Abstract: Trilevel sandcastle pulse decoder includes a trio of voltage comparators for comparing incoming sandcastle pulses with reference potentials of respectively different levels. One of the voltage comparators, which is subject to change in operating state in response to appearance of a given level of the sandcastle pulse, is precluded from operating state change in response to the appearance of the next higher level of the sandcastle pulse by control circuitry responsive to the output of a second of the voltage comparators. One of the decoder outputs is developed by logic circuitry responsive to outputs of two of the comparators.

Abstract: A color television receiver includes AKB control circuits, operative during periodically recurring kinescope bias control intervals, for automatically adjusting the cathode biases of the receiver's color kinescope.

Abstract: DC stabilization system for color signal inputs to kinescope drivers of a color TV receiver (of a type employing AKB control) includes four control loops, one serving to adjust DC level of I color-difference signal, one serving to adjust DC level of Q color-difference signal, and two serving to adjust DC level of the Y (luminance) signal. One of the Y-adjusting control loops, employing a voltage comparator enabled only during periodic kinescope bias control intervals recurring at a field rate, is provided with an effective time constant which is short relative to the duration of a line interval. The other of the Y-adjusting control loops, employing a voltage comparator enabled only during backporch blanking portions of line intervals lying outside of the recurring kinescope bias control intervals, is provided with an effective time constant which is long relative to the duration of a line interval.

Abstract: In a system for enhancing horizontal detail of a luminance signal, a horizontal peaking signal to be added to the luminance signal is cored with the depth of coring varied in accordance with a coring control potential. To develop the coring control potential, the input luminance signal is capacitively coupled to the input of a signal translator comprising an inverting amplifier with a frequency selective negative feedback path providing the translator with a low pass characteristic and a signal delay substantially equal to the delay of a delay line employed in peaking signal formation. An additional feedback path is provided by the emitter-collector path of a clamping transistor that conducts in response to sync pulse appearances to readjust the charge on the input capacitor, clamping the sync pulse peaks to a potential selected to establish a desired coring depth for black scene regions. Amplifier gain is set to provide translator output swing establishing a desired minimum coring depth (e.g.

Abstract: A deflection yoke adjustment apparatus for adjusting a yoke on a kinescope comprises independent coil holders for supporting the horizontal and vertical deflection coils of the yoke. Six elongated positioning rods are attached to particular locations on each coil holder. Actuators, for example stepping motors, move selected ones of the rods to cause translation of the coil holders along a vertical, horizontal or longitudinal axis, or rotation of the coil holder about any of the aforementioned axes. The vertical and horizontal coils may be moved independently to provide an optimum kinescope display. The apparatus also comprises coil alignment devices associated with each positioning rod to maintain coil orientation during movement and force limiting means to protect the kinescope against damage during coil movement.

Abstract: A television horizontal deflection system and a switched-mode power supply are provided which share a single sawtooth waveform generator for the generation of delayed deflection signals and delayed power supply gating signals, respectively. The sawtooth waveform generator has an input coupled to receive pulses which are maintained in phase and frequency synchronism with the sync pulses of the video signal. The sawtooth waveform is applied to a comparator in the horizontal deflection system where it is compared with a D.C. voltage resulting from the phase comparison of the sync and flyback pulses to determine the time of delayed generation of the succeeding horizontal deflection signals. The sawtooth waveform is also applied to a comparator in the power supply to determine the time of delayed generation of the succeeding gating signals for the SCR or like device. By selecting a time constant for the phase adjustment between sync and flyback in the deflection system which is smaller (i.e.

Abstract: A signal separation network is provided which accomplishes the functions of a sound take-off network and intercarrier sound trap in a single network. A common detector produces detected composite video and intercarrier sound signals. Circuitry is provided for processing the composite video signal, and a separate circuit is provided for processing sound information. The signal separation network has an input responsive to the detected composite video and intercarrier sound signals, a first output terminal coupled to the input of the video processing circuitry, and a second output terminal coupled to the input of the sound processing circuitry. The network is characterized by a transfer function which exhibits a dominant zero approximately at the intercarrier sound frequency at the first output terminal, which provides trapping of the intercarrier sound signal in the path to the video processing circuitry.

