| 摘要 |
<p>1530264 Indicating measurement HONEYWELL Ltd 26 Nov 1975 [27 Nov 1974] 51325/74 Heading G1J [Also in Divisions G4 and H3] A bar display system for indicating as a bar of light the magnitude of a quantity represented by an electrical input signal includes circuitry to produce scale marks as bright lines spaced along the bar of light. The system includes a bar display device 10 in the form of a flat bar-like gas-filled space having a transparent anode 11 on its inner front face and 200 equally spaced cathodes 12 on the back face, the cathodes being connected in three inter-digitated sets 13, 14, 15. A clock signal generator 20 drives a display drive circuit 21 for energizing each set of cathodes in sequence. A "keep-alive" anode 18 and cathode 17, and a reset cathode 16 are provided at one end of the space. A ramp signal generator 30 driven by the clock signal generator 20 supplies a ramp signal to a comparator 31 where it is compared with the input signal from 32. The comparator 31 feeds an anode drive circuit 33 which maintains the anode 11 energized while the ramp signal is less than the input signal, but de-energizes the anode when the ramp signal exceeds the input signal, to extinguish the visible discharge, and give a length of the bar of light proportional to the magnitude of the input signal. A divide-by-200 circuit 22, 23 sends a reset pulse to the ramp signal generator 30 and the display drive circuit 21 once per 200 pulses from the clock signal generator 20. The divide-by-200 circuit comprises a divide by-5 unit 22 and a divide-by-40 unit 23, the output of unit 22 also driving a one-shot circuit 24 controlling an output gate 25 of the clock 20. After every five pulses from the clock, there is thus a dwell before the pulses recommence, this dwell causing each 5th cathode 12 to be engergized for a longer time, and thus to be brighter than its neighbours.</p> |
