Abstract: The invention relates to improvements to the operation of a broadcast data receiver (BDR) and, in particular, to the provision of a video data amplifier and driver circuit for the processing of a received video data signal. The circuit includes a means for generating at least one compensatory value and preferably a multiplication factor. The compensatory value is added to the received video data signal as it passes through the circuit to form a combined signal. The combined signal can also be multiplied. The level of the compensatory value can alter with reference to changes in the environment of the operation of the circuit so as to take into account and minimise changes affecting the operation of the circuit and on the video signal.

Abstract: An input stage for a video receiver includes a variable gain amplifier, an analog-to-digital converter for sampling a video signal and a digital processing unit for processing digital samples of the video signal. An analog regulating circuit sets an input potential at an input of the variable gain amplifier. A differential architecture is used for the variable gain amplifier and the digital analog converter. A conversion circuit between an input coupling capacitor and the variable gain amplifier allows generating the video signal on two channels in antiphase, which are centered on the common mode voltage. Such differential architecture allows reducing the amplitude of analog signals, which is particularly advantageous in the case of a low voltage supply delivering a few volts. In addition, linearity of the video signal processing is enhanced.

Abstract: A circuit arrangement includes at least one adapter circuit (10). which amplifies an analog input signal of a low current (Ii) by an amplification factor (n) into a particularly analog output signal of a higher current (Io). The adapter circuit includes an input, which corresponds to a range of low voltages (Ui); an output (18), which corresponds to a range of higher voltages (Uo); at least one npn transistor current mirror (14); and at least one pnp transistor current mirror (16) arranged in series with the npn transistor current mirror (14), and connected to at least one high voltage source (30), wherein the at least one pnp transistor current mirror amplifies the input signal, which is received from the at least one npn transistor current mirror.

Abstract: A programmable gain amplifier having three separately programmable amplifiers. A programmable transconductance amplifier is followed by a programmable transimpedance amplifier, then a programmable switched capacitor amplifier. In one embodiment, this programmable gain amplifier is implemented in an analog front-end (AFE) circuit. One AFE embodiment provides a coarse pre-gain offset a black reference level sampler, and a fine post-gain offset in the programmable switched capacitor amplifier. In one embodiment, an ADC reference is sampled, and is subtracted directly from the video signal in the switched capacitor amplifier so that the zero level of the video signal is made to correspond to the zero level of the ADC.

Abstract: A multiplexed video signal interface in accordance with the present invention provides a multiplexed component video signal which includes component video signals with OSD data and user-controllable contrast and video gain, along with the ability to individually control such signal components. This advantageously minimizes the complexity of the necessary signal interfaces and allows for greater integration of circuit functions, thereby significantly reducing circuit complexity, size and costs. Also provided is a signal peaking circuit in the form of a variable high pass filter that enhances the magnitudes of the higher frequency signal components of the component video signals and OSD data, thereby providing for sharper edges on the displayed images.

Abstract: An interface circuit 13 is provided for a display apparatus 3 such as a television. The display apparatus 3 comprises a video signal processing circuit 8 for processing a composite video signal to derive color component signals having variable black and white levels; a linear amplifier 10 for amplifying the color component signals; and a display device 4 such as a CRT driven by the output of the linear amplifier 10. The interface circuit 13 is provided to interface the color component signals with a digital signal processor 14. The interface circuit 13 includes a modification circuit 22 arranged to perform a modification of voltage levels of the color component signals and to output the modified color component signals to the digital signal processor 14 via an A/D convertor 18.

Abstract: A method for controlling dissipation in a video amplifier for a display signal. The method comprises the steps of setting a first current for establishing a first gain bandwidth product in the video amplifier. Generating a control signal in accordance with a slew rate of the display signal. Modifying the first current responsive to the control signal such that the video amplifier gain bandwidth product is controlled in accordance with the slew rate of said display signal.

