Abstract: The invention relates to a Hadamard spectrometer which enables the detection of a range of polyatomic gases or liquids for example using infrared absorption. The aim of the invention is to produce a spectrometer of this type which provides higher resolution, improved wavelength precision and an improved signal-to-noise ratio using conventional detector lines and which allows a small and compact design. To this end, a detector line (30) with a set interval (a) between the individual detector areas (31) is used for a detector unit (3), and a linear assembly (10) is also used for a light-emitting respective reflective assembly (1). The linear assembly includes (n) adjoining identical light sources (11, 12, 13, 14), n always remaining ≧3, which can be activated individually according to the Hadamard Principle.