| 摘要 |
A wireless keyboard and reader combination comprises a keyboard (10) having a plurality of keys (11), an antenna (24), and a plurality of passive transponder circuits (20), coupled to the antenna (24) and associated with the keys (11). The passive keyboard has enhanced range and preferably employs transponders employing backscatter transmission without using power from the reader interrogating field. For example, SAW transponders may be employed. Alternatively, the transponders (20) may be powered by energy from key activation. The transponder circuits (20) are coupled to the antenna and provide a coded response identifying a key in response to key activation. An associated reader includes a source of an interrogating field (16) applied to the antenna of the keyboard (10) and a decoder for determining the coded response from the passive transponder circuits. |
