Abstract: An integratable amplifier is disclosed for developing a high level output signal with reduced power dissipation. The amplifier includes a first circuit (108, 110) which responds to an input signal for developing first and second signal currents whose amplitudes increase and decrease, respectively, in response to an input signal transition of a given direction. A second circuit (32a) receives the first signal current for establishing a third signal current which mirrors the first signal current. The second and third signal currents are received by a third circuit (70a) for conversion thereof to an amplified output signal. To stabilize the gain of the amplifier, a negative feedback path (50a) is coupled between the input signal and the output signal.

Abstract: A method and apparatus are described for testing a line screen CRT for misregistration between its electron beam and the beam's phosphor stripe targets. The test method includes sensing light output at a plurality of test areas on the CRT screen as the electron beam is stepped across its phosphor targets. The maximum and minimum light outputs of each test area, and the beam locations at which the maximum and minimum light outputs were obtained, are used to compute the degree of misregistration for each test area.

Abstract: An improved spark gap device and configuration for coupling the device in circuit with equipment such as television receivers are disclosed. The spark gap device includes three conductive pads, the first and second of which are separated by a first gap. The third pad is separated from the other pads by a second gap which intersects the first gap. By coupling the first and second pads across A.C. power lines in the equipment, and by coupling the third pad to earth ground, the energy associated with a high voltage transient on the power lines causes the air in one of the gaps to ionize. Hence, a spark jumps the gap to shunt the transient energy to ground. The intersection of the gaps causes ionization to spread to the second gap and thereby provide an additional path to ground for the energy associated with the transient, thereby protecting components within the equipment.

Abstract: A method is described for plating the inner and outer circumferences of a cylindrical dielectric element used in an isolator, and for then assembling the dielectric element with other components to complete the isolator. The dielectric element is first sensitized and activated so that a subsequently applied plating will adhere thereto. The end faces of the dielectric element are then covered with a plating resist, and the element is immersed in a metal plating bath to plate the inner and outer circumferences of the dielectric element. Having been plated, the dielectric element and other components of the isolator are assembled within a hollow connector and joined thereto using a solder sheath.

Abstract: A multichannel communications receiver, e.g. a CATV converter, includes a switched filter for reducing third order intermodulation distortion by limiting the number of channels processed by the receiver. In a preferred embodiment, the filter is switchable between a highpass and a lowpass configuration by a control signal supplied to two switching diodes. The input and output of the filter are coupled by a mutual inductance which partially compensates for the effect of parasitic inductance at higher frequencies.

Abstract: A method is disclosed for the optical alignment of a projection television system having a bank of three light projection means for projecting into coincidence red, green and blue images to form a composite color image in space. The light projection means which are located off the projection screen axis project purposely distorted off-axis images effective to substantially compensate, upon projection, for the non-linear magnification distortion of the image resulting from the off-axis location. The method of optical alignment comprises replacing the cathode ray tubes of the light projection means with lamp means. A graticular geometrical analog of each of the projected images is interposed between the lamp means and a projection lens means.

Abstract: A curvilinear, semi-rigid paper guide for a bi-directional line printer mounted on a platen which provides a surface that bears against the moving print head as the print medium passes between the print head and the paper guide is disclosed. By adjusting the curvature of the paper guide, differences in the distances between adjacent drive sprockets of upper and lower print medium drive mechanisms may be compensated for thus ensuring the printing of straight, parallel and unskewed character lines. In addition, the present invention may be used in a line printer having a single print medium drive mechanism to compensate for nonlinearities in and non-parallelism between the surface of the platen and print head movement.

Abstract: A transformer bobbin is described for holding one or more tapped windings so as to present a low profile. The bobbin includes a coil form which supports the windings and which carries at its ends an upper flange and a lower flange between which the windings are disposed. A plurality of spaced apart fingers are formed at least on the lower flange by slots which extend to the periphery of the lower flange. A terminal strip is carried by the lower flange beneath the fingers so that tap loops from a winding may each be passed through one of the slots and then to the terminal strip where each loop may be joined to an external lead.

Abstract: A television receiver comprises a television system energized by the powerlines of a commercial power grid, a telephone network access system including a microphone disposed in close proximity with the audio speaker of the television system and a remote control system enabling the receiver to be operated in a television mode or a telephone mode. The television receiver according to the invention is characterized by having an annunciator/intercom enabled for operation by the remote control system. In the annunciator mode, the audio section of the television system is disabled and the microphone is connected through a radio-frequency signal transmitter to the power lines for generating a radio-frequency signal for local transmission. A frequency-modulator is included for modulating the radio frequency signal.

Abstract: A pulse code modulated (PCM) infrared (IR) remote control detector/decoder with improved noise immunity particularly adapted for use with a television receiver is disclosed. The IR pulses are modulated by means of a high frequency clock signal in translating the transmitted signal to a higher frequency, more noise immune portion of the IR spectrum. After receipt of the transmitted signal by a signal detector, the high frequency modulation is removed from the pulses which are then decoded. Under the control of a microcomputer, the decoder looks for the start data bit and, if received, the subsequent control instructions. When the data transmission has been decoded, the microcomputer activates the appropriate control outputs to the television receiver's tuner system to achieve the desired control function.

