Abstract: A radar level gauge having a wave guiding structure arranged to guide a measurement signal towards the surface and to return the reflected signal, and an electromagnetic wave transducer arranged to emit the measurement signal into the wave guiding structure as electromagnetic waves. The electromagnetic wave transducer has a plurality of radiating elements arranged in N?1 concentric feeder rings, where a radius of each feeder ring coincides with a radial zero of an electrical field of the H0N-mode, and feeding circuitry connected to feed the measurement signals from the transceiver circuitry to the radiating elements, thereby causing the electromagnetic wave transducer to excite electromagnetic waves in the H01-mode. With this choice of feeder ring radii, the H0N mode will not be excited.

Abstract: A radar level gauge having a wave guiding structure arranged to guide a measurement signal towards the surface and to return the reflected signal, and an electromagnetic wave transducer arranged to emit the measurement signal into the wave guiding structure as electromagnetic waves. The electromagnetic wave transducer has a plurality of radiating elements arranged in N?1 concentric feeder rings, where a radius of each feeder ring coincides with a radial zero of an electrical field of the H0N-mode, and feeding circuitry connected to feed the measurement signals from the transceiver circuitry to the radiating elements, thereby causing the electromagnetic wave transducer to excite electromagnetic waves in the H01-mode. With this choice of feeder ring radii, the H0N mode will not be excited.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal. The microwave signal source is configured to exhibit a phase noise greater than or equal to ?70 dBc/Hz @ 100 kHz offset from a carrier frequency for the transmit signal.

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal.

Abstract: The present invention relates to a radar level gauge system comprising PLL circuitry for generating an output signal. The PLL circuitry is configured to indicate a lock state of the PLL circuitry; and signal modifying circuitry is connected to the PLL circuitry for receiving the output signal and for modifying at least one property of the output signal for forming the transmit signal. The signal modifying circuitry is arranged and configured to receive a PLL status signal indicative of the lock state of the PLL circuitry, and to modify the at least one property of the output signal in response to the PLL status signal indicating that the PLL circuitry is in a locked state.

Abstract: A radar level gauge and a method for measurement of a distance to a surface of a product in a tank are disclosed. The radar level gauge comprises transceiver circuitry configured to transmit and receive electromagnetic signals, the transceiver circuitry comprises a frequency stabilizing feedback loop configured to generate the electromagnetic transmit signal in the form of a frequency sweep. The frequency stabilizing feedback loop is configured to generate an oscillation, forming a sinusoidal modulation of the frequency sweep. The radar level gauge further comprises a second mixer configured to mix an intermediate frequency signal and an integer multiple of the frequency of the sinusoidal modulation to provide an adjusted intermediate frequency signal, and processing circuitry configured to determine the distance based on the adjusted intermediate frequency signal. By providing a frequency sweep comprising a sinusoidal modulation, an improved sensitivity is achieved by the radar level gauge and method.

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal. The microwave signal source is configured to exhibit a phase noise greater than or equal to ?70 dBc/Hz @ 100 kHz offset from a carrier frequency for the transmit signal.

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal.

Abstract: A radar level gauge and a method for measurement of a distance to a surface of a product in a tank are disclosed. The radar level gauge comprises transceiver circuitry configured to transmit and receive electromagnetic signals, the transceiver circuitry comprises a frequency stabilizing feedback loop configured to generate the electromagnetic transmit signal in the form of a frequency sweep. The frequency stabilizing feedback loop is configured to generate an oscillation, forming a sinusoidal modulation of the frequency sweep. The radar level gauge further comprises a second mixer configured to mix an intermediate frequency signal and an integer multiple of the frequency of the sinusoidal modulation to provide an adjusted intermediate frequency signal, and processing circuitry configured to determine the distance based on the adjusted intermediate frequency signal. By providing a frequency sweep comprising a sinusoidal modulation, an improved sensitivity is achieved by the radar level gauge and method.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).

Abstract: The present invention relates to a radar level gauge system comprising PLL circuitry for generating an output signal. The PLL circuitry is configured to indicate a lock state of the PLL circuitry; and signal modifying circuitry is connected to the PLL circuitry for receiving the output signal and for modifying at least one property of the output signal for forming the transmit signal. The signal modifying circuitry is arranged and configured to receive a PLL status signal indicative of the lock state of the PLL circuitry, and to modify the at least one property of the output signal in response to the PLL status signal indicating that the PLL circuitry is in a locked state.

Abstract: Level gauging including an approximation of a distance to the surface of a product kept in a tank. The approximation is determined by relating an amplitude of a first harmonic of an IF signal with an amplitude of a second harmonic of the IF signal. Basically, each harmonics represents a given distance range. By determining the received power in two or more harmonics, and correlating them to each other, the distance may be estimated. Depending on modulation and other parameters the distance dependence may be very different, and may be selected to suit the application.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).

Abstract: Level gauging including an approxiamtion of a distance to the surface of a product kept in a tank. The approxiamtion is determined by relating an amplitude of a first harmonic of an IF signal with an amplitude of a second harmonic of the IF signal. Basically, each harmonics represents a given distance range. By determining the received power in two or more harmonics, and correlating them to each other, the distance may be estimated. Depending on modulation and other parameters the distance dependence may be very different, and may be selected to suit the application.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).

Abstract: A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising a transceiver including a signal generator for generating electromagnetic signals for transmission; a transmitter branch for transmitting the electromagnetic signals; and a receiver branch for receiving electromagnetic signals, the transmitter branch and the receiver branch each being connected to a transceiver input/output terminal.

Abstract: A radar level gauge system for determining a filling level of a product contained in a tank, comprising: a transceiver for generating, transmitting and receiving frequency-modulated electromagnetic signals; a transmitting propagating device electrically connected to the transceiver and arranged to propagate transmitted electromagnetic signals towards a surface of the product contained in the tank; and a receiving propagating device electrically connected to the transceiver and arranged to return echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals, including a surface echo signal resulting from reflection at the surface, back to the transceiver.

Abstract: A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising a transceiver including a signal generator for generating electromagnetic signals for transmission; a transmitter branch for transmitting the electromagnetic signals; and a receiver branch for receiving electromagnetic signals.

Abstract: A radar level gauge (RLG) system and method for determining a filling level of a filling material in a tank is disclosed. The RLG system comprises a transmitter for generating and transmitting an electromagnetic transmitter pulse signal, a transmitter controller for controlling means for pulse width adjustment for adjusting the pulse width of the transmitter pulse signal in dependence of at least one application specific condition. Further, the system comprises a signal medium interface connectable to means for directing said transmitter pulse signal towards said filling material and for receiving a reception pulse signal reflected back from said filling material; a receiver for receiving said reception pulse signal from the tank; and processing circuitry for determining the filling level of the tank based on said reflection pulse signal received by said receiver. The application specific condition(s) is e.g.