Differential error convergence correction
AssigneeThomson Consumer Electronics, Inc.
InventorJohn B. George
Life of this patent
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Abstract
A convergence correction circuit, for a cathode ray tube projecting images having keystone, differential sine and differential left edge curl distortions, comprises generators for horizontal rate sine, horizontal rate sawtooth and horizontal rate pulse waveforms. A summer combines the horizontal rate waveforms into a horizontal rate composite waveform. A multiplier and an amplifier generate as an output signal a product of the horizontal rate composite waveform and a vertical rate sawtooth waveform. A convergence correction coil is coupled for receiving the output signal and generating a dynamic magnetic field correcting the keystone, differential sine and differential left edge curl distortions.
Claims24
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- means for summing three horizontal rate waveforms to define a horizontal rate composite waveform;
- means for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform, said horizontal rate composite waveform;
- means for amplifying said output signal;
- and,
- a correction coil for said cathode ray tube coupled for receiving said amplified output signal and generating a dynamic magnetic field responsive to said output signal, said output signal having a first component for correcting a keystone distortion, a second component for correcting a red/blue sinusoidal distortion and a third component for correcting a red/blue left edge curl distortion.
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- a horizontal rate generally sinusoidal waveform generator;
- a horizontal rate sawtooth waveform generator;
- a horizontal rate pulse waveform generator;
- means for summing horizontal rate generally sinusoidal, sawtooth and pulse waveforms supplied by said waveform generators to define a horizontal rate composite waveform;
- a waveform multiplier for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform;
- an amplifier for said output signal;
- and,
- a correction coil for said cathode ray tube coupled for receiving said amplified output signal and generating a dynamic magnetic field responsive to said amplified output signal for correcting said distortion.
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- a source of first and second horizontal rate waveforms, said first waveform being a horizontal rate generally sinusoidal waveform;
- means for summing said first and second horizontal rate waveforms supplied by said source to define a horizontal rate composite waveform;
- a waveform multiplier for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform, said horizontal rate composite signal being DC coupled to said waveform multiplier;
- an amplifier for said output signal;
- and,
- a correction coil for said cathode ray tube coupled for receiving said amplified output signal and generating a dynamic magnetic field responsive to said output signal for correcting said distortion.
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- means for generating a horizontal rate sawtooth waveform;
- means for generating a horizontal rate generally sinusoidal waveform;
- means for summing said horizontal rate sawtooth and generally sinusoidal waveforms to define a horizontal rate composite waveform;
- means for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform;
- and,
- a correction coil for said cathode ray tube coupled for receiving said output signal and generating a dynamic magnetic field responsive to said output signal for correcting said distortion.
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- means for generating a horizontal rate sawtooth waveform;
- means for generating a horizontal rate pulse waveform;
- means for generating a horizontal rate generally sinusoidal waveform
- means for summing said horizontal rate sawtooth, pulse and generally sinusoidal waveforms to define a horizontal rate composite waveform;
- means for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform, said horizontal rate composite waveform being DC coupled to said product generating means;
- means for amplifying said output signal;
- and,
- a correction coil for said cathode ray tube coupled for receiving said amplified output signal and generating a dynamic magnetic field responsive to said output signal, said output signal having a first component for correcting a keystone distortion, a second component for correcting a red/blue left edge curl distortion and a third component for correcting a red/blue sinusoidal distortion.
A correction circuit for a cathode ray tube displaying images subject to distortion, said circuit comprising:
- means for summing three horizontal rate waveforms to define a horizontal rate composite waveform;
- means for generating as an output signal a product of said horizontal rate composite waveform and a vertical rate waveform, said horizontal rate composite waveform;
- means for amplifying said output signal;
- and,
- a correction coil for said cathode ray tube coupled for receiving said amplified output signal and generating a dynamic magnetic field responsive to said output signal, said output signal having a first component for correcting a keystone distortion, a second component for correcting a red/blue generally sinusoidal distortion and a third component for correcting a red/blue edge curl distortion.
Dependencies are inferred from the claim text.