The 8444A Tracking Generator is a tracking signal source for use with the 8554B and 8555A Spectrum Analyzers. Provides a swept source for frequency response measurements, and a constant amplitude signal for a frequency counter input. Allows for swept frequency tests over the 500kHz to 1250MHz frequency range. Dynamic range is greater than 90 dB from spectrum analyzer 1 dB gain compression point to average noise level (approx. -10 dBm to 100 dBm).