Browse Prior Art Database

Dash Line Generator

IP.com Disclosure Number: IPCOM000095105D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Thorpe, RA: AUTHOR

Abstract

In image processing systems certain applications such as displaying engineering drawings necessitate a need for generation of dash line vectors for use in a CRT display. A circuit adapted to provide a dash line capability for producing uniformly sized dashes in a constant time, variable velocity CRT display system irrespective of the length of the vector operates as follows.

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Dash Line Generator

In image processing systems certain applications such as displaying engineering drawings necessitate a need for generation of dash line vectors for use in a CRT display. A circuit adapted to provide a dash line capability for producing uniformly sized dashes in a constant time, variable velocity CRT display system irrespective of the length of the vector operates as follows.

Initially, the blank-unblank signal on line 1 1 is blanked.

The resulting positive output from Inverter 12 maintains electronic switch 13 closed. Thus, the output of the integrator RC comprising resistor 17 and capacitor 19 is shorted to ground. Voltage Ve proportional to the vector length is applied via conductor 21 to function generator 23 to generate a signal K/Ve inversely proportional to the vector length, which is applied to comparator 25.

At the same time, the blank-unblank signal on line 11 is unblanked for the entire vector generation period. Switch 13 is opened causing RC to charge toward reference voltage level E applied to terminal 28.

Voltage E is much larger than K/Ve to provide a linear output from RC as it charges toward K/V. When the RC output equals K/Ve, the comparator 25 produces an output. This, when logically combined with the unblank signal in And 27, closes switch 13 and discharges RC to ground.

The signal from And 27 is inverted through Inverter 31 to provide a control signal on line 32 which is applied to And 35. A mode status indication of dash, ...