| 摘要 |
<p>A generator vibrates low frequency sound vibrations and magnetic fields with superimposed high frequency noise which upsets the habits of rodents and most burrowing animals. The sounds are transmitted to the ground by the generator being connected to a pipe or shaft embedded in the ground, to buildings, structures or to water pipes which run underground. The circuitry permits random frequencies to be generated at random intervals by the use of cycling thermostats in circuit with the sound generator. The thermostats cycle due to the heat of the coils or resistors or from an electronic randomizing control circuit.</p> |
