| 摘要 |
PCT No. PCT/JP82/00136 Sec. 371 Date Dec. 13, 1982 Sec. 102(e) Date Dec. 13, 1982 PCT Filed Apr. 23, 1982 PCT Pub. No. WO82/03692 PCT Pub. Date Oct. 28, 1982.A speed detecting apparatus having a detector (101) for generating two sine-wave signals (PA, PB) which are pi /2 out of phase with each other and have a frequency proportional to the speed of rotation of a motor so that actual-speed voltages (VL, VH) can be produced which are proportional to the speed of rotation of the motor. The speed detecting apparatus includes a quadrupling circuit and a frequency-to-voltage converter 107. Also included is a first speed generator for generating the actual-speed voltage (VH) in a high-speed range and a second speed generator which includes a four-phase rectangular signal generating circuit (106), a differentiating circuit (109), and a synchronous rectifier circuit (110) for producing the actual-speed voltage (VL) in a low-speed range. The voltages generated by the first and second speed generators are selectively issued as an output depending on whether the motor rotates at a high speed or a low speed. |
