Abstract: A test circuit within a semiconductor wafer that measures a cut-off frequency for a transistor device under test may include a radio frequency source, located within a region of the wafer, that generates a radio frequency signal. A biasing circuit, also located within the region, may provide a current bias setting to the transistor device under test. The biasing circuit receives the radio frequency signal and applies a buffered radio frequency signal to the transistor device under test. The biasing circuit generates a buffered output signal based on the transistor device under test generating a first output signal in response to receiving the applied buffered radio frequency signal. An rf power detector, within the region, receives the first output signal and the radio frequency signal, and generates an output voltage signal, wherein the cut-off frequency of the transistor device under test is determined from the generated output voltage signal.

Abstract: Circuit with a switch-off device for the operation of light sources The invention relates to a circuit with a switch-off device for the operation of light sources (Lp), have the following features: a self-commutated half-bridge inverter having a series circuit of an upper electronic switch and a lower electronic switch (T1, T2), which are joined at a half-bridge midpoint (M) and are connected between a supply voltage (+) and a ground potential, a start capacitor (C3) which is joined via a trigger element (DIAC) to a control electrode of the lower electronic switch (T2), and a switch-off device having an input (E) and an output, which are configured and connected so that they discharge the start capacitor (C3) if a switch-off signal is applied to the input (E). The switch-off device contains a time delay.

Abstract: A circuit for driving a cathode ray tube (CRT) with frequency compensation. Specifically, the present invention discloses a CRT driver circuit comprising a cascode gain stage for amplifying an input voltage. A cascode push-pull output stage generates a video output signal from the input voltage at an output node. The video output signal drives a coupled CRT and corresponding CRT cathode. A biasing node within the push-pull output stage has a biasing voltage that is always higher than the output voltage of the video output signal. Electrodes of a vertical-integrated PNP transistor are adaptively coupled to the biasing node, output node, and the cascode gain stage to provide two parallel feedback paths for frequency compensation without any cathode current leakage. As such, a current detection circuit accurately measures cathode current from a CRT that is driven by the CRT driver circuit.

Abstract: A cutoff adjustment method of a CRT using a Hi-Gm tube is proposed as well as a problem that luminance of a display screen is changed by a fluctuation of a Gm voltage to be applied to a Gm electrode in relation to fluctuations of currents flowing into the Gm electrode and a G2 electrode is solved. On this occasion, the cutoff adjustment method of the Hi-Gm tube sets such that a Gm voltage value of a Gm electrode voltage source and a black level bias voltage value applied to a cathode for displaying a black level agree with each other. Further, the CRT display device having the Hi-Gm tube is constituted such that it is provided with a voltage detection circuit in an output side of the Gm electrode voltage source for measuring a fluctuation of an output voltage from the Gm electrode voltage source to keep the Gm voltage constant by a feedback from the voltage detection circuit.

Abstract: A CRT display apparatus is disclosed. The CRT display apparatus includes a CRT having an electron gun whose electrodes for controlling an electron beam are applied with voltages from their respective voltage sources specifically designed to supply an electrode current, and is capable of automatically ceasing a discharge that has occurred under fault conditions between any electrode within the electron gun and the cathode or an anode of the CRT.

Abstract: An AKB interface apparatus in a display system (10), includes a video signal processing IC (12) having outputs coupled via respective kinescope driver ICs (18,20,22) to respective kinescope cathodes (K1,K2,K3) for display of a color image, the signal processing IC having an input 27 for receiving an AKB input signal, the driver ICs having respective outputs (28,30,32) providing respective cathode current indicating signals (RP,GP,BP) An interface circuit (100) couples the cathode current indicating signals to the AKB input of the signal processing IC. The interface circuit comprises a load circuit (110) for generating a load voltage (Vo) in response to at least one of the cathode current indicating signals. A leakage correction circuit (130), responsive to said load voltage (Vo), feeds back a leakage correction current (Io) to the load circuit.

Abstract: An external magnetic field correction device capable of preventing malfunctions of the external magnetic field correction device due to operation of a degaussing circuit by judging that an abnormality has occurred when an output of an external magnetic field detector is not less than a predetermined value and interrupting offset adjustment process accordingly, and that is capable of limiting irregularities of offset current in operational current of the magnetic field correction device to predetermined value or less by adjusting an offset value as to make correction current to be supplied to an external magnetic field correction coil when an external magnetic field around a CRT is zero to a regular value or less.