Abstract: A variable gain amplification circuit comprises a signal generator that has an output terminal and is able to vary an output amplitude; a variable capacitor connected between the output terminal and an AC grounded terminal; and a control circuit for controlling the output amplitude of the signal generator, and a capacitance of the variable capacitor. Therefore, unnecessary signals can be attenuated even when the gain is low, and degradation in distortion characteristics in the latter block can be suppressed.

Abstract: An amplifier assembly receives an input signal including multiple frequency channels. A first stage amplifier amplifies the input signal, to produce at an output thereof an amplified first signal including the multiple frequency channels. A plurality of second stage amplifiers have their respective inputs coupled to an output of the first stage amplifier. Each second stage amplifier amplifies the amplified first signal, to produce at its respective output a respective second amplified signal including the multiple frequency channels. The first stage amplifier and the second stage amplifiers are variable gain amplifiers, and are constructed on a common Integrated Circuit (IC) substrate.

Abstract: The invention provides a circuit for controlling a cathode ray tube. The circuit comprises a source of input color signals (Uin(R), Uin(G), Uin(B)) for the primary colors of the cathode ray tube. Output amplifiers are coupled to the source of color input signals and to electron guns of the cathode ray tube. Finally, limiting means are provided to limit the color input signals to a predetermined threshold value. In this way the output amplifiers are prevented from saturation and undesirable smears do not appear on the screen. In an advantageous embodiment the limiting means are realized by a diode biased in reverse direction.

Abstract: The invention provides an audio/video amplifier comprising an AV-signal receiver for receiving the signals from one or more program sources; a post-processing circuit connected with said AV-signal receiver for processing audio/video signals of said program source(s) or controlling the volume thereof; a microprocessor for controlling said AV-signal receiver and said post-processing circuit; an auxiliary power supply for powering said AV-signal receiver and said microprocessor; a main power supply controlled by the microprocessor for powering said post-processing circuit; and a signal identifying/comparing module arranged between said AV-signal receiver and said microprocessor for identifying and comparing input AV signals and outputting the result to the microprocessor.

Abstract: A circuit for driving a cathode ray tube (CRT) with cathode current detection. Specifically, the present invention discloses a CRT driver circuit comprising a push-pull configuration comprising upper and lower stages of darlington paired transistors. In the lower stage, a lower prestage circuit generates a video output signal in response to a video input signal that is amplified to drive a cathode electrode of a coupled CRT. In the upper stage, an upper prestage circuit of transistors drives a voltage divider for splitting a high voltage supply between the transistors in the lower prestage circuit. In both the upper and lower stages of darlington paired transistors, upper and lower output stages of transistors are electrically active only during transient periods of the video input signal. As such, a cathode current from a static test signal can be measured from an output through the lower prestage circuit.

Abstract: An active splitter circuit arrangement includes a first amplification module having a number of first input ports and first output ports. The first amplification module is configured to provide first stage amplification to a received input signal and produce from the amplified input signal a number of output signals, each substantially matching the input signal. Also included is a first gain control device having a number of gain input ports respectively coupled to the first output ports and a gain output port coupled to at least one of the first input ports. The first gain control device is configured to control a gain of the first amplification module. Next, a number of second amplification modules corresponding to the number of output signals has a number of second input ports respectively coupled to the first output ports.

Abstract: A CATV tuner apparatus includes a first low-noise amplifier which amplifies a level of an input signal received at an input terminal, the first low-noise amplifier having an adequately small noise figure to allow the received input signal to be amplified with no substantial degradation of a carrier-to-noise ratio of the input signal. An automatic gain control detects the level of the signal amplified by the first low-noise amplifier and adjusts an amplitude of the signal before passing the signal through the automatic gain control. A band-pass filter eliminates out-of-band signal components from the signal received from the automatic gain control and passes only in-band signal components through the band-pass filter. A second low-noise amplifier amplifies a level of the signal received from the band-pass filter.

