Level of substance in a container can be determined by exciting vapor in unfilled space within the container. Variable frequency oscillator and emitting transducer can provide signals to excite resonance of vapor. Sensors can measure the peak resonant signal of vapor excited in unfilled space within the container as the amount of substance in the container changes. A signal-processing unit coupled to the sensor and variable frequency oscillator can process signals sensed by the sensing transducer and can extract them from background noise affecting the acoustic signal of the system using correlation functions by referencing the signal generated by the variable frequency oscillator. A computer can obtain the sign processed by the signal-processing unit and calculate the unfilled space within the container and derive therefrom an amount of filled space representing the amount of the substance contained therein. A gauge can indicate the amount of substance in the container.

A method for sensing at least one level parameter of at least one liquid in a tank. At least one bulk acoustic wave (BAW) sensor is positioned inside the tank. Electrodes of the BAW sensor are at least switchably connected to a positive feedback loop across an amplifier to provide an electronic oscillator. At least one acoustic viscosity measurement is determined from an output of the electronic oscillator, wherein the output of the electronic oscillator is different when the BAW sensor contacts the liquid as compared to when the BAW sensor contacts air. The level parameter is determined from the acoustic viscosity measurement.

A wound fluid collection system includes a canister adapted to collect bodily fluids from a tissue site. The canister includes an acoustic transducer adapted and positioned to insonify a cavity within the canister, the cavity being defined by a wall of the canister and the bodily fluids collected within the canister. A resonant frequency may be calculated based on a resulting received signal from the insonification. The resonant frequency may indicate a volume of the cavity within the canister. The difference between a known volume of the canister and the calculated volume of the cavity provides the volume of bodily fluid collected in the canister.

Electro acoustic volume measurement of a gas in a housing space may be performed using a hollow tube having a first end and a second end. A speaker is arranged to emit audio signals through the hollow tube. A first microphone of at least two microphones is located at the first end of the hollow tube, while a second microphone is located a defined distance from the first microphone within the hollow tube. A voltage-controlled oscillator controls the frequency of the audio signals to a resonance frequency where signals of the first microphone and the second microphone are 90 degrees out of phase while the first end of the hollow tube is located within the housing. The resonance frequency indicates a volume of the gas. The resonance frequency may be temperature-adjusted, or the volume may be temperature-adjusted.

A radar fill level measurement device for determining a fill level of a medium is provided, including a radar module to generate a transmission signal of at least 60 GHz; and an antenna coupled to the module and to transmit the signal to a surface of the medium and to receive a reflected signal, the module including a phase-locked loop including an oscillator, a phase detector, and a frequency divider, coupled between the oscillator output and the phase detector input, and a duplexer coupled between the oscillator and the antenna, the oscillator output being directly wired to an input of the duplexer, the frequency divider and the duplexer being coupled to a same oscillator output, the phase detector including a reference input and a phase detector output that is coupled to a control input of the oscillator. A method for operating a radar fill level measurement device is also provided.

A wound fluid collection system includes a canister adapted to collect bodily fluids from a tissue site. The canister includes an acoustic transducer adapted and positioned to insonify a cavity within the canister, the cavity being defined by a wall of the canister and the bodily fluids collected within the canister. A resonant frequency may be calculated based on a resulting received signal from the insonification. The resonant frequency may indicate a volume of the cavity within the canister. The difference between a known volume of the canister and the calculated volume of the cavity provides the volume of bodily fluid collected in the canister.

A device for measuring a mass of a body, the device including a support suitable for supporting the body, a frame and an actuator designed to vibrate the support relative to the frame. The device includes an accelerometer designed to measure values of an acceleration of the support upon vibration of the support, and an electronic control module designed to estimate the mass of the support body from the measured acceleration values.

A method for monitoring the condition of a coil, wherein the coil is part of a device for determining at least one process variable of a medium in a container, includes applying an electrical excitation signal to the coil and receiving an electrical reception signal from the coil, determining a first value for the reception signal at a first predefinable measurement time, comparing the first value for the reception signal at the first measurement time with a reference value, and determining a condition indicator for the coil on the basis of the comparison. Disclosed also is a device that is designed for carrying out the disclosed method.

A method for calibration or adjustment of any oscillatable unit with a mathematical model describing the oscillatable unit, wherein the oscillatable unit interacts with a medium located in a container, comprising the steps as follows: exciting the oscillatable unit via a real input signal to execute oscillations; the real output signal of the oscillatable unit is ascertained; the real output signal is digitized and a real output sequence is produced; the real input signal is digitized and a digital input sequence is produced; the digital input sequence is fed to a function block, which provides the mathematical model of the oscillatable unit in interaction with the medium. The mathematical model is defined by at least two sensor-specific variables; a virtual output sequence is produced via the mathematical model. The virtual output sequence is compared with the real output sequence; in the case of a deviation, the sensor-specific variables of the mathematical model are adaptively changed, until the deviation between the virtual output sequence and the real output sequence of the oscillatable unit lies within a predetermined tolerance range.

Acoustic volume indicators for determining liquid or gas volume within a container comprise a contactor to vibrate a container wall, a detector to receive vibration data from the container wall, a processor to convert vibration data to frequency information and compare the frequency information to characteristic container frequency vs. volume data to obtain the measured volume, and an indicator for displaying the measured volume. The processor may comprise a microprocessor disposed within a housing having lights that each represent a particular volume. The microprocessor is calibrated to provide an output signal to a light that indicates the container volume. The processor may comprise a computer and computer program that converts the data to frequency information, analyzes the frequency information to identify a peak frequency, compares the peak frequency to the characteristic frequency vs. volume data to determine the measured volume, and displays the measured volume on a video monitor.