Dual-modulation laser line-locking for wavelength modulation spectroscopy
AssigneeSouthwest Sciences Incorporated
InventorsDavid S. Bomse, Joel A. Silver
Life of this patent
Estimating the term…
Abstract
An improvement to a dual-modulation line-locking device for wavelength modulation spectroscopy employing a lowpass filter to generate a nonnormalized error signal and a bandpass filter and RMS-to-DC converter to generate a centering signal. When the error signal is approximately zero and the centering signal is large, the wavelength is coincident with the center of the absorption feature of the sample.
Claims24
In a dual-modulation line-locking device for wavelength modulation spectroscopy comprising a demodulator and wavelength control means, an improvement comprising:
- a lowpass filter receiving a signal from the demodulator and providing a signal to the wavelength control means;
- a signal conditioning filter receiving a signal from the demodulator;
- and
- an RMS-to-DC converter receiving a signal from said signal conditioning filter and generating a signal to the wavelength control means.
In a dual-modulation line-locking method for wavelength modulation spectroscopy employing a demodulated signal and wavelength control, an improved method comprising the steps of:
- (a) lowpass filtering the demodulated signal to generate a first wavelength control signal;
- (b) filtering the demodulated signal;
- and
- (c) RMS-to-DC converting the filtered signal and generating therefrom a second wavelength control signal.
Dependencies are inferred from the claim text.