Broad-Band Discriminators for ATE Measurement of Sideband Noise

Techniques for measurement of carrier noise sidebands are analyzed relative to their applicability to automated test equipment. Resonant cavity discriminators are shown to be useful for narrow-band high sensitivity requirements at microwave frequencies. Interferometer discriminators cover the 10 MHz to 18 GHz spectrum with only four bridges. Two transmission lines provide -120 dBc/Hz sensitivity. If four lines are used the sensitivity is -130 dBc/Hz. Techniques for further improvement are also described.