Pulse wave to parabola wave converter
AssigneeZenith Electronics Corporation
InventorStanley E. Lehnert
Life of this patent
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Abstract
An electronic image framing circuit is described for eliminating the visible effects of pincushion distortion at the edges of a television image. Toward this end, portions of video lines which extend beyond a selected straight line image boundary are blanked by a pulse processor. The pulse processor responds to conventional horizontal rate and vertical rate pulses for developing blanking pulses whose widths are varied at a vertical rate. The modified blanking pulses are applied to a conventional blanking circuit for blanking the portions of video lines which extend beyond the desired image area. A parabola generator is also described for use in developing the modified blanking pulses.
Claims3
A low insertion loss circuit for converting a pulse signal to a parabolic waveform, comprising:
- an input terminal for receiving the pulse signal;
- a first integrating resistance-capacitance network having a first input and output terminal said first input terminal coupled to said input terminal;
- a second integrating resistance-capacitance network having a second input and output terminal, said second input terminal coupled in series with said first output terminal;
- a third resistance-capacitance network having a third input and output terminal, said third input terminal coupled in series with said second output terminal for developing said parabolic waveform;
- and
- a diode coupled between said input terminal and said first output terminal assuming conductive and non-conductive states in response to opposite polarities of the pulse signal so as to alternately configure the circuit as a two-stage and a three-stage integrator, respectively.
Dependencies are inferred from the claim text.