| 摘要 |
<p>A speed detecting device which has a detector (101) for generating 2-phase sinusoidal signals (PA, PB) having frequencies which are proportional to the rotating speeds of motors, said signals also having phase displacement of π/2 to produce, with the sinusoidal signals (PA, PB), voltages (VL, VH) which will vary with the rotation speeds of the motor thereby detecting the speeds. This speed detecting device has a quadruple circuit (107) and a frequency-to-voltage converter (107), and further a first speed generator for generating the voltage (VH) representing the actual speed in a high speed range, a 4-phase rectangular wave signal generating circuit (106), a differentiating circuit (109), and a synchronous rectifying circuit (110), a second speed generator for generating a voltage representing the actual speed (VL) in a low speed range, thereby generating the voltages (VH, VL) in response to the high or low speed rotation.</p> |