Abstract: In a remote controlled television receiver, the regulator circuit of the main television receiver power supply is made responsive to a remote on/off command signal in order to turn the receiver on and off. A deflection flyback transformer provides operating voltages to the ultor supply and other auxiliary supplies which power such load circuits as audio and vertical deflection. A horizontal output transistor is coupled to a B+ operating voltage terminal of the main power supply through a flyback transformer primary winding. After initiation of the on-state of the command signal, the regulator ciruit rapidly develops a B+ operating voltage. The initially uncharged filter capacitors of the auxiliary supplies act as a low impedance shunt across the flyback transformer primary winding during the start-up interval.

Abstract: A pulse generator is provided which may be advantageously used to produce a deflection drive signal in a television receiver. A capacitor is initially charged to a reference voltage level. Prior to the time at which the output pulse is to be generated, the capacitor is charged from a current source for a known time duration at a first rate. At the end of the charging interval, the capacitor has accumulated a known increment of charge proportional to the charge interval, and a new voltage level is established across the capacitor. The generator is now prepared to produce an output pulse. At a subsequent time, when the output pulse is needed, the capacitor is discharged at a second rate by a second current source. During the time interval that the second current source is discharging the capacitor, an output pulse is produced by the generator.

Abstract: A method of tuning a trap circuit to a desired frequency is provided. A constant amplitude signal is applied to the trap circuit in a progression of successively different frequency increments. The frequency increments cover a frequency range including the desired frequency. The amplitude of the signal, as modified by the trap circuit is detected and stored at each of the different frequency increments. Successive ones of the stored amplitude values are compared until an amplitude difference is found which is greater than a predetermined minimum difference and is of a polarity indicative of an increase in amplitude with the progression, and is a successor of an amplitude difference which is greater than the predetermined minimum difference and of a polarity indicative of a decrease in amplitude with the progression. The frequency at which the inflection point occurs, as indicated by the two-named amplitude differences, represents the null frequency of the trap circuit.

Abstract: A preamplifier is provided which couples a television tuner to a surface acoustic wave (SAW) filter and amplifies the I.F. signals supplied by the tuner so as to overcome the signal losses of the SAW filter. The preamplifier comprises a single transistor, the gain of which may be varied to provide desired gain and noise performance for the entire tuner-SAW filter-I.F. system. The gain of the preamplifier is simply adjusted by changing the values of one or two resistive components. The preamplifier includes a negative feedback path, which stabilizes the preamplifier against temperature variations, presents desired impedances to the tuner and SAW filter, and permits the substitution of a different transistor without the need for extensive readjustment. Means are provided for simply adjusting the biasing of the transistors without adversely affecting any previous gain adjustments.

Abstract: Apparatus is provided for suppressing radio frequency interference radiation at a circuit connection point. The apparatus includes a capacitor having first and second terminals, the first of which is coupled to a substantially planar plate of the capacitor. The first terminal is coupled to the circuit connection point, which may otherwise act as an RFI antenna. The second capacitor terminal is coupled to a point of reference potential for radio frequencies. The capacitor is oriented when mounted so that the planar plate opposes and is substantially parallel to a metallic surface which is at the radio frequency reference potential (e.g., ground). The capacitor suppresses RFI radiation from the circuit connection point by conducting a portion of the RFI energy at that point to the point of RFI reference potential by way of the first terminal, the body of the capacitor, and the second terminal.

Abstract: A differential amplifier is provided, including first and second emitter coupled transistors responsive to an input signal applied to one of their base electrodes, and a current source transistor having its collector-to-emitter path serially coupled between the coupled emitters of the first and second transistors and a point of reference potential. A current repeater circuit is coupled between the collector electrodes of the first and second transistors which comprises a current mirror for replicating the collector current of the first transistor. The current mirror includes third and fourth transistors having respective collector electrodes coupled to the collector electrodes of the first and second transistors, respectively, the base electrode of the third transistor being coupled to the base electrode of the fourth transistor, and a resistor for coupling the emitter electrode of at least one of the third and fourth transistors to a source of supply voltage.

Abstract: A comb filter apparatus is provided with means for equalizing the delayed and undelayed signal levels at the inputs to the adding or subtracting matrix, whereby maximum cancellation and reinforcement of the undesired and desired signals is effected. An input signal is coupled to an additive or subtractive matrix by way of an undelayed signal path and a delayed signal path. The delayed and undelayed signals at the inputs to the matrix are each coupled to a detector by way of a bandpass filter, which pass frequencies at which the combing of the signal is most critical. The detectors detect the levels of the input signals and apply the detected levels as two inputs to a difference circuit. The two signal levels are compared in the difference circuit to develop a gain control signal. The gain control signal is utilized to control the gain of a gain controllable stage which is coupled in series with one of the signal paths thereby equalizing the levels of the input signals to the combining matrix.

