Patent ID: 7429860

Claim:
An apparatus for performing spectral analysis of a sample, the apparatus comprising: a. a data acquisition system configured to measure a signal emitted from the sample in response to excitation energy applied thereto, and to average the measured signal over a plurality of measurements to generate an averaged signal for the sample; b. a data processing system including: a noise-reduction pre-processor configured to generate a noise-reduced signal from the averaged signal by creating a vector space from said averaged signal, and generating one or more singular values and corresponding eigenvectors of a correlation matrix constructed within said vector space, said vector space containing a noisefree signal subspace and a noise subspace, said singular values including noisefree singular values associated with said noisefree signal subspace, and noise singular values associated with said noise subspace; and a spectral estimator configured to generate a spectrum for the sample by converting said noise-reduced signal into a frequency domain; and c. a control system configured to identify, in a graph of the singular values of the correlation matrix constructed within the vector space created from the averaged signal, a gap between a smallest noisefree singular value and a first noise singular value, so as to request the data acquisition system to perform additional measurements of the signal emitted from the sample if no such separation gap can be identified, and to prevent further measurements of the signal emitted by the sample from being made by the data acquisition system if the gap has appeared and is stable.