The HP Agilent 8561B is a Spectrum Analyzer with a  50 Hz to 6.5 GHz Range DC Coupled; 100KHz to 6.5 GHz AC Coupled that features synthesized tuning, built-in frequency counter, digital bandwidths, AM/FM demodulator, & many optional features.

The HP Agilent 8561B, RF Programmable Spectrum Analyzer, offers excellent performance for RF design and service applications. The Agilent HP 8561B, Programmable Spectrum Analyzer, has a frequency range of 50Hz to 6.5GHz.

It has a synthesized tuning for drift-free, accurate measurements. Has a sensitivity of  - 130 dBm and digital bandwidths of 10, 30, and 100 Hz. The HP Agilent 8561B, RF Programmable Spectrum Analyzer, meet the MIL - T- 28800C specifications for ruggedness.