Abstract: Video signals to be displayed are applied via a video driver amplifier to the cathode electrode of a kinescope. A beam current sensor, also coupled to the cathode electrode, provides a beam current indicating signal. An AKB regulator, responsive to the beam current indicating signal, supplies a black level correction signal to the driver amplifier for regulating the black level of images displayed by the kinescope. A screen grid supply system is provided for controlling the G-2 (screen grid) voltage of the kinescope as a predetermined function of the black level correction signal thereby forming with the AKB regulator a dual feedback loop for providing black level regulation by both the driver amplifier and the screen grid thereby maximizing or extending the overall black level control range.

Abstract: A pair of current sources, each having a high output impedance, are coupled to a pair of first and second inputs of a differential input stage of a vertical deflection amplifier. An output of the amplifier is coupled to a vertical deflection winding. A current sampling resistor is coupled to the first input via a first resistor. The second input is coupled via a second resistor to a terminal of the sampling resistor that is remote from the first resistor. The first and second resistors are matched resistors for providing differential driving.

Abstract: Known display devices include a video signal processing circuit with a black level setting circuit. This black level setting circuit measures the black level of the video signal, for example, during the field retrace interval by making use of an extra output of the video output stage. However, the measured black level has a line-frequency interference component which is caused by a parasitic capacitance in the display tube. The line-frequency interference component is fully compensated for by coupling one side of a secondary winding of a transformer, required for the focusing voltage to be generated, to a first capacitor, the other terminal of which is connected to the measuring input of the black level setting circuit, and by coupling at least a second and a third capacitor across the secondary winding of the transformer.

Abstract: A first transformer is coupled to a deflection yoke and coupled to a derived secondary voltage source for driving a load, for example, for generating an ultor voltage. An on/off switch is responsive to an on/off signal. A second transformer has a primary winding coupled to the switch and coupled to a voltage source and has a secondary winding coupled to the first transformer. A first sampling circuit generates a first feedback signal indicative of current flowing from the secondary winding to the first transformer. A first safety circuit responsive to the first feedback signal controls the effect of the on/off signal on the switch when the current flowing from the secondary winding to the first transformer exceeds a threshold, by limiting the on time of the switch to limit the peak value of the current. A second sampling circuit generates a second feedback signal indicative of the ultor voltage.

Abstract: The disclosure relates to cathode-ray tubes that have to be used at a low level of luminance. The cut-off voltage of the tube is modified by using two servo-control loops, the first one as a function of the value of the cathode current and the second one as a function of the luminance value of a zone that is located outside the operational image of the screen and consists of a particular luminophore. Selector means are used to change over from one loop to the other and vice versa as a function of the values of the cathode current and of the luminance of the zone with respect to certain predetermined thresholds.

Abstract: A vertical deflection ramp voltage is generated by the charge and discharge of a resistor capacitor combination. The voltage ramp is coupled to an amplifier which drives a current through a deflection coil producing a magnetic deflection field. The ramp voltage produced by the resistor capacitor combination has an inherent exponential shape which is linearized to prevent vertical linearity errors in the deflected electron beam. Linearization is achieved by multiple feedback paths which couple the amplifier output voltage and a voltage sample of the deflection coil current to the ramp forming resistor. These feedback signals are of a polarity such to establish a constant voltage across the resistor which consequently produces a constant current flow through the resistor. Hence with constant current flow in the resistor, a linear voltage ramp is produced across the capacitor and exponential deflection cramping is avoided.

Abstract: A driver stage of a horizontal deflection output transistor includes a transformer having a first winding coupled to a collector of a second, driver transistor responsive to an input signal at a horizontal deflection frequency. A second winding of the transformer is coupled across a base-emitter junction of the output transistor and a third winding is coupled to the emitter of and in series with the output transistor. The third winding couples the emitter current to the base of the output transistor for supplying a substantial portion of the base current during the second half of trace. A feedback network is coupled between a trace capacitor coupled to a horizontal deflection winding and the collector of the driver transistor for preventing abnormal steady state operation in the output transistor.

Abstract: A vertical deflection circuit for a CRT display device comprises a first negative feedback circuit for detecting a vertical deflection current flowing through a vertical deflection coil feeding it back to a ramp wave generator to thereby stabilize a vertical size of the display image on the CRT screen, second negative feedback circuit connected between the deflection coil to an input of the output circuit for detecting a mean vertical deflection current which is fedback to an output circuit to thereby stabilize a vertical position of the display image on the CRT screen and a controlling circuit for controlling feedback amount of the first and second negative feedback circuits to thereby regulate a vertical size and a vertical position of the display image on the CRT screen variably.

