the proper times for illuminating phosphors within the tube. The preferred embodiment also drives the tube's beam current in a manner which develops a video image having improved contrast.

Abstract: A decoder is responsive to a decode authorization signal for unscrambling a broadcast RF television signal having randomly suppressed horizontal blanking and synchronization pulses. The decoder comprises a tuner having a gated automatic gain control circuit and a video detector responsive thereto for developing a baseband video signal corresponding to the broadcast television signal. The decoder further comprises a sync restoration circuit developing a standard horizontal synchronization pulse in response to each suppressed horizontal blanking pulse of the baseband video signal, the standard horizontal synchronization pulses being continuously combined with the baseband video signal for operating the automatic gain control circuit and being coupled for unscrambling the baseband video signal only in response to the decode authorization signal.

Abstract: A balanced, constant current power supply having two rectifying bridges coupled in parallel is energized by an AC source for generating a plurality of DC output voltages. The parallel arrangement of diode rectifying bridges permits the use of low cost, polar electrolytic capacitors in the power supply and results in a balanced circuit capable of generating a plurality of parallel DC outputs. The AC-driven, DC power supply of the present invention operates without a transformer and, in combination with a plurality of shunt regulators, is capable of providing a plurality of well-regulated DC output voltages.

Abstract: A protection circuit for a switching regulator power supply comprises a series-pass transistor having a collector-emitter circuit connected between a source of DC operating potential and the power supply. A bootstrap signal developed by the power supply and having a voltage level greater than the potential of the DC source is fed back to the base of the series-pass transistor for rendering the transistor fully conductive under normal operating conditions and to improve performance under marginally low levels of the DC source. A reverse biased diode is connected between the base of the series-pass transistor and the DC source to limit the transistor's base drive via the feedback path to a safe level. A shunting transistor is responsive to an overvoltage condition of the DC source for reducing the base drive of the series-pass transistor to limit the DC potential supplied to the power supply to a safe level.

Abstract: A television signal audio transmission system comprises transmission means for developing first and second stereophonically related audio signals and means for developing a third audio signal. The transmission means further includes circuitry for developing a composite baseband signal having a first component comprising the sum of the first and second audio signals, a second component comprising a double sideband suppressed carrier signal formed by amplitude modulating a 2f.sub.H subcarrier with the difference between the first and second audio signals, a third component comprising a pilot signal having a frequency f.sub.H and a fourth component comprising a 4f.sub.H subcarrier signal frequency modulated according to the third audio signal, where f.sub.H represents the horizontal scanning line frequency. The composite baseband signal may include a fifth component comprising an approximately 5.5f.sub.

Abstract: Cooling means are disclosed for cooling the face panel of a projection cathode ray tube. The cooling means comprises a housing having a rearwardly extending flange with a forwardly tapering section configured to nest with the forwardly tapering section of the face panel when mated therewith. The housing has a window section for framing and passing the image formed on a cathodoluminescent screen on the inner surface of the face panel. Spacing means are provided for spacing the window section of the housing from the face panel window section, and bonding means provide for bonding and hermetically sealing the tapering sections together. A cooling medium is located in the space between the windows for cooling the face panel.

Abstract: To hold three CRTs in proper optical alignment in a projection television system, each of three pods holds one CRT. Each pod includes a cylindrical housing for holding the front piece of a CRT, and a back cover which holds the CRT inside the housing. Preferably, each housing is adapted to hold its CRT at a preselected rotational position and at a preselected tilt angle with respect to a straight ahead optical projection axis.

Abstract: A novel optical assembly is disclosed for use in an ultra-compact, jack-in-the-box projection television receiver. The stationary optical assembly is permanently installed in a lower portion of the cabinet for forming a television image, and projecting an aerial image of the television image upwardly a predetermined image projection distance along an optical path folded by optical path folding means. The receiver includes a unitary optical assembly having a viewing screen selectively storable in the cabinet and elevatable therefrom for receiving and displaying the image. The stationary optical assembly comprises the following, in combination: an image source means for forming the television image, a cathode ray tube holding assembly, and mirror means to reflect the aerial image steeply upward along the folded optical path. Also included are chassis means for receiving and supporting the image source means, CRT holding assembly, and mirror means.

Abstract: Apparatus for simultaneously controlling the operating modes of a plurality of coupled video signal processing devices is disclosed. Manually operated pushbutton selectors provide D.C. control voltages to a plurality of electronic RF switches to permit the simultaneous viewing and recording of signals from various sources such as cable TV (CATV), subscription TV decoder (STV), video record (or disc) player, etc., in any desired combination. Video signal losses due to signal splitting are avoided when viewing and recording the same input signal by means of unique cooperation between view and record manually operable selectors. Electronic diode switching circuitry controlled by a minimum number of user selectable inputs allows for a reduced number of controller components and simplified design while facilitating user operation.

