A current detector and a detection unit are provided. The current detector is connected to at least one of drive current lines of a rotary machine. The detection unit performs an orthogonal detection on a main frequency detected by the current detector, and extracts a magnitude of a sideband wave. Then, a state of the rotary machine is diagnosed from the magnitude of the extracted sideband wave.

A remote photoplethysmography (RPPG) system for estimating vital signs of a person is provided. The RPPG system is configured to receive a set of imaging photoplethysmography (iPPG) signals measured from different regions of a skin of a person. The RPPG system is further configured to determine frequency coefficients at the frequency bins of the quantized frequency spectrum of the measured iPPG signals by minimizing a distance between the measured iPPG signals and corresponding iPPG signals reconstructed from the determined frequency coefficients, while enforcing joint sparsity of the determined frequency coefficients subject to the sparsity level constraint, such that the determined frequency coefficients of different iPPG signals have the non-zero values at the same frequency bins; and output one or a combination of the determined frequency coefficients, the iPPG signals reconstructed from the determined frequency coefficients, and a vital sign signal corresponding to the reconstructed iPPG signals.

A sensing system and a sensing signal measuring method thereof are provided. The sensing system includes a signal source, a connecting device, a frequency sweep circuit, and a controller. In the method, the signal source is activated to generate a specific signal. The controller controls the frequency sweep circuit to switch a frequency band of a frequency sweep signal to a first frequency band corresponding to each of a plurality of types of multi-point sensors. The controller receives a sensor signal of each multi-point sensor through the connecting device, where the sensor signal is a variation of a measurement signal output by each multi-point sensor in response to the specific signal and the frequency sweep signal. The controller executes an adaptive algorithm on the sensor signal to construct a correspondence between an eigenvalue of each multi-point sensor and a location of the first frequency band, and records the correspondence.

A sensing system and a sensing signal measuring method thereof are provided. The sensing system includes a signal source, a connecting device, a frequency sweep circuit, and a controller. In the method, the signal source is activated to generate a specific signal. The controller controls the frequency sweep circuit to switch a frequency band of a frequency sweep signal to a first frequency band corresponding to each of a plurality of types of multi-point sensors. The controller receives a sensor signal of each multi-point sensor through the connecting device, where the sensor signal is a variation of a measurement signal output by each multi-point sensor in response to the specific signal and the frequency sweep signal. The controller executes an adaptive algorithm on the sensor signal to construct a correspondence between an eigenvalue of each multi-point sensor and a location of the first frequency band, and records the correspondence.

Systems, devices, software, and methods of the present invention enable frequency-based signal power analyses in software suitable for signal with either stationary and non-stationary spectrums. The methods that may be used throughout various systems including transmitters receivers, repeater, controllers, monitors, etc. and in software simulators to enable various signal power calculations and analyses, such as frequency spectrum analysis, throughout operating systems and that may be consistently applied in system design and operation simulations in a wide range of applications, such as interference and spectrum monitoring or clearance, object tracking, transmission channel and noise analyses, radiated power analysis, signal boundary interference, satellite downlink signal identification, pulsed radar monitoring, audio detection and identification, etc.

A method for detecting a plurality of useful signals in a total signal. The useful signals correspond to radiofrequency signals emitted by different terminals in a multiplexing frequency band. A plurality of spectrograms calculated that have a compensated linear frequency drift and are respectively associated with different linear frequency drift values. For each analysis frequency and each spectrogram, time envelope filtering of the values is performed at the different times for analyzing the spectrogram at the analysis frequency using a filter representing a reference time envelope of the useful signals. A useful signal is detected at an analysis time and at an analysis frequency in response to a verification of a predefined detection criterion by the value from a spectrogram resulting from filtering at the analysis time and at the analysis frequency.

A method for detecting a plurality of useful signals in a total signal. The useful signals correspond to radiofrequency signals emitted by different terminals in a multiplexing frequency band. A plurality of spectrograms calculated that have a compensated linear frequency drift and are respectively associated with different linear frequency drift values. For each analysis frequency and each spectrogram, time envelope filtering of the values is performed at the different times for analyzing the spectrogram at the analysis frequency using a filter representing a reference time envelope of the useful signals. A useful signal is detected at an analysis time and at an analysis frequency in response to a verification of a predefined detection criterion by the value from a spectrogram resulting from filtering at the analysis time and at the analysis frequency.

A method of designing a filter to meet a set of specifications. The set of specifications is received, and a filter design is established. Analysis of the filter design is performed by: determining a part admittance matrix; determining a circuit admittance matrix based on the part admittance matrices; reducing interior nodes of the circuit admittance matrix; reducing algebraic nodes to transform the circuit admittance matrix into a Green's Function; evaluating the Green's Function to determine a circuit exterior node admittance matrix; and transforming the circuit exterior node admittance matrix to a circuit scattering matrix. The circuit scattering matrix is compared to the set of specifications to determine whether the filter design is satisfactory. When a determination is made that the design is not satisfactory, the filter design is modified and the process is repeated. When a determination is made that the design is satisfactory, a filter design description is output.

A method of designing a filter to meet a set of specifications. The set of specifications is received, and a filter design is established. Analysis of the filter design is performed by: determining a part admittance matrix; determining a circuit admittance matrix based on the part admittance matrices; reducing interior nodes of the circuit admittance matrix; reducing algebraic nodes to transform the circuit admittance matrix into a Green's Function; evaluating the Green's Function to determine a circuit exterior node admittance matrix; and transforming the circuit exterior node admittance matrix to a circuit scattering matrix. The circuit scattering matrix is compared to the set of specifications to determine whether the filter design is satisfactory. When a determination is made that the design is not satisfactory, the filter design is modified and the process is repeated. When a determination is made that the design is satisfactory, a filter design description is output.

Conventional real-time spectrum analyzers have a degree of technical complexity in the hardware which increases disproportionately as the analysis bandwidth increases for Fourier transformations of the measured sampling values. When using high analysis bandwidths, a detailed resolution is not needed of each analyzed individual frequency on the time plane at the same time; instead, detection of the presence of short pulses can be important as well. For this application, mixing sampling values on the time plane using a variable auxiliary frequency allows the sampling rate to be reduced, in that the bandwidth is maintained but a compression is carried out on the time plane. A very high time resolution which far exceeds the capabilities of conventional real-time spectrum analyzers can additionally be achieved overall for the analysis bandwidth, the time resolution then being computationally assignable to the individual frequencies for signal forms, in particular pulses, which occur in practice.