| 摘要 |
<p>1493988 Measuring angle of rotation, digitally SIEMENS AG 18 Feb 1975 [18 Feb 1974] 6764/75 Heading G1N [Also in Division H3] The angular position # of a radar antenna A continuously rotated at fa revolutions per second is digitized by amplitude modulating a fundamental frequency fo by sin # and cos # to give two signals Ul = cos[2#(fo + fa).t] 2#(fo - fa).t] and U2 = sin[2#(fo + fa).t] + sin[2#(fo - fa).t], either one of which is phase-shifted 90 degrees and added to the other to form a third signal U3 having only one frequency component (fo + fa) or (fo - fa) which is applied to the clock input 3 of a D-type flip-flop whose preparation input D receives references pulses Ud of frequency n.fo (n an integral power of 2, e.g. 128) and whose Q output delivers a pulse train Z 1 of frequency n.fa, each pulse representing an angular increment As shown, fa = 1, fo = 400 Hz. The reference pulses Ud are synchronized to fo by a phase-lock loop-alternatively, a frequency multiplier could be used. The pulse train Z 1 is fed to a shift register WZ. Rl, R4 adjust the relative amplitude and phase of U1, U2. C2 by-passes interference.</p> |
