Fill level measurement device

Patent metadata

Field	Value
Publication number	US-10267666-B2
Application number	US-201515543815-A
Country	US
Kind code	B2
Filing date	Dec 14, 2015
Priority date	Jan 15, 2015
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

The present disclosure relates to a measuring device for measuring a fill level of a material in a container based on time of flight principles, including components that serve to generate, transmit and receive a measurement signal and further serve to convert said measurement signal into an analog intermediate frequency signal having an expected signal frequency within a predetermined frequency range, said intermediate frequency signal including information corresponding to the fill level of the material in the container, wherein an analog to digital converter is provided that serves to subsequently sample the intermediate frequency signal, said analog to digital converter employing a sampling frequency less than the expected signal frequency of intermediate frequency signal.

First claim

The invention claimed is:

1. A measuring device based on the time of flight principle, comprising:
components embodied to generate, to transmit and to receive a measurement signal corresponding to a fill level of a material in a container and further embodied to convert the measurement signal into an analog intermediate frequency signal having an expected signal frequency within a predetermined frequency range, the analog intermediate frequency signal including measurement information from the measurement signal; and
an analog to digital converter configured to sample the analog intermediate frequency signal and to output a digital intermediate frequency signal, wherein the analog to digital converter is further configured to sample at a sampling frequency less than the expected signal frequency of the analog intermediate frequency signal,
wherein when the frequency of the analog intermediate frequency signal corresponds to said expected frequency, the analog to digital converter outputs a digital intermediate frequency signal with a frequency that is shifted down with respect to the frequency of the analog intermediate frequency signal, and wherein a magnitude of the frequency shift corresponds essentially to the sampling frequency of the analog to digital converter.

2. The measuring device of claim 1 , further comprising:
a microprocessor, wherein the analog to digital converter is integrated in the microprocessor.

3. The measuring device of claim 2 , wherein the microprocessor includes a component group configured to perform a decimation process on the digital intermediate frequency signal.

4. The measuring device of claim 2 , wherein the microprocessor includes a component group configured to square, to low-pass filter, and to perform a square root on the digital intermediate frequency signal.

5. The measuring device of claim 2 , wherein the microprocessor includes a component group configured to forward-backward filter the digital intermediate frequency signal.

6. The measuring device of claim 1 , further comprising a band-pass filter configured to pass the predetermined frequency range and to filter frequencies greater than a measurement signal frequency of the measurement signal.

7. The measuring device of claim 6 , wherein the band-pass filter is configured to pass a frequency range corresponding to the predetermined frequency range, and wherein the passed frequency range is smaller than half the sampling frequency of the analog to digital converter.

8. The measuring device of claim 6 , further comprising a variable amplifier connected between the band-pass filter and the analog to digital converter.

9. The measuring device of claim 8 , further comprising a second band-pass filter connected between the variable amplifier and the analog to digital converter.

10. The measuring device of claim 9 , wherein the analog to digital converter is connected directly to the second band-pass filter.

11. The measuring device of claim 1 , further comprising:
a local oscillator configured to generate a local oscillator signal in the measuring device; and
a mixer configured to mix the received measurement signal with the local oscillator signal and to output the analog intermediate frequency signal, wherein the measuring device is a pulsed radar based device and wherein the received measurement signal includes a sequence of electromagnetic pulses.

Assignees

• Endress Hauser Gmbh Co Kg
• Endress Hauser Se Co Kg

Inventors

• Seiler Christian
• Deuber Patrick

Classifications

• G01S13/88

  Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) · CPC title

• G01F23/284 Primary

  Electromagnetic waves · CPC title

• G01S7/285 Primary

  Receivers · CPC title

• G04F5/04

  using oscillators with electromechanical resonators {producing electric oscillations or timing pulses} · CPC title

• G01S13/10

  using transmission of interrupted, pulse modulated waves (determination of distance by phase measurement G01S13/32) · CPC title