| 摘要 |
1488019 Position encoding XEROX CORP 15 Nov 1974 [20 Dec 1973] 49471/74 Heading G1A [Also in Division G4] In a cartesian co-ordinate position encoder, X and Y displacements cause shaft encoders to generate quadrature pairs of squarewave signals Al, B1 and A2, B2 which are taken into registers 6 and 12 at clock instants occurring at a frequency of at least 8 times that of the squarewaves, the registers providing an 8 bit address signal to a read-only memory 16 which outputs pulses on up or down lines to X and Y counters 20 as appropriate depending on the difference in the contents of the registers. The position encoders may be photoelectric encoders as described in Specification 1480269 [Division G1]. |
