METHOD AND DEVICE FOR MEASURING THE DAMPING OF A LC-OSCILLATING CIRCUIT

摘要

Known oscillators having two wire-wound coils without pick-up (fig. 1) are difficult to control and not suitable for CMOS technology. According to the invention such an oscillator first receives an additional current mirror. By addition of said current mirror (Q3, Q4) and other power sources an oscillator is obtained which is easier to control and suitable for use in CMOS technology. By exciting the oscillating circuit by means of switched power sources Io, amplitude is rendered proportional to Rp and Io. For the purpose of simplification only simple MOS transistors are shown in the drawings. In practice, more complicated structures are used as switches and power sources. In this way amplitude can be better controlled independently of oscillating circuit damping. The above method is used in distance measurement. Additional control of amplitude is used to correct manufacturing tolerances and temperature sensitivity.