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Character Speed Up

IP.com Disclosure Number: IPCOM000094229D
Original Publication Date: 1966-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Carlock, FR: AUTHOR [+3]

Abstract

In display environments employing cathode ray display tubes with electromagnetic deflection circuits, the deflection circuits are the limiting factor insofar as time is concerned. The digital data used to generate the display can be handled at rates far in excess to those required to effect the actual beam deflection. A speed-up in deflection rates can be achieved by momentarily overdriving the deflection circuits.

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Character Speed Up

In display environments employing cathode ray display tubes with electromagnetic deflection circuits, the deflection circuits are the limiting factor insofar as time is concerned. The digital data used to generate the display can be handled at rates far in excess to those required to effect the actual beam deflection. A speed-up in deflection rates can be achieved by momentarily overdriving the deflection circuits.

This overdrive or speed-up circuit permits a substantial increase in the deflection rates of a push-pull step current deflection system. Only one unit of deflection current control is shown since the additional units are similar. Latch 11 is under control of a double transmission line L1 and L2 and assumes one state or the other depending on the signals applied. The 1 output of latch 11 is connected to the X winding by RC circuit 12 and buffer amplifier 14. The 0 output of latch 11 is connected to the X winding by RC circuit 15 and buffer amplifier 16.

If latch 11 is switched to 1 from 0, one unit of current is switched out of the X winding. This is because the 0 output of latch 11 becomes open. Simultaneously, one unit of current is added to X winding since the 1 output of latch 11 is grounded. Circuit 12 in the current path of the X winding provides the on speed-up or overdrive since the voltage across the capacitor cannot change instantaneously and appears as a short. As the current charges the capacitor, the quiescent desired state is reached. The circuit, thus far described, does not however provide a speed up in the off direction for winding X since...