Daimler-Benz Aerospace Ag

Daimler Chrysler Ag

Eads Deutschland Gmbh

Franz Herrmann

Manfred Schuster

The invention concerns a method for generating calibration signals for calibrating spatially remote signal branches of antenna systems. In accordance with the invention, a base signal is generated by mean of a timer and is fed to a distributor unit for distribution of the base signal to amplifier circuits on the signal distribution lines respectively allocated to them. At the output of the amplifier circuits, a calibration signal is generated respectively via amplification of the base signal within a specifiable upper amplitude limit and a specifiable lower amplitude limit, which is fed to the respective feed-in point of the signal branch to be calibrated that is allocated to an amplifier circuit.

Method for generating calibration signals for calibrating spatially remote signal branches of antenna systems

A method for determining a frequency of a signal includes transforming the analog signal to the complex frequency range through a digital filtering, preferably a FFT, so that result vectors with amplitude and phase components are generated in the frequency range. As a result, a continuous sequence of transformation intervals (FFT intervals) develops within a measuring interval that can be predetermined. Subsequently, pairs of result vectors, which belong to the same predetermined frequency, are selected from predetermined transformation intervals (FFT intervals). Associated phase differences are then formed from which a weighted phase difference is determined. The weighted phase difference is used to correct the signal frequency determined from the amplitude spectrum. This method permits very accurate frequency measuring, especially for pulsed HF signals.

Method for determining the frequency of a signal

A direction-finding method for determining an incident angle of a high-frequency electromagnetic signal in a system including at least two receiving antennas spaced apart by a known distance. the antenna output signals of the at least two receiving antennas are converted, together (in accordance with a multiplexing procedure) or individually, into the frequency domain through a Fourier transformation, followed by a conversion into an IF range and an A/D conversion. In this range, the phase difference between the output signals is determined and the signal frequency of the incident wave is determined through a phase-sequence analysis. The incident angle of the incident wave is determined from the phase difference and the signal frequency.

Direction-finding method for determining the incident direction of a high-frequency electromagnetic signal

A method for detecting a pulsed usable signal that particularly includes the highest frequencies and possesses a poor signal/noise ratio. First an analog, frequency-limited input signal that corresponds to the usable signal to be detected is formed from the analog input signal through analog filtering. This signal is then converted into a series of digital phase values through a phase/digital converter. First phase difference values are formed from these digital phase values by parallel or serial signal processing, and second phase difference valves are formed from these first difference values. Absolute values of the second difference values are then supplied via a digital low-pass filter to a comparator having hysteresis. There, an output signal that can be digitally utilized and corresponds to the pulsed usable signal is formed by predeterminable threshold values.

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Oepfingen, Germany

Franz Herrmann