Abstract: A programmable gain amplifier having three separately programmable amplifiers. A programmable transconductance amplifier is followed by a programmable transimpedance amplifier, then a programmable switched capacitor amplifier. In one embodiment, this programmable gain amplifier is implemented in an analog front-end (AFE) circuit. One AFE embodiment provides a coarse pre-gain offset a black reference level sampler, and a fine post-gain offset in the programmable switched capacitor amplifier. In one embodiment, an ADC reference is sampled, and is subtracted directly from the video signal in the switched capacitor amplifier so that the zero level of the video signal is made to correspond to the zero level of the ADC.

Abstract: A high resolution, multi-tile video display system is described. The universal display system can effectively produce high-resolution images from data received from both analog devices and digital devices such as televisions, personal digital assistants, and computer systems. Generally, the video display system includes a computer system that receives data from several digital data sources. The computer system generates numerous video signals after processing the data. An interface circuit generates display signals after processing the video signals. The display signals correspond to a fractional portion of the high-resolution image. Several displays receive the display signals. After processing the display signals, the displays jointly produce the high-resolution image.

Abstract: In a method of automatic gain control for both TV and FM radio signals, the TV and FM radio signals are controllably amplified (AGC-AMP) to obtain amplifier output signals, the amplifier output signals are tuner processed (F, MIX, IF-AMP) to obtain tuner output signals, the tuner output signals are applied as control signals (T-AGC) to the controllable amplifier (AGC-AMP), a bandwidth of a thus formed AGC loop being wide enough for a TV channel, and the tuner output signals are narrow-band filtered (CF) to obtain narrow-band filtered signals having a bandwidth substantially corresponding to a bandwidth of an FM radio channel.

Abstract: A beam current detection unit (5) detects the brightness of the image displayed on a screen (10) on the basis of a current J flowing inside a CRT (1). A drive control unit (40) selectively closes and opens the switches (42) and (43) in accordance with the detected brightness. Restriction characteristic against a current (I) flowing in a secondary winding (32) included in an inductor (3) is varied stepwise so that the inductance of a primary winding (31) is controlled. Thereby, the frequency characteristic of the gain of an amplifying unit (2) for amplifying an image signal (Pin) is controlled. The high frequency component of the gain is enhanced for a binary image of a normal display, whereas it is enfeebled for a binary image of a reverse display, for example. Thus, the visual quality of the image is optimized depending on the type of the image.

Abstract: An emitter follower amplifier is coupled between the output of a high voltage video amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the video amplifier that is attributable to the kinescope cathode, socket, spark gaps, and related stray capacitances. A secondary undesired capacitance loading of the video amplifier is effectively reduced by regulating the collector-emitter voltages of the emitter follower output transistors at substantially constant values thereby improving parameters such as slew rate and bandwidth of the overall video display system. Nonlinear circuitry in the follower circuit facilitates accurate AKB current sensing and provides simplification of the voltage regulation circuitry. White limiting circuitry is included within the video amplifier for reducing excess peak white drive that results in objectionable smears.

Abstract: Video amplifier circuits and cable/video distribution modules including video amplifier circuits are provided. The video amplifier circuits include a first stage amplifier having a high signal gain and a low noise figure and having an input coupled to a video input signal and an output. A second stage amplifier having a high output power and a low distortion has an input electrically coupled to the output of the first stage amplifier and an output. A splitter circuit has an input coupled to the output of the second stage amplifier and a plurality of outputs.

Abstract: A video pre-amplifier for increasing OSD signal colors in a display device and a method thereof includes an OSD interface block, a video signal amplifying block, an IIC bus control unit, and an intensity control unit. An OSD interface block receives the R, G, and B OSD signals, modifies, or levels, the R, G, and B OSD signals in response R, G, and B control signal, and outputs the leveled R, G, and B OSD signals. A video signal amplifying block synthesizes the leveled R, G, and B OSD signals with the R, G, and B video signals, respectively, amplifies the synthesized signals, and generating R, G, and B output signals. An IIC bus control unit controls the interface between a microcontroller and the video signal amplifying block in the display device and generates a predetermined mode signal. An intensity control unit generates the R, G, and B control signals based on combinations of bits of the mode signal and a predetermined intensity control signal.

