Cathode ray beam current control system utilizing variable duty cycle and amplitude modulation

Claim 3

A system as recited in claim 1 wherein said pulse generator means comprises: a circuit having a stable state and an unstable state, having a first output and a second output for respectively producing said first and second pulse trains, and having an input for driving said circuit from its stable to its unstable state; means for applying a signal to said input for driving said circuit from its stable to its unstable state comprising: a capacitor connected to said input circuit, means for applying a feedback current from said first output to said capacitor, means for applying said current to said capacitor, and means responsive to the voltage on said capacitor exceeding a predetermined threshold for driving said circuit from its stable to its unstable state.

Claim 4

A system as recited in claim 1 wherein said pulse generator means comprises: a circuit having a stable state and an unstable state, having a first output and a second output for respectively producing said first and second pulse trains, and having an input for driving said circuit from its stable to its unstable state; means for applying a signal to said input for driving said circuit from its stable to its unstable state comprising: a field effect transistor having gate, source and drain electrodes, means connecting said field effect transistor gate electrode to the input of said circuit, a first transistor having collector, base and emitter electrodes, means connecting said base electrode to said field effect transistor drain electrode, a feedback resistor connected between the first output of said circuit and the emitter of said first transistor, means connecting said first transistor collector to said field effect transistor gate, a capacitor connected between said field effect transistor gate and said first transistor base, and means for applying said current to said capacitor.

Claim 5

A system as recited in claim 3 wherein said circuit comprises: a second and third transistor each having base collector and emitter electrodes, first resistor means coupling said second transistor collector to said third transistor base, means connecting together the emitters of said second and third transistors, means connecting said field effect transistor source to said second transistor base, feedback resistor means connected between said first transistor emitter and said second transistor collector, means for applying operating potentials to the collectors and emitters of said second and third transistors, and means for applying a biasing potential to said third transistor base.

Claim 6

A system as recited in claim 1 wherein said means for generating a current which is a function of sweep speed comprises: a source of an unblanking pulse train wherein pulses in said unblanking pulse train constitute cathode ray tube unblanking signals, a capacitor, a source of potential, means for charging said capacitor from said source of potential, and means for discharging said capacitor during each pulse in said unblanking pulse train to provide a current which is a function of sweep speed.

Claim 7

A system as recited in claim 5 wherein said means for charging said capacitor from said source of potential comprises: a transistor having collector, base and emitter electrodes, means for applying a conductive bias to said transistor base, means connecting said transistor collector to said capacitor, a resistor having one end connected to said transistor emitter, another capacitor connected between said source of potential and the other end of said resistor, means for discharging said another capacitor responsive to the leading edge of an unblanking pulse in said train, and field effect transistor means connected to said capacitor for discharging said capacitor responsive to an unblanking pulse in said pulse train.

Claim 10

In a cathode ray beam storage tube system wherein the cathode ray beam is modulated as a function of video signals and a control current, the improvement comprising: pulse generator means for generating a train of pulses whose duty factor is a function of said control current, means for amplitude modulating the pulses in said train of pulses as a function of said video signals, and means for applying said amplitude modulated train of pulses to said storage tube for modulating the cathode ray beam in response thereto.

Claim 11

In a cathode ray beam storage tube system wherein the cathode ray beam is modulated as a function of video signals and a control current, the improvement comprising: pulse generator means for generating a train of pulses whose duty factor is a function of said control current, means for amplitude modulating the pulses in said train of pulses as a function of said video signals, and means for applying said amplitude modulated train of pulses to said storage tube for modulating the cathode ray beam in response thereto.

Claim 12

In a cathode ray beam storage tube system as recited in claim 8 wherein there is included a source of unblanking pulses for unblanking the cathode ray beam of said storage tube, and said pulse generator means includes means for generating said control current as a function of the unblanking pulse interval and frequency.

Claim 13

A cathode ray tube control system for controlling the beam current of a cathode ray tube as a function of first and second signals, said system comprising: means for producing a series of pulses whose duty factor is a function of said first signal; means for amplitude modulating said series of pulses as a function of said second signal; and means for applying said amplitude modulated series of pulses to said cathode ray tube so that its beam current is controlled in response thereto.

Claim 14

A cathode ray tube control system for controlling the beam current of a cathode ray tube as a function of first and second signals, said system comprising: means for producing a series of pulses whose duty factor is a function of said first signal; means for amplitude modulating said series of pulses as a function of said second signal; and means for applying said amplitude modulated series of pulses to said cathode ray tube so that its beam current is controlled in response thereto.