Single beam frequency modulated dispersive analyzer

Claim 1

IN AN IMPROVED APPARATUS FOR SEGREGATING, FROM RADIATION FROM A SINGLE SOURCE, MONOCHROMATIC BEAMS DIFFERING IN WAVELENGTH: A SINGLE DETECTOR; A MONOCHROMATOR RECEIVING RADIATION ALONG A SINGLE COMMON PATH FROM THE SOURCE; SAID MONOCHROMATOR INCLUDING: (1) SINGLE COMMON DISPERSING MEANS (2) ALTERNATE DIRECTING MEANS, WITHIN THE MONOCHROMATOR AND SEPARATE FROM THE DISPERSING MEANS, POSITIONED TO RECEIVE THE RADIATION FROM THE SOURCE ALONG SAID SINGLE COMMON PATH AND TO DIRECT THE RADIATION TO THE DISPERSING MEANS ALONG TWO ALTERNATELY USED PATHS, WHEREBY RADIATION IS ALTERNATELY AND CYCLICALLY DIRECTED AT THE DISPERSING MEANS AT FIRST AND SECOND PRESELECTED ANGLES OF INCIDENCE, SAID ALTERNATE DIRECTING MEANS INCLUDING ESSENTIALLY ROTATING REFLECTIVE CHOPPING MEANS DISPOSED AT AN EFFECTIVE POSITION, RELATIVE TO THE REMAINDER OF THE ALTERNATE DIRECTING MEANS, TO PERIODICALLY AND ALTERNATELY INTERRUPT THE RADIATION RECEIVED ALONG SAID SINGLE COMMON PATH AND TO TRANSMIT THE RADIATION TO THE DISPERSING MEANS ALONG THE TWO RESPECTIVE ALTERNATELY USED PATHS, (3) AND MEANS FOR SELECTING, FROM RADIATION LEAV-