East-west distortion correction
AssigneeKoninklijke Philips Electronics N.V.
InventorDonald G. Thompson
Life of this patent
Estimating the term…
Abstract
An apparatus for the correction of East-West distortion of images produced on the screen of a picture tube. More particularly, it concerns an electronic circuit for dynamically controlling the AC component of the drive signal to an East-West amplifier (14) in a picture tube horizontal scanning system. The electronic circuit comprises an input (44,66) for receiving a signal related to the beam current of the tube, an output for connection to the input of the East-West amplifier, a capacitive element (32,64), and an active control device (30,60) for controlling the capacitive element in response to the signal at the circuit input.
Claims21
An electronic circuit for controlling the AC component of the drive signal to an East-West amplifier in a picture tube horizontal scanning system, the circuit comprising;
- an input for receiving a signal related to the beam current of the picture tube, an output for connection to the input of the East-West amplifier, a capacitive means coupled to the output of the electronic circuit, and an active control device for controlling the capacitive means in response to the signal at the circuit input.
In an electronic circuit including an output for connection to an input of an East-West amplifier, a capacitive means, and an active control device, a method of supplying a drive signal to an East-West amplifier for a CRT horizontal scanning system, which comprises;
- deriving a signal determined by the beam current of the CRT,
- applying said signal to an input of the electronic circuit,
- coupling the capacitive means to the circuit output and to the active control device, and
- controlling the capacitive means via the active control device in response to a signal at the input of the electronic circuit, and in a manner to compensate an AC component of the drive signal.
An electronic circuit for control of the drive signal to an East-West amplifier in a picture tube horizontal scanning system, the circuit comprising:
- an input for receiving a signal dependent upon the beam current of the picture tube,
- an output for connection to an input of the East-West amplifier,
- a capacitive means,
- an active control device, and
- means for coupling the capacitive means and the active control device to one another and to the output of the electronic circuit, and wherein
- in response to the signal at the circuit input, the active control device provides a continuous and smooth control of the capacitive means so as to control an AC component of the drive signal at the circuit output in a manner that will reduce any pincushion distortion present in the picture tube.
Dependencies are inferred from the claim text.