A method for separating spectrums of an input signal having a first spectrum and a second spectrum by mixing the input signal at a first mixer with a first frequency to obtain a first mixed signal; mixing the input signal at a second mixer with second frequency to obtain a second mixed signal; displacing the first mixed signal and/or the second mixed signal up and down by the difference of the first and second frequency obtaining at least one lower auxiliary signal and at least one upper auxiliary signal, respectively; and extracting the first spectrum and/or the second spectrum using the lower auxiliary signal and/or the upper auxiliary signal as well as the first mixed signal and/or the second mixed signal. Further, measurement devices for separating spectrums are shown.

The invention relates to a method (1) for monitoring a rotating machine (100) of an aircraft, wherein a measurement signal is acquired from the rotating machine. According to the invention, instantaneous frequencies (f.sub.K(t)) of sinusoidal components of the measurement signal are estimated, and, using a computing module (12), a plurality of successive iterations are carried out in each of which: complex envelopes of the components are updated (C1), parameters of a model of a noise of the signal are updated (C21) on the basis of the envelopes, whether the model has converged from the preceding iteration to the present iteration is tested (C4), with a view to: o if not, carrying out a new iteration, o if so, performing a computation (D) of the complex envelopes on the basis of the iterations that have been carried out.

A digital filter for processing at least one input signal is described. The digital filter includes at least two filter parts that are separately formed from each other. The at least two filter parts are configured to process the at least one input signal in parallel which is received by the digital filter. A first filter part of the at least two filter parts is implemented in a first chip. A second filter part of the at least two filter parts is implemented in a second chip. Further, a measurement instrument is described.

A digital filter for processing at least one input signal is described. The digital filter includes at least two filter parts that are separately formed from each other. The at least two filter parts are configured to process the at least one input signal in parallel which is received by the digital filter. A first filter part of the at least two filter parts is implemented in a first chip. A second filter part of the at least two filter parts is implemented in a second chip. Further, a measurement instrument is described.

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.

Methods, devices, and systems for coherent time-gated residual spur characterization and correction in signal analyzers. In some cases, the method includes: displaying a signal on the display of the signal analyzer that is present without an input signal being provided to an input of the signal analyzer; establishing a predetermined amplitude threshold above which energy spikes in the signal being displayed on the display of the signal analyzer are considered spurious; automatically identifying one or more spurious energy spikes in the signal being displayed on the display of the signal analyzer based on the predetermined amplitude threshold; and automatically reducing or removing the one or more spurious energy spikes from the signal being displayed on the display of the signal analyzer. The method can be performed using one or more processors, application specific integrated circuits (ASICs), field-programmable gate array (FPGA), or other circuitry on any suitable signal analyzer.

A reliable method and apparatus for communications over AC power lines that may have substantial interference is disclosed. A controller can be plugged into an AC outlet and communicate with a device plugged into any other AC outlet over the power lines within the facility. The controller may perform an analysis of the interference that is present on the power lines that run throughout the facility. In some cases, the particular path for power line signals can be selected to reduce the potential for interference. In some cases, the controller has a front end that comprises a Fast Fourier Transform (FFT) module and a neural network. In addition, devices under the control of the controller may have neural networks that can be used in combination to form a collaborative neural network.

A signal detection methodology is provided to determine from a waterfall image where the signal occurred on the frequency spectrum, when it occurred, and what type of modulation the signal is. The methodology includes converting a waterfall image into a first binary image version of the waterfall image; removing noise spikes from the first binary image version of the waterfall image; removing vertical gaps in the first binary image to thereby create an intermediate image version of the first binary image; converting the intermediate image version of the first binary image into a second binary image; identifying location parameters of a signal of interest within the second binary image; and isolating, using the identified location parameters, the signal of interest in the waterfall image to generate an isolated image of the signal of interest.

A signal detection methodology is provided to determine from a waterfall image where the signal occurred on the frequency spectrum, when it occurred, and what type of modulation the signal is. The methodology includes converting a waterfall image into a first binary image version of the waterfall image; removing noise spikes from the first binary image version of the waterfall image; removing vertical gaps in the first binary image to thereby create an intermediate image version of the first binary image; converting the intermediate image version of the first binary image into a second binary image; identifying location parameters of a signal of interest within the second binary image; and isolating, using the identified location parameters, the signal of interest in the waterfall image to generate an isolated image of the signal of interest.