Abstract: A system and method for predistorting a signal which is to be amplified by a non-linear amplifier. The system and method uses additional predistortion circuits to eliminate the predistortion caused by amplifier input circuits and amplifier output circuits. In one aspect of the invention, the system and method uses a frequency response and phase corrector circuit to modify the amplitude versus frequency of the signal independent of phase.

Abstract: A beam current detection unit (5) detects the brightness of the image displayed on a screen (10) on the basis of a current J flowing inside a CRT (1). A drive control unit (40) selectively closes and opens the switches (42) and (43) in accordance with the detected brightness. Restriction characteristic against a current (I) flowing in a secondary winding (32) included in an inductor (3) is varied stepwise so that the inductance of a primary winding (31) is controlled. Thereby, the frequency characteristic of the gain of an amplifying unit (2) for amplifying an image signal (Pin) is controlled. The high frequency component of the gain is enhanced for a binary image of a normal display, whereas it is enfeebled for a binary image of a reverse display, for example. Thus, the visual quality of the image is optimized depending on the type of the image.

Abstract: Electronic circuit comprising a first and a second current mirrors, an upstream active element arranged between an input of the first current mirror and an input of the second current mirror, each current mirror being provided with an output. The circuit comprises a first current source arranged in parallel with the input of the first current mirror and a second current source arranged in parallel with the input of the second current mirror, so that the current delivered to the active element is equal to the output current of each current mirror and that the input current of each current mirror is less than the current delivered to the active element by the input of each current mirror and by the associated current source.

Abstract: A method of broadcasting controlling data streams and remote receiving apparatus for using the same are disclosed. A viewer-channel-to-broadcast channel (VCBC) map is employed to map one or more controlling data streams to one or more channels. The VCBC map is stored in memory. When a user tunes to a channel, the VCBC map is checked to determine if a controlling data stream is associated with the tuned channel. The VCBC map is periodically updated and broadcasted.

Abstract: A video control circuit controls the gains for red(R), green(G), and blue(B) color video signals inputted to a monitor, the brightness and contrast of a video display on the monitor, and the bias of a cathode ray tube within the monitor. A microcomputer outputs, in an I2C manner, data for a control signal for controlling contrast, brightness, gain and/or bias. The data are inputted to an I2C data process/PWM signal generation section which converts the data to PWM signal outputs. Rectification sections rectify the PWM signal outputs to provide contrast, brightness, gain and cutoff voltage signals. Only two output terminals of the microcomputer are employed for outputting a clock signal and the data for the control signal so as to control contrast, brightness, gain and bias control signals according to output signals of the variable resistors VR11 and VR12 and a bias/grain control section. A clock signal is generated by the microcomputer in synchronization with the data DATA.

Abstract: Cut-off control circuits implementing DC-coupling and AC-coupling to CRT cathodes can employ the same preamplifier integrated circuits with few additional components. The preamplifier includes a switching unit for receiving control data, generating a control signal according to control data, and outputting the control signal internally or externally. The switching unit provides a control signal internally to an amplification circuit, when the preamplifier operates in a cut-off control circuit having a DC-coupling to a CRT. With a DC coupling the amplification circuit controls a DC bias applied to a CRT cathode. The switching unit provides a bus control signal externally to a bias circuit, when the preamplifier operates in a cut-off control circuit having an AC-coupling to a CRT.

Abstract: A video pre-amplifier includes an input stage and an output stage. In one embodiment, an on-screen display signal is provided to the output stage, and a control signal is asserted when the on-screen display signal is active. With respect to a video output signal, both the gains of the input stage and output stage are adjusted when the control signal is asserted. In one embodiment, the control signal is generated by a comparator within the output stage.

Abstract: The present invention makes it possible to prevent feedback loops from causing oscillations in clamp circuits. When a video signal is input through a capacitor into a first inverting input terminal of an operational amplifier, the output terminal tends to reach a high level because the potential of the first inverting input terminal is lower than the potential of the non-inverting input terminal to which the black level reference signal is input. Thereby the NPN transistor whose base is connected to the output terminal is turned on to charge the capacitor. When the charging of the capacitor approaches completion, the potential of the first inverting input terminal becomes higher than the potential of the second inverting input terminal.

