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Signal Generator for Character Generator

IP.com Disclosure Number: IPCOM000090934D
Original Publication Date: 1969-Aug-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Belser, KA: AUTHOR

Abstract

This electronic system, drawing 1, consists of digital and analog elements which produce analog X and Y deflection voltages. These can be used to trace any of several characters on an X-Y display or on a recording device. Blanking signals eliminate certain deflection operations during the drawing of a character. Digital data signal lines enable the specification of the character, its size, and its brightness. Digital control signal lines instruct the circuit when it is to sample the data and when it is to begin execution. The circuit responds with an execution-complete signal when production of the desired deflection waveforms is completed.

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Signal Generator for Character Generator

This electronic system, drawing 1, consists of digital and analog elements which produce analog X and Y deflection voltages. These can be used to trace any of several characters on an X-Y display or on a recording device. Blanking signals eliminate certain deflection operations during the drawing of a character. Digital data signal lines enable the specification of the character, its size, and its brightness. Digital control signal lines instruct the circuit when it is to sample the data and when it is to begin execution. The circuit responds with an execution- complete signal when production of the desired deflection waveforms is completed.

The character, character size, and character brightness are specified by loading registers 1...3. The system is also reset. Programmed clock 7 begins to run at its new rate. When an execute command is received, run latch 5 is set which, in turn, uninhibits integrators 15 and 16. This also opens gate 6 that meters whole clock pulses from clock 4 to counter 7. The first count causes the read-only memory 8 to gate data into register 9. This data specifies a stroke which is decoded during the second count interval with combinatorial logic 10. In the third count interval, memory address counter 1 is incremented by one. The stroke information is decoded by 10 is gated into registers 11 and 12. These, in turn, cause digital-to-analog converters DAC 13 and 14 to produce an output.

This output is integrated by integrators 15 and 16 to obtain linearly rising or falling deflection voltages until the next stroke begins. The output o...