An arrangement for signal analysis provides at least one central data-processing unit and a screen unit connected to the at least one central data-processing unit, wherein the central data-processing unit calculates a spectrum and a spectrogram from a digitized signal. The at least one central data-processing unit is embodied in such a manner that it controls the screen unit in such a manner that the spectrogram of the digitized signal, the characteristic of the spectrum of the digitized signal and the characteristic of the digitized signal present in the time domain can be displayed together on the screen unit.

Apparatus and methods for phase tracking an oscillatory signal are provided. In one arrangement, an input signal is received. First and second reference oscillatory signals are received at the frequency of a target frequency component of the input signal. The first and second reference oscillatory signals are phase shifted relative to each other. Weights of a weighted sum of the first and second reference oscillatory signals are iteratively varied to match the weighted sum to the input signal. The weights of the matched weighted sum are used to provide real time estimates of the phase of the target frequency component of the input signal.

A method for correcting a time-dependent measurement signal generated by means of an electric motor coupled on the output side to a transmission with regard to the influence of a variable output load and a variable rotational speed includes: tapping a time-varying measurement signal which is dependent on a torque of the motor transmission unit; generation of a useful signal, which is free of any DC component, from the measurement signal; interval-by-interval determination of RMS values from the measurement signal; generation of a load-corrected useful signal by an interval-by-interval division of the useful signal, which is free of any DC component, by the interval-specific RMS values; time-resolved determination of the rotational frequency of the motor from the measurement signal; scaling the load-corrected useful signal to the mean rotational frequency to generate a corrected measurement signal, and, use of the corrected measurement signal for fault detection of the motor transmission unit.

A method for correcting a time-dependent measurement signal generated by means of an electric motor coupled on the output side to a transmission with regard to the influence of a variable output load and a variable rotational speed includes: tapping a time-varying measurement signal which is dependent on a torque of the motor transmission unit; generation of a useful signal, which is free of any DC component, from the measurement signal; interval-by-interval determination of RMS values from the measurement signal; generation of a load-corrected useful signal by an interval-by-interval division of the useful signal, which is free of any DC component, by the interval-specific RMS values; time-resolved determination of the rotational frequency of the motor from the measurement signal; scaling the load-corrected useful signal to the mean rotational frequency to generate a corrected measurement signal, and, use of the corrected measurement signal for fault detection of the motor transmission unit.

A measurement of phase frequency response of a device under test (DUT), wherein the DUT is characterized by a set of switchable configurations, comprises choosing the steps of a particular configuration of the DUT having nominal parameters as a reference configuration, measuring an amplitude frequency response A.sub.ref (f) and a phase frequency response ϕ.sub.ref(f) of the reference configuration, processing all configurations of the DUT which are different from the reference configuration, one after another, by measuring an amplitude response A(f) of the configuration being processed, calculating a minimum phase difference response Δϕ.sub.min (f); and calculating for each configuration, a phase frequency response ϕ(f) of the respective configuration which is being processed, in accordance with ϕ(f) =ϕ.sub.ref(f)+Δϕ.sub.min(f).

A test and measurement instrument includes a first channel input for accepting a first input signal, a second channel input for accepting a second input signal, a spectrogram processor for producing a first spectrogram from the first input signal and for producing a second spectrogram from the second input signal, and a display for simultaneously showing the first spectrogram and the second spectrogram. Methods are also described.

The invention relates to a method and a device for estimating an angle of arrival of an incident radio signal in relation to a predetermined reference direction by using a set of N receiving paths comprising at least one directional antenna pointing in N different receiving directions, wherein only one sub-set of at least two receiving paths with adjacent antenna directions in said set of antennas delivers a measured power at reception. The device comprises modules suitable for: determining a number of receiving paths delivering a measured power forming said sub-set, and a reference index corresponding to a first receiving path in a direction in which extends the set of antenna directions of said sub-set; selecting the measured powers and obtaining a value to attribute to the non-measured powers to form a completed power signal; by applying a discrete Fourier transform (DFT) to said completed power signal, calculating at least one transformed value among the transformed values corresponding to a first, second, and third frequency line of the DFT; and, using the transformed value(s), applying an estimator of the angle of arrival, depending on the reference index.

The invention relates to a method and a device for estimating an angle of arrival of an incident radio signal in relation to a predetermined reference direction by using a set of N receiving paths comprising at least one directional antenna pointing in N different receiving directions, wherein only one sub-set of at least two receiving paths with adjacent antenna directions in said set of antennas delivers a measured power at reception. The device comprises modules suitable for: determining a number of receiving paths delivering a measured power forming said sub-set, and a reference index corresponding to a first receiving path in a direction in which extends the set of antenna directions of said sub-set; selecting the measured powers and obtaining a value to attribute to the non-measured powers to form a completed power signal; by applying a discrete Fourier transform (DFT) to said completed power signal, calculating at least one transformed value among the transformed values corresponding to a first, second, and third frequency line of the DFT; and, using the transformed value(s), applying an estimator of the angle of arrival, depending on the reference index.

A method for providing a frequency of an electrical quantity in an electrical power system comprises obtaining (30), with respect to a first time, a first discrete Fourier transform, DFT, phasor of an electrical quantity in the electrical power system, estimating (32) a second DFT phasor at a time interval before the first time, where the time interval depends on an approximated frequency, and determining (34) the frequency at the first time based on the first and the second DFT phasor.

A method for providing a frequency of an electrical quantity in an electrical power system comprises obtaining (30), with respect to a first time, a first discrete Fourier transform, DFT, phasor of an electrical quantity in the electrical power system, estimating (32) a second DFT phasor at a time interval before the first time, where the time interval depends on an approximated frequency, and determining (34) the frequency at the first time based on the first and the second DFT phasor.