Abstract: A video signal distribution system comprises an interface device and video signal input means for receiving TV signals on broadcast channels connected to the interface device. A plurality of video appliances and a plurality of TV sets may be connected to the interface device such that the television sets are arranged to be remote from the plurality of video appliances. A person using the system has a remote control device that may be actuated to emit signals for selecting channels for viewing and to control the video appliances. Each of the television sets includes a repeater arranged to receive the control signals from the remote control device and form corresponding electrical control signals. The interface device receives the electrical control signals corresponding to a selected TV set and directs electrical control signals to a selected one of the plurality of video appliances to provide video signals to the television sets.

Abstract: A computer video signal distributor receives as inputs the video signals of a computer, and then processes and distributes these video signals to a plurality of monitors. The computer video signal distributor includes three transistor common based voltage amplifying circuits for inputting red, green, blue video signals of the computer respectively, then amplifying these video signals for outputting. Three sets of transistor emitter follower current amplifying circuits are provided for connecting respectively with one of the outputs of the three voltage amplifying circuits, and provide sufficient frequency response for inputted video signals, and distributing the inputted video signals according to the number of monitors. A synchronous signal buffering device is provided for receiving synchronous signals of the computer, and generating a plurality of sets of synchronous signals according to the number of the monitors.

Abstract: A distribution amplifier (210) for a cable television system (100) includes an output gain stage section (215) for receiving an input signal from a cable head end section (105). The output gain stage section (215) includes multiple active amplifier circuits (225, 230) for amplifying the input signal to generate main and auxiliary outputs that are processed by a radio frequency (RF) detector (255) having at least a first detector circuit (300) for processing the main output to generate a first voltage and a second detector circuit (305) for processing the auxiliary output to generate a second voltage. Further included in the distribution amplifier (210) is a status monitor (260) coupled to the RF detector (255) for converting the first and second outputs to first and second digital values and transmitting the first and second digital values. In this manner, an indication of a system or amplifier malfunction can be provided.

Abstract: An induced AC power source video amplifier includes a signal amplifying circuit, a transformer, and a plastic material shell. One end of the transformer is connected to a metal AC line input prong, and another end is connected to supply power to a signal amplifying circuit. The signal amplifying circuit and transformer are fixed to the plastic material shell so that the metal prong projects to the outside of the shell. The shell further includes input and output terminals and selective switches, including a gain select switch and an input select switch.

Abstract: A tap for delivering electrical power and video signals to subscriber substations includes an input coupling module for coupling a main video signal and a main power signal from a cable conductor to the tap. Means are provided for generating a subscriber video signal and a subscriber power signal by extracting portions of the signals from the main cable. The subscriber video signals and subscriber power signals then are transmitted to subscriber substations. Communication devices in the subscriber substations can be powered by the subscriber power signal in the absence of electrical power from a power utility.

Abstract: An amplification circuit comprising a device for compensating for its input current. The amplification circuit includes an amplifier and a capacitor located on the input side of the amplifier. The input-current compensation device consists of a current generator, generating a current Ig, a switch and a device for measuring the average current charging or discharging the capacitor during the time that the switch is open. The current Ig is such that: Average current=Ia-Ig, where Ia is the input current of the amplifier. The value of the average current is close to zero. The value of the current Ig which the current generator must output, so as to make the average current close to zero, is calculated using the device for measuring the average current. The invention particularly applies to a circuit for restoring the DC component of a video signal.

Abstract: A switching circuit for a television set is coupled to the television microprocessor and associated power supply on one end, and to the standby power supply portion of a T-chip on the other end. The T-chip is not powered during the "off" times of the television thus reducing the power consumption of the circuit. The switching circuit operates to enable the standby power supply of the T-chip upon receipt by the microprocessor of an "on" command after which the T-chip will enable the horizontal drive circuits upon the receipt of a further "on" command.

