When the signal linewidth is significantly greater than the spectral resolution, the effect can be ignored and one can assume that the measured resolution is the same as the signal resolution. As a result, the observed resolution is the convolution of the two sources, It is important to understand that the observed signal ( S o) is not solely dependent on the spectral resolution of the spectrometer ( R) but it is also dependent on the linewidth of the signal ( S r). The detector determines the maximum number and size of discreet points in which the spectrum can be digitized.
The diffraction grating determines the total wavelength range of the spectrometer. The slit determines the minimum image size that the optical bench can form in the detector plane. In dispersive array spectrometers, there are 3 main factors that determine the spectral resolution of a spectrometer: the slit, the diffraction grating, and the detector. For example, if a spectrometer with a wavelength range of 200nm had a spectral resolution of 1nm, the system would be capable of resolving a maximum of 200 individual wavelengths (peaks) across a spectrum. The spectral resolution of a system determines the maximum number of spectral peaks that the spectrometer can resolve. One of the most important characteristics of a spectrometer is the spectral (or optical) resolution.