High sensitivity noise measurement with a correlation spectrum analyzer

A spectrum analyzer with enhanced sensitivity has been built and used in noise measurements. It is based on the processing of the input signal by two independent channels in parallel and takes advantage of the incoherent property of the noise in each of the two input stages. The instrument has demonstrated an improvement in sensitivity of at least 50 dB with respect to a traditional system, and therefore can measure low input signals down to the hundred pV//spl radic/Hz range.