Noise-figure meter

A noise figure meter is an instrument for measuring the noise figure of an amplifier, mixer, or similar device. An example instrument is the 1983-era Agilent 8970A. A noise figure meter is an instrument for measuring the noise figure of an amplifier, mixer, or similar device. An example instrument is the 1983-era Agilent 8970A. One way to perform the measurement is described on the Y-factor page. A noise-figure meter could automate that procedure as follows: A gated broadband noise source (such as an avalanche diode) drives the device under test. A measurement is made with the noise source on; another measurement with the noise source off. From those measurements and the characteristics of the noise source, the noise figure can be calculated. Some noise figure meters need a calibrated broadband noise source -- a noise generator. Several methods are used to generate broadband noise. Some methods require two sources: a 'hot' and 'cold' source. For high frequency measurements, the noise source will be embedded in a transmission line. Noise (electronics)#Thermal noise