Animal deterrent ultrasound generator - has swept pseudo-random frequency generator using shift register control

摘要

The device has control of the frequency of the oscillator by using a shift register circuit whose last stage is coupled back to the first via a coincidence gate. Further inputs to the gate are taken from other stages in the register. The output power is high and is derived from a variable frequency, e.g. between 18kHz and 40kHz, variable output local oscillator. This supplies a power amplifier and one or more output transducers. The generator overcomes the fall in efficiency in keeping animals away, due to their becoming familiar with constant frequencies or regularly swept frequency ranges, by varying the sweep rate and changing the frequency in a pseudo-random fashion.