| 摘要 |
<p>The invention sets forth a method of determining a filling level of a product contained in a tank using a radar level gauge system. The steps include generating a transmission signal using first pulse generating circuitry outputting a first signal having a first oscillation frequency having a first pulse repetition frequency. The invention uses a second pulse generating circuitry having a resonator element having an input and an output, a reference signal in the form of a second pulse train having a second pulse repetition frequency which differs from the first pulse repetition frequency by a predetermined frequency difference. The invention forms a measurement signal including a sequence of values representing a time correlation between a pulse of the reference signal and the reflected signal, and determines the filling level based on the measurement signal. The step of generating the reference signal includes providing the first signal to the input of the resonator element in the second pulse generating circuitry, monitoring an output signal from the resonator element, the output signal substantially corresponding to the first signal being delayed by a time delay, controlling at least one parameter of the second pulse generating circuitry to a parameter value resulting in the time delay corresponding to the predetermined frequency difference, and providing the output signal from the resonator element to the input of the resonator element while maintaining the parameter value of the at least one parameter, thereby generating the reference signal.</p> |
