HP3581A Wave Analyzer 15 Hz to 50 kHz
The Hewlett Packard 3581A Wave Analyzer resolves and measures the amplitude and frequency of spectral components. This instrument offers accurate amplitude and good frequency resolution in the form of a portable, easy-to-use measuring tool. Since not all signals originate from a stable frequency source, the HP 3581A incorporates an AFT circuit which locks to a drifting signal for stable, accurate measurements.
This Wave Analyzer came to us from a retiring electrical engineer who used this in his calibration and product development electronics lab.