| 摘要 |
A vehicle road speed signal source including a speed sensor and a frequency to voltage converter for generating a pulsed output signal having an average magnitude proportional to the road speed of an associated vehicle. The speed sensor has a high energy product magnet attached to the drive shaft of the vehicle which induces current pulses in approximately spaced pick-up coil. The pick-up coil is connected to a preamplifier having a low input impedance to reduce the effect of spurious signals such as ignition noise. The preamplifier output signal may be shaped into a square wave pulse train or may be applied directly to the frequency to voltage converter which generates a pulsed output signal having a duty cycle and therefore an average magnitude proportional to the vehicle road speed. |
