{"term":{"id":"04059","title":"multiplex spectrometer","longtitle":"IUPAC Gold Book - multiplex spectrometer","doi":"10.1351\/goldbook.M04059","code":"M04059","status":"current","abbrev":"<em>abbrev<\/em>: FTS","definitions":[{"id":1,"text":"A spectrometer in which a single photodetector simultaneously receives signals from different spectral bands which are specifically encoded. In the case of frequency multiplexing, each spectral band is modulated at a specific frequency. Decoding is achieved by filtering out, by electronic means, the corresponding signals. Frequency multiplexing may be realized by changing the path difference between the two interfering beams at a uniform rate. Fourier transform of the interferogram so obtained yields the spectrum. This method is called Fourier transform spectrometry (FTS).","links":[{"term":"Fourier transform spectrometry (FTS)","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/F02493"},{"term":"spectrometer","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/S05837"}],"sources":["PAC, 1995, 67, 1725. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-IX. Instrumentation for the spectral dispersion and isolation of optical radiation (IUPAC Recommendations 1995)' on page 1729 (https:\/\/doi.org\/10.1351\/pac199567101725)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/M04059\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/M04059\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/M04059\/plain"},"citation":"Citation: 'multiplex spectrometer' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.M04059","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-06-28T17:29:16+00:00"}}