Abstract: A network is provided for attenuating the adjacent channel sound carrier signal in a television receiver. First and second trap circuits are serially coupled intermediate the R.F. mixer and the first I.F. amplifier. One of the trap circuits is tuned to a frequency in the vicinity of and above the nominal frequency of the adjacent channel sound carrier, and the other is tuned to a frequency in the vicinity of and below that of the adjacent channel sound carrier. The two trap circuits are mutually coupled to a degree necessary to produce a composite response curve exhibiting a substantially constant level of maximum attenuation in the vicinity of the nominal frequency location of the adjacent channel sound carrier. The trap circuits provide attenuation in excess of that required to eliminate adjacent channel sound carrier interference over a bandwidth sufficient to encompass expected carrier deviation due to frequency modulation, carrier mislocation, and trap mistuning.

Abstract: A selectivity network is provided for a synchronous detector, a reference signal circuit, and an AFT circuit. The selectivity network comprises a first tuned circuit coupled across two terminals of the reference signal circuit and tuned to the desired frequency of the I.F. picture carrier. A second tuned circuit is lightly coupled to the first tuned circuit and is coupled across two inputs of the AFT circuit to provide a frequency dependent phase-sifted reference signal to the AFT circuit. The first tuned circuit includes a trap circuit tuned to provide attenuation about a frequency intermediate the frequency of a sound carrier and that picture signal sideband frequency which, upon detection, results in a video signal corresponding to the intercarrier sound second subharmonic frequency. The trap in the reference signal tuned circuit minimizes quadrature distortion in the reference channel and the resultant harmonic distortion in the video signals, which causes sound buzz.

Abstract: In a color television receiver including a comb filter for separating luminance and chrominance components of a color television signal, a network is included for selectively restoring, enhancing and paring vertical image detail to preserve and enhance vertical resolution in the luminance content of a displayed image. The comb filter provides a combed luminance signal output from which vertical detail signal information has been unavoidably deleted, and a combed chrominance signal output including signal frequency components representative of the deleted detail signal, which are selectively extracted from the combed chrominance signal. Low level detail signals are restored to the combed luminance signal via a first signal processing network which exhibits a prescribed signal restoration gain.

Abstract: A gain controllable circuit suitable for processing vertical detail signal information in a video signal is disclosed. The circuit exhibits a non-linear signal amplitude transfer function wherein different amounts of signal gain are imparted to signals having amplitudes within prescribed ranges. Small amplitude signals subject to restoration are translated with a prescribed restoration gain. Moderate amplitude signals subject to enhancement (peaking), and large amplitude signals subject to paring (amplitude reduction), are controllably amplified without altering the restoration gain characteristic for small signals.

Abstract: In a receiver subject to SECAM signal reception, an FM detector responsive to the received signals has its center frequency tuning switched between one SECAM subcarrier center frequency and the other SECAM subcarrier center frequency. Control of the switching, in response to line rate, burst interval pulses and to half line rate waves from a triggered flip-flop, is such that tuning is different in image portions of successive line intervals, but the same in lead-in burst portions of successive line intervals. A first sampler effects sampling of the detector output only during alternate burst occurrences, while a second sampler effects sampling of the detector output during the intervening burst occurrences. Sampler outputs are supplied to a comparator which provides an output suitable for controlling disabling/enabling of flip-flop to establish correct phasing of the switching of the detector tuning.

Abstract: Circuits are disclosed for processing color encoded video signals, encoded per a format wherein a chrominance signal in the form of a modulated subcarrier is buried in spectrum "troughs" in the midband of a wider band luminance signal, an illustrative use of the encoding format being in video disc recording. The processing circuits serve, in use with composite signals developed during video disc playback, to convert an input composite signal of buried subcarrier format to an output composite signal of NTSC format. Comb filtering is employed to separate buried subcarrier chrominance signal from midband luminance signal components. A heterodyning step preceding comb filtering is performed in a manner substantially precluding "jitter" of played back signals from disturbing accuracy of comb filter separating action, enabling use of a single 1H delay line form for the comb filter and enabling use of a relatively inexpensive, narrowband structure for the single delay line.