| 摘要 |
The system uses ultrasound combined with sound effects to simulate presence of predator. The procedure includes the transmission of an ultrasonic acoustic signal with a frequency between 20 and 50 kHz. This comprises successive trains (T) of at least two pulses (I1, I2, I3), each of duration between several milliseconds and several hundreds of milliseconds. The pulse trains are separated by a time interval of between 5 and 60 seconds. This signal reproduces the distress call emitted by rats and other rodents in response to the scent of their predator, such as a fox. On top of the ultrasound signal a further sound signal may be superimposed, simulating the presence of the predator.
|
