Electric lamp and discharge devices: systems – Cathode ray tube circuits – Cathode-ray deflections circuits
Patent
1984-05-29
1986-07-01
Blum, Theodore M.
Electric lamp and discharge devices: systems
Cathode ray tube circuits
Cathode-ray deflections circuits
315382, 315367, 358158, 331 57, 307271, H01J 2956
Patent
active
045982341
ABSTRACT:
A digital electron optics correction circuit for correcting the focus and astigmatism in a displayed image on a CRT is disclosed. The circuit includes a clock generator for generating a selected number of pulses between each horizontal blanking synchronization pulse. These clock pulses are then counted by an X-address counter and a first address signal is generated corresponding to a particular horizontal position on the CRT screen for each count of the X-address counter. A pulse generator circuit is also provided which is coupled to receive the vertical blanking synchronization pulses and which provides a selected number of output pulses for each vertical blanking synchronization pulse. A Y-address counter counts the output pulses from the pulse generator circuit and provides a second address signal corresponding to a particular vertical position on the CRT screen for each count. These X- and Y-addresses are then input to focus and astigmatism ROMS which are preprogrammed with an appropriate control correction signal for each X-Y-address. In a first embodiment of the invention, the pulse generator circuit inclues a dividing circuit which is coupled to receive the horizontal blanking synchronization pulses. The dividing circuit then provides an output pulse for every N2 pulses received, and each such output pulse is then utilized to increment the Y-address counter. In a second embodiment, the pulse generator circuit includes a second clock generator for generating N3 pulses between successive vertical blanking synchronization pulses, with each clock pulse being used to increment the Y-address counter. Also disclosed in a specialized clock generator cirucit for generating a preselected number of pulses between successive gating pulses.
REFERENCES:
patent: 3852640 (1974-12-01), McCarthy
patent: 3982193 (1976-09-01), Maringer
patent: 4099092 (1978-07-01), Bristow
patent: 4189784 (1980-02-01), Mendenhall
patent: 4203051 (1980-05-01), Hallett et al.
patent: 4388619 (1983-06-01), Beck
Blum Theodore M.
Cain David
Hulse Robert S.
Smith-Hill John
Tektronix Inc.
LandOfFree
Digital image correction circuit for cathode ray tube displays does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital image correction circuit for cathode ray tube displays, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital image correction circuit for cathode ray tube displays will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1084040