Abstract: An apparatus for ascertaining and monitoring a fill level and includes a transmitting/receiving unit and a delay circuit. The delay circuit includes at least a sampling clocking oscillator, which produces a sampling signal having a sampling frequency, a transmission clocking oscillator, which produces a pulse repetition signal having a pulse repetition frequency, and a frequency converter, which produces by means of sequential sampling a difference signal. The apparatus further includes a control/evaluation unit, which determines on the basis of travel time the fill level. Provided on the control/evaluation unit is an external clocking input, which is connected via a clocking line with a first clocking output of the sampling clocking oscillator or with a second clocking output of the transmission clocking oscillator. A stabilized and cost-favorable control circuit for producing an intermediate frequency signal with a highly accurately determinable, transformation factor results.

Abstract: An apparatus for ascertaining and monitoring a fill level and includes a transmitting/receiving unit and a delay circuit. The delay circuit includes at least a sampling clocking oscillator, which produces a sampling signal having a sampling frequency, a transmission clocking oscillator, which produces a pulse repetition signal having a pulse repetition frequency and a frequency converter, which produces by means of sequential sampling a difference signal. The apparatus further includes a control/evaluation unit, which determines on the basis of travel time the fill level. Provided on the control/evaluation unit is an external clocking input, which is connected via a clocking line with a first clocking output of the sampling clocking oscillator or with a second clocking output of the transmission clocking oscillator. A stabilized and cost-favorable control circuit for producing an intermediate frequency signal with a highly accurately determinable, transformation factor results.

Abstract: A method for determining the fill level (l) on the basis of the travel time (t) of a high-frequency measuring signal (SHF), which is transformed into a lower frequency, intermediate-frequency measuring signal (SZF), wherein the transformation factor (KT) is obtained from a difference frequency (fSweep) between a pulse repetition frequency (fPRF) and a sampling frequency (fsample) The pulse repetition frequency (fPRF) or the sampling frequency (fsample) is altered on the basis of a control with a control variable (c_var) through an appropriate control algorithm, such that a desired value (fSweep—setpoint) of the difference frequency is controlled to; wherein a gradient (grad) of at least two values is determined, and on the basis of the gradient (grad) and the difference frequency (fSweep), or difference time (tSweep), in the case of a set control variable (c_var), an operating point (OP) of the control is determined, and the control algorithm is adjusted accordingly thereto.

Abstract: A method for determining the fill level (l) on the basis of the travel time (t) of a high-frequency measuring signal (SHF), which is transformed into a lower frequency, intermediate-frequency measuring signal (SZF), wherein the transformation factor (KT) is obtained from a difference frequency (fSweep) between a pulse repetition frequency (fPRF) and a sampling frequency (fsample) The pulse repetition frequency (fPRF) or the sampling frequency (fsample) is altered on the basis of a control with a control variable (c_var) through an appropriate control algorithm, such that a desired value (fSweepsetpoint) of the difference frequency is controlled to; wherein a gradient (grad) of at least two values is determined, and on the basis of the gradient (grad) and the difference frequency (fSweep), or difference time (tSweep), in the case of a set control variable (c_var), an operating point (OP) of the control is determined, and the control algorithm is adjusted accordingly thereto.