Abstract: A lid-raising device is disclosed for use in an ultra-compact, jack-in-the-box television receiver housed in an open-topped cabinet. The cabinet has a lid pivotally attached at the back thereof for selectively opening and closing the cabinet for emergence and storage of a unitary optical assembly elevatable from and nestable within the cabinet by a precision elevating device, and includes a rear-projection screen for displaying a television image upon its emergence. The unitary optical assembly includes a rigid, box-like shroud having a slanted back and an open front for receiving and supporting the screen.

Abstract: A method and structure is disclosed for isolating the shield of a shielded conductor system from a low frequency power source to which the shield may be connected. In one embodiment, the isolation technique includes providing an interruption in the conductor's shield and situating within the interruption dielectric and magnetically absorptive material so as to create at least a pair of capacitance across the interruption, and such that the capacitances are separated by magnetically absorptive material. In this manner, low frequency isolation is achieved and the field within the cable is shielded from ambient high frequency electromagnetic interference which could otherwise leak through the interruption into a desired high frequency signal path within the conductor. In other embodiments, at least some of the dielectric material forms part of a series resonator to improve attenuation of electromagnetic interference at low VHF frequencies.

Abstract: A method and apparatus is described for dividing a clock frequency by any odd number to obtain a symmetrical output. Generally, some dividers in a chain of divide-by-two dividers are designated as controlled dividers and others are designated as uncontrolled dividers. The clock input of each controlled divider receives the output of an exclusive NOR gate, the inputs to which include the output of the last divider in the chain and either the clock signal or the output of a preceding divider, depending on certain criteria. The clock input of each uncontrolled divider receives the output of an immediately preceding divider. With this arrangement, the last divider in the chain develops a divided output which is symmetrical.

Abstract: A power supply for use in a computer terminal capable of providing a plurality of direct voltage signals to the computer terminal logic system while isolating this logic circuitry from the line voltage is disclosed. A high frequency power supply transformer and associated circuitry provides the various direct voltage signals to the computer terminal logic system and provides isolation between the line input and logic circuitry. Parallel isolation is provided by a horizontal sync coupling circuit which is driven by the logic system and which, in turn, synchronizes the horizontal deflection system. The direct voltage signals provided to the logic supply system are both scan- and pulse-derived from the horizontal sweep signal permitting various computer terminal systems to be operated by display-derived power output signals.

Abstract: A pair of elongate rail members are secured along opposed edges of a printed circuit board for protecting the solder fillets formed on the foil side of the board and to facilitate convenient screwless mounting of the printed circuit board to a substantially flat platform of a television receiver chassis or the like. Each rail member comprises a printed circuit board supporting surface and a substantially flat base adapted for mounting on the platform, the base being spaced from the supporting surface by a distance greater than the length of the solder fillets. The rail members are secured to the printed circuit board by resilient tabs which snap lock the foil surface of the board in abutment with the supporting surface. At least one locking member depends from the base of each rail and is received for limited longitudinal movement within an elongate slot formed in the platform, the locking members and base forming a bite for capturing an edge of the platform at one limit of longitudinal movement.

Abstract: Means are disclosed for use in a line printer having a print head for traversing between a first side frame and a second side frame. The print head is driven in its traverse by a flexible belt close-looped between an idler pulley and a driven pulley. A predetermined tension of the belt is provided and maintained by the means and method according to the invention.

Abstract: A television signal processing apparatus is responsive to a received television signal for translating the frequency spectrum thereof to a frequency band characterized by a fixed frequency carrier signal frequency modulated in accordance with a baseband audio signal. The frequency modulated carrier signal is combined with an unmodulated CW muting signal having a frequency approximately equal to the frequency of the carrier signal to facilitate remotely controlled muting of the baseband audio signal in accordance with the FM capture effect.

Abstract: A projection optical system is disclosed that is protractible and retractible within a narrow spatial column for emerging from and nesting in a cabinet of an ultra-compact, rear-projection television receiver. The system comprises in combination a stationary optical assembly permanently enclosed in a lower portion of the cabinet and having image projection means and first mirror means. A protractible optical assembly is elevatable as a unit from the cabinet; the assembly includes a mirror and a rear projection screen. The mirror and screen are at angles effective to reflect and receive, respectively, an aerial image of the television image formed by the image projection means of the stationary optical assembly. The angles are also effective for nesting the mirror and the screen with components of the stationary optical assembly. The optical system, when retracted and nested is overall depth-wise-shallow and the receiver is as compact as a conventional, large-screen console television receiver.