Abstract: An automatic gain controlling circuit and a high-definition television signal receiving apparatus includes an input terminal for receiving a signal including first and second signal components creating interference, a first automatic gain controlling amplifier for amplifying the received signal and providing an amplified output signal, a filter for selectively passing a signal portion in a predetermined band of the amplified output signal from the first automatic gain controlling amplifier, and a second automatic gain controlling amplifier for amplifying the signal portion passed by said filter and providing amplified output signal portion.

Abstract: A video amplifier includes three amplifier circuits (TR, TG, TB) for the red, the green and the blue signals which are each provided with a different feedback signal which changes value when the signal exceeds a certain threshold, by a feedback resistor circuit having two cascade-arranged resistors (R4R in cascade with ?R1+R2+R3!), with their central junction being connected by a diode (Tth) to a fixed voltage (DZ). The ratio value between the two cascade-arranged resistors is different between the amplifier circuits, and moreover, a part (R1 or ?R1+R2!) of the resistor at the base of a cascade arrangement of resistors may be common for several amplifier circuits.

Abstract: Apparatus for processing analog image signals comprising:a plurality of analog image signal channels, each channel including a variable gain amplifier and a high speed video op amp connected to the variable gain amplifier, the op amp having an output and a disable/enable feature, wherein the outputs of the op amps of the plurality of signal channels are connected to a common output; andcontroller for controlling the plurality of signal channels so that only one channel is operable and all other channels are inoperable by setting the gain of the variable gain amplifier of the operable channel to the proper gain and by enabling the op amp of the operable channel and by setting the gains of the inoperable channels to a minimum and by disabling the op amps of the inoperable channels.

Abstract: A more rapid charging of an integrating capacitor of a PLL is provided when large frequency changes are desired. In one embodiment, the phase locked loop (PLL) circuit sinks or sources current to charge or discharge the integrating capacitor. A threshold voltage proportional to a current through the capacitor turns on a circuit which sinks or sources more current of the proper polarity to the integrating capacitor from an external source until a PLL lock is achieved. Once the lock is achieved, if a small correction current is required by the PLL, the small correction current is below a threshold required to actuate the augmenting circuit, and the PLL loop behaves in the usual manner as if the augmenting circuit were not present. In another embodiment, the integrating capacitor is reduced in value by switchably connecting a second capacitor in series with the integrating capacitor so that the total reduced capacitance of reduced value can be charged more quickly.

Abstract: A white clip circuit, formed as an integrated circuit, includes a negative impedance converter which in use is operative to increase the sensitivity of an inverting long-tailed pair of transistors adapted to invert the signals and feed them back to the input in order to control the clip level and to enable it to be effective at a relatively low level.

Abstract: The present invention relates to a complementary transistor circuit and an amplifier using it, and, in particular, to a video amplifier for amplifying video signals and a high-definition CRT display device. In amplifying inputted video signals by using a multiplexer, a gain controller and a current mirror amplifier, each element circuit is formed by using complementary transistor circuits. Circuit simplification is thus attained. In addition, higher precision and band broadening has been realized owing to adoption of a current operation. Further, the present invention makes it possible to eliminate direct feedback from the high voltage output completely by providing a low-voltage output circuit for feedback having a similar relationship with respect to the high-voltage video output stage of the video amplifier, thereby performing negative feedback via a sample-and-hold circuit. This also serves to broaden the bandwidth and reduce power dissipation.

Abstract: A differential transconductance amplifier having a fixed value of differential transconductance provides a video output signal current directly proportional to the transconductance of the amplifier and to a difference between first and second differential video input signals supplies thereto. A pair of buffer amplifiers couples the video input signals to respective inputs of the differential transconductance amplifier via respective diode switches which provides Vber protection for the buffer transistors and provides bus isolation under power down conditions. An output circuit regulates the output voltage of the differential transconductance amplifier at a substantially fixed voltage and converts the output signal current to an output signal voltage. Advantageously, the receiver provides very accurate signal gain control unconditional stability, a wide common mode input voltage range, avoids the need for stand-by power and will not load the input bus under power-down conditions.

