An array antenna (10) that can form and sweep a predicted radiation beam pattern in different directions by using a subharmonic frequency signal from each voltage controlled oscillator (VCO) (20) to control the array phasing. Each VCO (20) generates a radio frequency carrier signal that drives an antenna element (16). A subharmonic signal is generated from a portion of the signal from the VCO (20). The subharmonic signal is mixed with a constant frequency signal to produce an intermediate frequency (IF) signal. The frequency of the IF signal is compared to the frequency of a variable frequency signal in a phase locked loop (PLL) (40). Since the phase of a signal is dependent on its frequency, the variable frequency signal is generated to have a frequency corresponding to a certain phase. The PLL (40) generates an error signal as a function of the difference in frequencies between these two signals. In response to the error signal, the VCO (20) changes the frequency of the carrier output signal. This process is continued by PLL (40) until the frequency of the IF signal is equal to the frequency of the variable frequency signal. The VCO (20) is now generating a signal having a frequency corresponding to the certain phase. The combined resultant relative phase excitation of all the antenna elements generates a maximum field intensity in a predicted direction.

A method in which a sensor system with a frequency-modulated signal source an a delay line for generating a time-delay reference signal is implemented. Phase errors are compensated by correcting the modulation (pre-equalization derived from the reference signal. Signals with a long running time are measured and additionally compensated by a computational, subsequent elimination (post-equalization). A high-pass filter is provided to that end.

FMCW doppler radar, in which a reference signal is generated from the transmit signal via a delay line and a mixer. A measuring signal which is received and mixed with the transmit signal is detected and digitized at the times of the zero crossings of the reference signal. In this way, the measuring signal can be evaluated at time intervals of equal phase of the reference signal. A downstream algorithm enables the generation of a strictly linearly frequency-modulated transmit signal. With this mechanism, phase errors of conventional radar systems are eliminated.

A method for the linearization of frequency modulated continuous wave (FMCW) radar devices having non-linear, ramp-shaped, modulated transmitter frequency progression x(t). With this invention, a correction phase term for compensation of the phase error in the reception signal q(t) is calculated on the receiver side in this device.

A distortion correction circuit having a mechanism for intercepting a distorted output signal from a receiver and for generating an Nth order signal. A circuit is provided to subtract the Nth order signal from the distorted output signal for providing a circuit output signal. Finally, a feedback loop is provided to feed back the circuit output signal for controlling the Nth order signal and for providing a distortion corrected circuit output signal. In a preferred embodiment, the distortion correction circuit includes a calibration circuit which provides a calibration signal employed to linearize a receiver channel. The receiver channel includes a plurality of receiver stages which receive the calibration signal and provide the distorted output signal which is intercepted and directed to a cubing circuit. The cubing circuit generates an error correction signal controlled by the feedback loop to cancel the distortion component of the distorted output signal. In the preferred embodiment, the feedback loop controls the amplitude and phase of the error correction signal while in another illustrative embodiment, only the amplitude of the error correction signal is controlled. Thus, the invention discloses a correction circuit arrangement for a receiver channel which provides a distortion corrected output signal by effectively removing the distortion generated by the receiver.