Abstract: A remote control system for a television receiver includes a transmitter and a receiver, the transmitter being adapted for transmitting a single word multibit code identifying a selected function of the television receiver. Each bit of the transmitted multibit code comprises a first occurring data signal representing a selected logic state followed immediately in time succession by a second occurring data signal representing the complementary logic state, the first and second data signals comprising a single pulse representing a first logic state or a grouping of at least two relatively closely spaced pulses representing a second logic state, whereby each transmitted bit comprises the same number of pulses. The remote control receiver includes apparatus for testing the parity relationship of the first and second occurring data signals of each bit of the received multibit code and for controlling the selected function in response to each tested bit being characterized by a condition of parity.

Abstract: A system for correcting for vertical off-axis optical projection distortions in a projection television is disclosed. In a projection television wherein the image projection axis is obliquely disposed in the vertical direction relative to the projection screen axis, a system for correcting for video image distortion caused by this configuration involving modulating the vertical size input is disclosed. A vertical rate correction signal is developed from the vertical output circuit and provided in a feedback arrangement to a sawtooth wave signal generating circuit for regulating electron beam vertical sweep in a projection television CRT, or CRT's. By decreasing CRT electron beam vertical sweep rate across that portion of the projection screen where the video image is vertically stretched and increasing the vertical sweep rate for the vertically compressed portion of the video image, a linear, distortion-free image is presented on the projection screen.

Abstract: An acoustic surface wave multiplexing filter is described having two signal processing paths, one for each of two possible input signals. Each processing path includes an input transducer, a multistrip coupler, and an output transducer. To save substrate area, the multistrip couplers are formed on the substrate in a position of side-by-side overlap with each other.

Abstract: A character generator driven by a microcomputer and providing latched outputs is disclosed. Flexibility in character size and character array positioning on the video display is provided for in this 60-character display generator integrated circuit. A plurality of latched outputs permits the character generator to perform additional functions while reducing the number of dedicated microcomputer outputs required to perform these and similar functions. The character generator is particularly adapted for use in a television receiver where characters are displayed on the face of the cathode ray tube.

Abstract: A method and apparatus are disclosed for altering the exposure time of a master timer in a CRT light house to accommodate masks having different aperture sizes. For each expected aperture size, an exposure time modifier is pre-stored, the aperture size of a mask is sensed, and the modifier corresponding to the mask's aperture size is automatically selected. The selected modifier is used to alter the rate at which the master timer times out so as to provide an exposure interval appropriate for the mask being processed.

Abstract: An article of manufacture is disclosed for use in a projection televison system. A cathode ray picture tube has a face panel with a rearwardly extending skirt and a window for receiving a cathodoluminescent imaging screen. The tube has a seal land which defines a plane whose normal makes a non-zero acute angle with respect to the axis of said window. The article is for use in a system having a cathode ray picture tube whose projection optical axis is on the axis of a remotely located viewing screen, and at least one displaced axis cathode ray picture tube; that is, a tube whose projection optical axis is displaced from the axis of the viewing screen by a non-zero acute angle. The method according to the invention provides for compensating for the non-linear magnification distortion of the projected image caused by the displacement of the tube off the viewing screen axis.

Abstract: A television receiver start-up circuit wherein the conventional start-up transformer is eliminated by initiating horizontal output circuit operation directly from the unregulated B+ driven horizontal driver transformer is disclosed. An astable multivibrator energized by the line referenced unregulated B+ power supply provides a pulsed output to the horizontal driver transformer for initiating oscillation of the horizontal output transistor in initiating television receiver sweep operation.Multivibrator operation is timed out following application of the unregulated B+ thereto for termination of the start-up signal and operation of the horizontal drive circuitry by the television receiver's line isolated power supply in sustaining television receiver operation.

Abstract: Improved mounting and implosion-protection means and method are disclosed for use in a cathode ray tube having a substantially rectangular glass face panel with a rearwardly extending skirt. A first tension band has a predetermined relatively wide width for compressively inwardly loading the panel at a tension level completely effective to protect against implosion. Four mounting brackets, one at each corner of the panel for mounting the tube, have a rearwardly extending foot. A second tension band substantially narrower than the first band circumscribes and overlays the first band. The second band is tensioned at a level 55 to 78 percent of the tension level of the first band for capturing and compressively holding each bracket foot against the first band. The effect according to the invention is such that the tension level of the second band is effective to retain the mounting brackets, but ineffective to deleteriously interfere with the implosion protective tension exerted on the panel by the first band.

Abstract: A television/telephone loudspeaker system is disclosed wherein feedback oscillation caused by having a speaker phone system simultaneously in the transmit and receive mode is minimized. Improved separation of transmit and receive signals is accomplished by microprocessor-controlled dynamic balancing of a bridge network coupled to a telephone isolation transformer to which the incoming and outgoing calls are provided. In addition, by microprocessor sampling of the television receiver's loudspeaker drive voltage from the telephone input line, dynamic proportional attenuation of microphone gain (AGC) is digitally accomplished in simulating full duplex operation. Bridge balancing is accomplished by means of test signals output by the microprocessor during quiet periods with various other audio signal refinements, such as room background noise cancellation, available with the constant monitoring of the microphone signal.

Abstract: Quick-release means are disclosed for use in a television receiver having a molded plastic cabinet with an access opening in the back. The cabinet includes a removable back panel for covering the opening. Quick-release means for attaching the panel to the cabinet back comprise flexible molded extensions of the cabinet include the following. A pair of face-to-face catch means have a projecting flange on each face for flexing into mutual engagement. The catch means include a first member of the pair extending from a flexible edge of the cabinet and a second member extending from the back for joining in snap engagement. A pair of guide means extending from the back panel and spaced on either side of the second member have a taper for guiding the panel and the catch means into sliding engagement. The taper also provides for exerting pressure on the flexible edge to inhibit disengagement.