Thomas M Hay

US Patent:

44158912, Nov 15, 1983

Filed:

Mar 17, 1981

Appl. No.:

6/244599

Inventors:

Thomas M. Hay - Fort Lauderdale FL

Assignee:

Sony Corporation - Tokyo

International Classification:

G09G 306

US Classification:

340753

Abstract:

A programmable display device comprises a bar graph display panel having an anode, a series of spaced cathodes connected in groups representing respective phases and a reset cathode at one end of such series; and a scan control circuit for that display panel including a first programmable memory, such as, a PROM, having an output providing a clocking waveform representing a plurality of phase pulses and a reset pulse and being addressed to develop the phase pulses and reset pulse in a repeated cathode scanning cycle, a second programmable memory, desirably constituted by a plurality of PROMs and operated synchronously with the phase pulses for generating an analog ramp voltage of a slope and dynamic range determined by the second programmable memory, a comparator comparing the ramp voltage with a d. c. voltage characteristic of level of an audio or other signal to be displayed and providing a comparison output for energizing the anode in each cathode scanning cycle for an interval thereof in which such d. c. voltage exceeds the ramp voltage, and a circuit by which the phase pulses and reset pulse are applied to the series of cathodes in each cathode scanning cycle to provide a glow in the panel during energizing of the anode, with such glow occurring over a length of the panel representing the signal level to be displayed.