Patent ID: 8112238

Claim:
A method of operating a spectrum analyzer having an yttrium-iron garnet (YIG) tuned filter (YTF), an internal noise source, and a memory device, the method comprising: performing an alignment of a tuning response of the YTF, the alignment comprising, (i) applying a noise signal generated by the internal noise source of the spectrum analyzer to the input of the YTF, (ii) applying a tuning current to the YTF to tune the YTF to a selected alignment frequency, (iii) measuring a value of a gain alignment parameter of the YTF while the noise signal is applied to the input of the YTF and the tuning current is applied to the YTF, (iv) storing the measured gain alignment parameter value in an alignment table in the memory device, and (v) repeating steps (ii) through (iv) for a plurality (N) of selected alignment frequencies in an operating frequency range of the YTF; receiving an externally-supplied signal at an input of the spectrum analyzer; tuning the YTF to an operating frequency for measuring a characteristic of the externally-supplied signal; and measuring the characteristic of the externally-supplied signal at the operating frequency using the YTF and a correction factor that is determined from one of the gain alignment parameter values in the alignment table.