Abstract: A signal generator which generates an yoke signal for application to a horizontal yoke of a cathode ray tube (CRT) is presented. The signal generator receives a dc signal which indicates the width of the horizontal scan lines of the cathode ray tube and receives a pincushion correction signal. The signal generator includes a voltage source, a yoke current generator, a current feedback network, a summing circuit, an amplifier and a voltage regulator. The summing circuit sums the voltage of the dc signal and the pincushion correction signal. The current feedback network generates a first feedback signal with a first feedback signal voltage proportional to the peak value of current through the horizontal yoke. The amplifier generates a second feedback signal based on the difference in the voltage of the first feedback signal voltage and the summed voltage of the dc signal and the pincushion correction signal.

Abstract: A vertical deflection circuit for a CRT tube, with a so-called Mirror integration circuit, has an integration arrangement with a resistor and a capacitor, and a first amplifier for amplifying saw-tooth wave by the integration arrangement with a deflection coil coupled with output of the amplifier. A first feedback path is located between the deflection coil and the capacitor has been improved by a second feedback path between the deflection coil and input of the first amplifier. The second feedback path provides the sum of the parabolic voltage at the end of the deflection coil which is grounded through a second capacitor and a second resistor, and the saw-tooth wave voltage responsive to the current in the deflection coil to the first amplifier. The second feedback path provides the so-called S-shaped compensation on a screen so that a picture distortion, due to a non-arc face of a screen at peripheral portions, is compensated.

Abstract: A circuit for use in a video display apparatus corrects raster shift due to beam current variations. A horizontal retrace related pulse is applied to the ramp generator for the horizontal deflection phase control circuit, causing the retrace AC zero crossing of the ramp to shift under high beam current conditions. The phase control circuit then shifts the ramp signal to center the synchronizing pulses about the zero crossing, resulting in a raster shift which compensates for the raster shift introduced due to beam current variations.

Abstract: Feedback loops monitor the vertical and horizontal deflection yoke drive voltages of the CRT and separately compare each potential with a voltage which represents full screen deflection. Error voltage resulting from these comparisons adjust the power supplied the yoke to maintain full scale deflection with variations in the frequencies of the vertical sweep or horizontal sync pulses. The feedback loops can be made interdependent so that the smaller one of the two drive potentials determines the size of both drive potentials. In this way the aspect ratio will be maintained irrespective of the changes in the format presented on the screen.

Abstract: A circuit for generating a sawtooth current (I) in a coil (25), the coil (25) being driven during the trace periods of the sawtooth from an amplifier circuit (4, 6, 7, 9, 15) by a current, and during the shortest possible retrace periods, the amplifier circuit being blocked, the coil (25) being included in a resonant circuit (25, 20, 21, 18, 7) which further comprises a capacitor (20), a first (21) and a second diode (18) and a transistor (7). In order to prevent disturbing ringing phenomena from occurring when a retrace period of the shortest possible duration is required, the junction of the capacitor (20), the first (21) and the second diode (18) and the transistor (7) is fed-back via a resistor (23) to a signal input of an amplifier (4) comprised in the amplifier circuit (4, 6, 7, 9, 15), this signal input further being coupled to a terminal (1) for the supply of a sawtooth voltage.

Abstract: An efficient cathode ray deflection amplifier is provided having a selectable scan rate capability, providing sweep rate linearity through the use of a feed back arrangement that also cooperates in a self-adaptive manner with respect to commanding changes in the raster scan rate or display size.

Abstract: A vertical sawtooth generator adaptable for integrated circuit application self-oscillates under control of a latch circuit. A circuit controls the linearity of the charging capacitor ramp voltage. High frequency components of the recurrent ramp occurring due to the retrace discharge current are reduced by controlling the discharge currents. The ramp rate is controlled by a single resistor external to an integrated circuit.

Abstract: Each orthogonal driver channel for the magnet deflection yoke of a conventional CRT includes a simple bifilar wound transformer which is connected so that the deflection current waveform passes therethrough. The transformer effectively minimizes the inherent parasitic capacitance between the two windings of the magnetic deflection yoke as it affects a high frequency input signal presented to the input terminal of the high gain operational amplifier. However, the impedance introduced within the feedback loop of the operational amplifier is minimal with respect to an input signal to either driver channel, and thus no significant distortion is presented to the current waveform driving each winding.

