Knowledge Bank

The recently developed ""Fourier Transform Millimeter Wave Spectrometer"" (FT-MMW) employs a technique of frequency switching which is different from the commonly used amplitude switching method for FT-Spectrometers in the centimeter wave range. Frequency switching is achieved by $180\circ$ phase modulation to generate two different sidebands of the master oscillator frequency in the microwave range. Extension of this technique to the millimeter wave range succeeds through frequency multiplication. The application is presently limited to the observation of collision-induced line broadening. Other applications will be possible in the future.