| 摘要 |
A radar level gauging principle including transmitting at least two time separated carrier wave pulses having equal carrier frequencies, determining a change in phase shift associated with two pulses in the transmit signals having equal frequencies, comparing the change with a threshold value, and depending on a result of the comparing step, determining the distance based on a relationship between the transmit signals and the return signals. By comparing the actual phase resulting from two substantially identical pulses transmitted a certain time apart, an indication of a change of filling level can be obtained. This indication can then be used to initiate a full measurement cycle. |
