Abstract: A multibit digital threshold comparator is disclosed which comprises a source of a multibit digital input signal representing a signed arithmetic value, and a source of a threshold signal. Means are provided for producing a magnitude representative signal. The magnitude representative signal produced has either the value of the input signal or that of the ones complement of the input signal depending upon the sign of the value of the input signal. A comparator compares the magnitude representative signal to the threshold signal. The comparator performs one of two comparisons depending upon the sign of the value of the input signal. First, if the value of the input signal is of a first sign, then the comparator produces a signal having a first state if the value of the magnitude representative signal is greater than the value of the threshold signal.

Abstract: A sampled data tone control system, applicable for providing audio bass cut and boost control, includes a single variable multiplying circuit for determining the system variable response characteristics. Input samples are coupled to the multiplier which has its output connected to an integrator. The integrated samples are scaled by a constant and combined with the input samples to provide tone controlled signal.

Abstract: An AC line signal of unknown frequency is compared to a signal of known reference to determine the frequency of the AC line signal. Thereafter, the AC line frequency signal is used as a time-base for keeping real time.

Abstract: A tuning system for tuning non-standard frequency RF television signals provided by cable distribution networks and television accessories conducts first and second consecutive searches by changing the local oscillator frequency. The first search is limited to search frequencies corresponding to predictable non-standard frequencies associated with the major cable distribution networks. The second search includes more search frequencies and extends over a wider frequency range than the first. During an auto-programming mode, in which active channels are identified, for memorization in a channel list portion of a memory, only the first search is conducted to minimize the required time.

Abstract: In an automatic gain control (AGC) network in a video signal processing system, a comparator responds to an input control signal for providing an output control signal to an RF tuner amplifier for decreasing its gain below a normal maximum level when the input signal exceeds a threshold value. The operation of the comparator is inhibited beyond a predetermined level of the input control signal, to prevent a false output gain control signal from being developed.

Abstract: An interpolating apparatus for generating a pair of non-identical, interlaced fields from a single stored field of video signal. One of the interlaced fields is generated by adding three-fourths of one line's amplitude to one-fourth of the next line's amplitude. The other interlaced field is generated by adding one-fourth of said one line's amplitude to three-fourths of the next line's amplitude.

Abstract: A degaussing apparatus for a video display includes a degaussing coil and a source of degaussing current. A switching means is coupled to the degaussing coil and to the source for providing a path for degaussing current between the source and coil during a degaussing operation. First and second PTC elements, functioning as degaussing current reducing means, are coupled to the degaussing coil and to the switching means. The switching means produces alternate coupling of the first and second PTC elements to the degaussing coil with respect to successive degaussing operations.

Abstract: A pair of locating washers are applied over the holes in the bottom mounting lugs of the kinescope. The washers have apertures which are precisely referenced with respect to the position of the kinescope screen by using a pair of oppositely-disposed screen locating marks. The TV cabinet, on the other hand, is equipped with a pair of tapered guiding posts on the inside front surfaces thereof, which are similarly referenced relative to the rectangular opening of the cabinet. When the kinescope is loaded into the cabinet, the cabinet guiding posts are received into the kinescope-mounted locating washers to assure registration between the kinescope screen and the cabinet opening. The kinescope is fixedly secured to the cabinet by a plurality of screws.

Abstract: An on-screen character display system includes a tri-state character generator for generating a tri-state character signal having black portions corresponding to the leading and trailing edging portions of the character and a white portion corresponding to the body of the character and an inactive level when no character is to be displayed. To prevent the shielded cable used for coupling the tri-state character signals to video signal processing circuit from remaining charged to the black level corresponding to the trailing edging portion too long thereby creating a disturbing inequality between the widths of the edging portions, an auxiliary driver circuit is enabled to drive the shielded cable toward the inactive level when the character is supposed to end.

Abstract: A variable preemphasis/deemphasis network is disclosed which is coupled between audio input and output terminals. The network exhibits a family of transfer function response characteristics which vary between a full deemphasis characteristic H(f) and a full emphasis characteristic 1/H(f) in response to a control signal and exhibits complementary transfer function response characteristics in response to reciprocal valued control signals. The network includes a signal filter which determines the shape of the transfer function response characteristic, and a gain controlled amplifier which determines which one of the family of transfer function response characteristics is exhibited in response to the control signal.

Abstract: Circuitry for calculating the square root of a binary number iterates the equation E(K+1)=E(K)+(S-E(K).sup.2) where E(K+1) is the current estimate of the square root of the sample S and E(K) is the previous estimate. The value E(K).sup.2 is estimated in order to reduce the complexity of the hardware. An application is described for real time processing of digital audio signals in serial-bit format.