Abstract: A wide-band amplifier circuit includes first to eighth transistors, a plurality of resistors, a capacitor and an output terminal.

Abstract: A complementary push-pull emitter follower amplifier is coupled between the output of a high voltage driver amplifier and the cathode of a kinescope for reducing the effective capacitance presented to the driver amplifier that is attributable to the kinescope cathode, socket, spark gaps and related stray capacitances. A secondary undesired capacitance loading of the amplifier attributable to the collector to base capacitances of the follower amplifier is effectively reduced by regulating the collector emitter voltages of the push-pull follower output transistors at respective substantially constant values thereby improving parameters such as the slew rate and bandwidth of the overall video display system.

Abstract: A high bandwidth video output amplifier circuit suitable for driving a cathode ray tube for printing high resolution images on photographic stock with good tonal reproduction includes a high voltage amplifier comprising an emitter follower amplifier with a constant current collector load circuit inputing to an emitter follower buffer current amplifier circuit which drives an output load device such as a cathode ray tube. The constant current collector load provides desired high amplifier gain. A negative feedback path is coupled from the buffer output to the input of the high voltage emitter follower amplifier circuit via an intermediate emitter follower buffer at the input to the voltage amplifier transistor. The feedback provides stable, controlled overall voltage gain and the intermediate buffer amplifier isolates the video input and feedback path from the collector-base Miller capacitance of the voltage amplifier transistor thereby providing a significant extension of the amplifier bandwidth.

Abstract: In a projection television system, a blue phosphor roll-off compensation network is included in the emitter circuit of a common emitter configured transistor comprising the driver amplifier for the blue cathode ray tube. The roll-off compensation network includes a voltage divider connected between the emitter of the common emitter configured transistor and a source of a bias voltage, and a second transistor having its base connected to a point within the voltage divider and its collector-emitter path connected in series with a gain changing resistor between the emitter of the common emitter configured transistor and the source of the variable bias voltage. The voltage divider determines the level of drive current at which the second transistor is rendered conductive and thereby the point at which roll-off compensation is applied. The gain changing resistor determines the amount of compensation.

Abstract: Cost effective video clipping circuitry and method achieve lower distortion color television broadcasting. Excess "white" level voltage peaks in otherwise standard (e.g., that of the National Television Standards Committee) color line video signals are clipped by a unique arrangement to prevent over-modulation of an RF broadcast carrier. The circuitry includes amplifier circuitry for substantially amplifying a line video signal above standard levels, diode clipping circuitry for clipping excess white levels from the signal after it has been amplified thereby reducing distortion otherwise caused by an inherent non-linear initial conduction characteristic of the diode clipping circuitry, and attenuator circuitry for attenuating to standard levels the signal after clipping so as to obtain reduced luminance and chrominance distortion.

Abstract: This circuit includes an arrangement which modulates the horizontal velocity of the spot as a function of the video contents with the aid of a supplementary horizontal deflection coil. This arrangement essentially includes a video signal differentiator followed by an amplifier which supplies a current to the supplementary deflection coil. The current generated by the amplifier has a threshold (S) for the input signal, and a quasi-plateau for input signals beyond 25%. The difference between this current and the current which would be generated by a linear amplifier (broken-line curve) is concerned in this case. This difference, for example for an input voltage of 50%, is referred to as reserve (R). A trap filter is inserted upstream of the amplifier in the arrangement, which filter is centered on the chrominance subcarrier frequency and has a depth which is equal to about the value of the reserve.

Abstract: A push-pull circuit formed of transistors drives a peaking capacitor of an amplifier circuit to enhance charge and discharge of the peaking capacitor. This reduces a bias current, resulting in reduction of a power consumption. A feedback impedance is connected to an emitter of a transistor to feed an output signal back to an input of the amplifier circuit as a current signal in a wide frequency range. Thus, a high-power, wideband amplifier is accomplished.