Abstract: A deflection waveform generator uses a low voltage accurate capacitor to integrate the yoke deflection current and derive a parabolic waveform for "S" correcting the basic sawtooth deflection waveform. This parabolic waveform is fed back to the inverting input of a balanced operational integrating amplifier, the inverting input also having the integrating network coupled thereto. The polarities of the signal waveforms at the inverting input are such that the combined signal fed through the integrating network creates a "S" corrected sawtooth yoke deflection current which drives the electron beam in a manner which compensates geometric distortion inherent in the CRT.

Abstract: Improved slew recovery in a composite driving amplifier for driving a substantially reactive load including a feedback loop to the operational amplifier from the load for regulating the output of the amplifier, the composite amplifier has a predetermined resistance R1 in the feedback loop and includes a second feedback loop having a predetermined resistance R2. The second feedback loop extends from the output of the operational amplifier to the negative input and is substantially parallel with the first-mentioned feedback loop. To maximize the recovery of the amplifier from a slew condition, the relationship of R1-R2 should be as follows: ##EQU1## wherein: V.sub.o is the output voltage in the amplifier.Slope, is the slope of the load voltage curve during the overload condition, andDelay represents the period of time it takes the overload operational amplifier to respond to a feedback signal at a given overload condition.

Abstract: A device for displaying variable quantities on the viewing screen of a cathode-ray tube by means of deflection coils which are energized by a number of deflection amplifiers coupled to different supply voltages, the deflection amplifier with the lowest supply voltage serving for signal components with the lowest frequencies and that with the highest supply voltage for the signal components with the highest frequencies. This results in a substantial reduction in power consumption.

Abstract: A vertical deflection amplifier includes a preamplifier having an input at which is applied a DC feedback signal for the stabilization of the amplifier's DC output. In order to assure an undistorted or unattenuated vertical deflection upon initial turn-on of the receiver, a fast-start circuit superimposes a transient voltage on the DC feedback signal. The fast-start circuit allows the amplifier's output to reach its quiescent DC output level in a period of time that is substantially shorter than the time constant of a sampling network from which the DC feedback signal is derived.

Abstract: A high speed driver circuit for the magnetic deflection yoke of an orthogonal channel displaying high speed alphanumeric characters, or the like, includes a first input receiving a stored signal proportional to the derivative of the vector slope component and a second input receiving a positive feedback from the yoke sense resistor. At high frequencies the yoke current is primarily inductive so that the voltage across the yoke is proportional to the rate of change of current through the yoke, hence, this voltage, when properly connected by positive feedback, is also proportional to the derivative of the voltage across the magnetic deflection yoke. By combining this voltage waveform directly within the vector slope signal, the need for an active integrator in the closed loop driving the magnetic deflection yoke is eliminated.

Abstract: A vertical deflection circuit having a vertical amplifier stage bias voltage stabilizing circuit including a differential amplifier circuit which operates only during the retrace period. One input of the differential amplifier circuit receives a D.C. bias voltage and the other input receives the mean voltage of an output signal. The output of the differential amplifier circuit is fed back to a drive stage to stabilize the bias voltage.

Abstract: A television field deflection circuit with a rapidly controllable large linearity. The deflection current is integrated in a first integrator which is followed by a second integrator having an adjustable time constant. The signals integrated once and twice are applied to a difference amplifier, while the signal integrated once is inverted and is adjustable through a feedback circuit. Subsequently a signal combination is formed of a non-integrated signal, a signal integrated once in phase, an adjustable signal integrated once in opposite phase and an adjustable signal integrated twice. The signal combination is fed back to a difference amplifier through which the deflection coil is fed and to which furthermore a sawtooth-shaped signal with a parabolic component is applied.

Abstract: A field output circuit in which for preventing vertical bounce of the picture and of linearity errors a feedback alternating current path is provided which includes a field frequency clamping circuit. In one embodiment the clamping circuit may be formed by the field oscillator constituted as a capacitive sawtooth generator.

Abstract: A vertical deflection circuit including a Miller integrator and a Schmitt trigger circuit in combination to obtain a sawtooth wave signal at an output terminal of the Miller integrator circuit and a vertical deflection coil connected to the output terminal of the Miller integrator circuit to be supplied with the sawtooth wave signal therefrom in which the Schmitt trigger circuit is controlled by a vertical pulse signal for synchronization and the Miller integrator circuit is preferably controlled by a parabolic wave signal of the vertical scanning rate in order to compensate for or correct the non-linearity in the vertical deflection. The circuit configuration is well suited for being formed as an integrated circuit on a single semiconductor substrate.