Abstract: A low cost antenna mount is disclosed for mechanically securing an antenna to an electronic device and simultaneously providing assurance of good electrical contact with the input circuitry of the device. An antenna base (1) with a machined groove (2) is inserted through a hole (4) in a molded plastic antenna housing (5). An integral electrical contact and cam follower (7) is secured to the interior of the antenna housing (5). A cam (15) is used for moving the integral electrical contact (7) and cam follower (7) into mechanical and electrical contact with the antenna base (1). The cam follower (7) is formed from a single strip of spring metal and is bent at three places to form a guide (6) for receiving the antenna base (1) as it is inserted into the hole (4) in the antenna mount. The cam follower (7) is biased to follow the inclined surface of the cam (15) as it is rotated to securely lock the antenna base (1) in place and simultaneously make good electrical contact therewith.

Abstract: In a standby power supply for a television receiver, a rectifier arrangement, electrically nonisolated from a source of AC mains supply voltage, develops a first, nonisolated direct voltage that is present during both the on-state and the standby state of an on-off command signal generated by a remote control circuit. The primary winding of a standby transformer is coupled to the rectifier arrangement and to the AC voltage source for developing a second, nonisolated direct voltage of lower magnitude than the first direct voltage. The control circuit of a switched mode power supply is energized by the second direct voltage and is responsive to the on-off command signal for changing operation of the switched mode power supply between a standby mode and a run-mode. An electrically isolated secondary winding of the standby transformer develops a third direct voltage for energizing the remote control circuit during standby.

Abstract: A picture-within-a-picture television receiver includes circuitry for displaying a reduced-size frozen image developed from an auxiliary signal as an inset in the main image. To develop signals representing two fields of the compressed auxiliary image, the system includes circuitry which processes first and second groups of successive horizontal line intervals of one field of the auxiliary video signal to develop signals representing mutually corresponding horizontal line intervals in two successive fields of the compressed auxiliary video signal.

Abstract: A so-called "V.sub.BE multiplier" circuit is used to temperature compensate a semiconductor device with respect to both short term self-heating effects and long term ambient temperature effects. The compensation circuit includes a transistor with a base, an emitter coupled to an operating potential, and a collector coupled to an operating potential. First and second resistors are respectively coupled across the base-emitter and collector-base junctions of the transistor. The values of the resistors as chosen so that a voltage derived from the collector-emitter path of the transistor and applied to the semiconductor device exhibits a temperature coefficient which substantially matches the temperature coefficient of the semiconductor device.

Abstract: A transmitter unit of a remote control system includes a key function display unit for identifying the function of key elements of the transmitter unit at various steps of a control sequence for one or more controlled devices. The memory for storing character-representative information for identifying the functions of the key elements of the transmitter and corresponding function control instructions is contained in the controlled devices rather than in the transmitter unit. This allows for the addition of new controlled device without modification of the transmitter units.

Abstract: The invention relates to a display system using a remote control handunit having "pointing function" capability for moving a cursor displayed on a display screen by changing the angular position of the remote control handunit. Specifically, the individual transmitting transducers of the remote control handunit are driven with signals having a predetermined phase relationship relative to each other such that the resultant phase received by the receiver is indicative of transmitter angular position.

Abstract: A synchronizing pulse separator for a video apparatus provides horizontal and vertical synchronizing pulses from a composite video signal. The sync separator incorporates a compensation circuit that achieves noise immune operation with composite video signals that provide progressive field display and consequently lack synchronization equalizing pulses. The compensation circuit maintains a sufficient bias level on the sync separator transistor during the vertical blanking interval to prevent premature triggering of the vertical deflection circuit due to noise.

Abstract: A local oscillator is arranged in a Colpitts type configuration in which an amplifying device such as a bipolar transistor or field effect transistor having a control electrode (base or gate electrode) is coupled to a first electrode (emitter or source electrode) defining the end of a conduction channel through an oscillation conditioning network conditioning the device to oscillate in a given range and also to a frequency determining network including a first varactor diode responsive to the tuning voltage and an inductance element coupled in series between the control electrode and signal ground, and in which the output is taken at a second electrode (collector or drain) defining the other end of the conduction channel. A range extending circuit including a second varactor diode responsive to the tuning voltage is coupled between the control electrode and signal ground for ensuring that the oscillator operates reliably at both ends of the tuning range.

Abstract: A degaussing circuit for a video display apparatus eliminates residual degaussing current flow during operation of the video display apparatus. A capacitor is connected between coil of the degaussing relay and the source of energizing voltage. Application of the energizing voltage to the relay coil energizes the relay and initiates degaussing of the cathode ray tube of the video display apparatus, and also causes the capacitor to begin charging. As the capacitor becomes charged, the degaussing relay becomes deenergized, thereby terminating degaussing current flow. The capacitor charging time constant is selected to allow sufficient time for degaussing to occur before deenergization of the degaussing relay.