Abstract: A method is disclosed for demultiplexing a signal. The method comprises receiving the signal being a sum of at least two sub-signals, whereby each sub-signal comprises a different repetitive pattern. The method also comprises sampling the signal during a time period, whereby the time period is such that the different repetitive patterns of each sub-signal occur at least once and whereby at least sub-signals are periodic during with a different specific frequency. The method further comprises periodically expanding the signal in a Fourier series and obtaining the different complex spectral components of the periodically expanded signal.

Abstract: A method is disclosed for demultiplexing a signal. The method comprises receiving the signal being a sum of at least two sub-signals, whereby each sub-signal comprises a different repetitive pattern. The method also comprises sampling the signal during a time period, whereby the time period is such that the different repetitive patterns of each sub-signal occur at least once and whereby at least sub-signals are periodic during with a different specific frequency. The method further comprises periodically expanding the signal in a Fourier series and obtaining the different complex spectral components of the periodically expanded signal.

Abstract: A linear time-invariant system modeling apparatus comprises a processing resource arranged to receive, when in use, model data constituting to a model of a linear time-invariant system. The model data includes residual value data and scattering data. The processing resource is arranged to perform, when in use, a single value decomposition in respect of the scattering data; the scattering data corresponds, when expressed in matrix form, to a scattering matrix in a state-space representation of the model. The processing resource is also arranged to use, when in use, a result of the single value decomposition in order to generate residual value modification data. The residual value modification data is applied to the residual value data, the residual value data corresponding, when expressed in the matrix form, to a residual value matrix in the state-space representation of the model.

Abstract: A linear time-invariant system modeling apparatus comprises a processing resource arranged to receive, when in use, model data constituting to a model of a linear time-invariant system. The model data includes residual value data and scattering data. The processing resource is arranged to perform, when in use, a single value decomposition in respect of the scattering data; the scattering data corresponds, when expressed in matrix form, to a scattering matrix in a state-space representation of the model. The processing resource is also arranged to use, when in use, a result of the single value decomposition in order to generate residual value modification data. The residual value modification data is applied to the residual value data, the residual value data corresponding, when expressed in the matrix form, to a residual value matrix in the state-space representation of the model.