The present disclosure relates to a method for operating a radar sensor, in particular a long range radar sensor, in a motor vehicle. The radar sensor has a detection range defined by an area in front of the motor vehicle or an area behind the motor vehicle. The radar sensor is operated with a transmitting power that determines the detection range of the radar sensor, and radar data of the radar sensor is evaluated within the radar sensor to detect objects in the detection range. The transmitting power of the radar sensor is increased from a first transmitting power value to a second transmitting power value when a switching criterion is met, indicating that no objects satisfying a relevance criterion have been detected by the radar sensor.

A radar monolithic microwave integrated circuit (MMIC) includes a first transmission channel configured to output a first continuous-wave transmit signal based on a local oscillator signal having a first frequency; a first phase shifter provided on the first transmission channel and configured to apply a first phase setting to the first continuous-wave transmit signal to generate a first transmit signal having the first frequency; a first transmit monitoring signal path configured to couple out a portion of the first transmit signal from the first transmission channel as a first transmit monitoring signal; a frequency multiplier configured to receive a test signal and convert it into a multiplied test signal having a second frequency, where the first and the second frequencies are separated by a frequency offset; and a down-conversion mixer configured to mix the multiplied test signal and the first transmit monitoring signal to generate a first mixer output signal.

A method is described below which can be used in a radar system. According to one example implementation, the method comprises providing a digital baseband signal using a radar receiver. The baseband signal comprises a plurality of segments, wherein each segment is assigned to a chirp of an emitted chirp sequence and each segment comprises a specific number of samples. For each signal sequence of n samples of the segments, where n in each case denotes a specific sample position within the respective segment, the method comprises the following: detecting interference-affected samples of the signal sequence; splitting the signal sequence into two or more sub-band signal sequences, wherein each sub-band signal sequence is assigned in each case to a frequency sub-band; replacing interference-affected samples in the two or more sub-band signal sequences in each case with a value which is based on adjacent samples in order to obtain corrected sub-band signal sequences; and determining a corrected signal sequence of n samples of the segments based on the corrected sub-band signal sequences.

The transmitter includes a phase shifter that shifts a phase of an input signal and outputs a shifted signal; a first control circuit changes a phase shift amount of the phase shifter; a phase difference signal output circuit outputs a phase difference signal between the shifted signal and the reference signal; an extreme value output circuit outputs a value of the phase difference signal when the phase difference signal becomes the extreme value; a target value output circuit outputs a target value based on an output from the extreme value output circuit; and a second control circuit controls the phase shift amount of the phase shifter such that a value of the phase difference signal coincides with the target value. The phase shifter outputs, as a transmission wave, the input signal the phase of which is shifted by the phase shift amount controlled by the second control circuit.

A method for detecting the environment of a motor vehicle utilizing a radar system includes bringing about frequency modulation utilizing an oscillator and generating a sequence of transmission-frequency-modulated transmit signals, which each having the same nominal frequency profile, apart from a variation in frequency position. Received signals for object detection are evaluated. A one time-discrete signal per transmit signal is used which includes information about the frequency profile of the transmit signal and which is generated by sampling of an analog signal or by reading out of a free-running counter at predetermined points in time. These time-discrete signals are unnormalized by way of the transmit signals with regard to the position of their phase and/or their initial value.

A method for calibrating a radar system includes generating an RF oscillator signal and distributing the RF oscillator signal to a plurality of phase shifters each providing a respective phase-shifted RF oscillator signal; receiving the phase-shifted RF oscillator signals by corresponding radar chips and radiating the phase-shifted RF oscillator signal via a first RF output channel of a first one of the radar chips; receiving a back-scattered signal by at least one RF input channel of each radar chip and generating a plurality of base-band signals by down-converting the received signals into a base band using the phase-shifted RF oscillator signals received by the corresponding radar chips; determining a phase for each base-band signal; and adjusting the phase shifts caused by the phase shifters such that the phases of the base-band signals match a predefined phase-over-antenna-position characteristic.

A radar system includes a transmitter including a power amplifier (PA) for amplifying a local oscillator (LO) signal, to generate an amplified signal. The radar system also includes a receiver including an IQ generator for generating an I signal based on the LO signal and for generating a Q signal based on the LO signal and a low noise amplifier (LNA) for amplifying a looped back signal, to generate a receiver signal. The receiver also includes a first mixer for mixing the receiver signal and the I signal, to generate a baseband I signal and a second mixer for mixing the receiver signal and the Q signal, to generate a baseband Q signal. Additionally, the radar system includes a waveguide loopback for guiding the amplified signal from the transmitter to the receiver as the looped back signal.

A method carried out using a radar level gauge system, the tank having a tank roof supporting the radar level gauge system, a tank wall, and a tank atmosphere in a space defined by a surface of a product in the tank, the tank roof, and the tank wall, wherein the method comprises generating and transmitting an electromagnetic first transmit signal; propagating the first transmit signal through the tank atmosphere towards a corner reflector formed by the surface of the product and the tank wall where the surface of the product meets the tank wall, the corner reflector being at a known horizontal distance from the radar level gauge system; receiving an electromagnetic first reflection signal resulting from reflection of the first transmit signal at the corner reflector; and performing a filling level determination and/or a verification operation for the radar level gauge system based on a timing relation between the first transmit signal and the first reflection signal, and the known horizontal distance between the radar level gauge system and the corner reflector.

A method of measuring phase noise (PN). A PLL frequency synthesizer is provided including a first phase frequency detector (PFD) receiving a reference frequency signal coupled to a first charge pump (CP) coupled to a VCO having an output fedback to the first PFD through a feedback divider that provides a divided frequency signal to the first PFD which outputs an error signal, and PN measurement circuitry including a replica CP coupled to an output of a second PFD or the first PFD. The error signal is received at the replica CP or the divided and reference frequency signal are received at the second PFD, wherein the replica CP outputs a scaled phase error current which is current-to-voltage converted and amplified to provide an amplified phase error voltage, and digitized to provide a digital phase error signal. The digital phase error signal is frequency analyzed to generate a PN measurement.

A system includes a local oscillator (LO) signal generation circuit, a receiver (RX) circuit, and a calibration circuit. The LO signal generation circuit generates an LO signal according to a reference clock, and includes an active oscillator that generates the reference clock. The active oscillator includes at least one active component. The RX circuit generates a processed RX signal by processing an RX input signal according to the LO signal. The calibration circuit checks a signal characteristic of the processed RX signal by detecting if a calibration tone exists within a receiver bandwidth, set a frequency calibration control output in response to the calibration tone being not found in the receiver bandwidth, and output the frequency calibration control output to the LO signal generation circuit. The LO signal generation circuit adjusts an LO frequency of the LO signal in response to the frequency calibration control output.