| 摘要 |
<p>1478633 Keyboards with coded outputs OMRON TATEISI ELECTRONICS CO 11 July 1974 [18 July 1973] 30755/74 Heading G4H Information input apparatus (e.g. for a calculator or a cash register) comprises means TM for producing first relatively long timing signals T1-T6 and feeding them sequentially to different gating circuits NA1-NA6, means for producing second relatively short timing signals t4 (one during each of T1-T6) and feeding them simultaneously to NA1-NA6; and a plurality of information input switches K1-K15 each associated with at least one of the gating circuits, each circuit in combination with its associated switch or switches producing a logic output signal b1-b6 indicating whether or not an associated switch is actuated during the periods when the circuit receives the first and second signals. It is stated that the use of signal t4 results in reduced power dissipation caused by circuit operation, and is an improvement over the keyboard disclosed in Specification 1,415,469 (Figs. 1-4, not shown). In the embodiments of Fig. 5 and Fig. 8 (not shown), each key is associated with two gating circuits; in the embodiment of Fig 10 (not shown) it is associated with one circuit. In the embodiment shown, when no key is depressed NAND gate NG produces a "1" level signal; depression of, e.g., K1 connects lines R1 and R2 to produce extra pulses on these lines (dotted-line pulses in b1 and b2), giving rise to signal K1 from NG. The presence of signals t4 (each of which occurs for only a small part of the period of timing signals T) ensures that the subsequent circuitry is actuated for a shorter time than if these pulses were absent (since the output of NG would then depend on the period of signals T). The pulse signal K is fed via a holding circuit HLD to a MOSFET decoder matrix DC, Fig. 6A (not shown) which outputs a signal on one of fifteen lines to indicate the depressed key.</p> |
