ABSTRACT
Bolometric signal detectors respond simply to the power level of a signal. Heterodyne detection systems produce output which contains information about the frequency distribution of incident signal power. They are therefore of particular value when we wish to determine the power frequency spectrum of a signal. A complete heterodyne detection system is usually called a heterodyne receiver. The detecting element in a heterodyne system is called a mixer. This is because it ‘mixes’ together two input signal frequencies to produce an output at another frequency. One of the simplest, and most commonly used, forms of mixer is a diode.
