HP / Agilent 3581A Wave Analyzer

The HP/Agilent 3581A Wave Analyzer is a benchtop signal analysis instrument for precision measurement and resolution of individual frequency components in the audio band. It identifies and quantifies harmonics, spurious signals, and distortion products through narrow-bandwidth selective analysis, supported by an Automatic Frequency Tracking (AFT) circuit that maintains lock on drifting signals. The 5-digit LED frequency readout updates five times per second with 1 Hz resolution across the 15 Hz to 50 kHz range. Amplitude sensitivity spans 0.1 µV rms to 100 V rms with noise sidebands suppressed >70 dB below CW signals at 10 bandwidths offset. An analog meter with mirror backing offers four selectable scales—two linear voltage and two logarithmic (90 dB or 10 dB)—displaying results in dBV, dBm, or rms volts. Five selectable bandwidths enable adaptive resolution, while AFT pull-in range exceeds 5× bandwidth for 3–100 Hz settings and 800 Hz for 300 Hz bandwidth, with ±800 Hz hold-in range. Dynamic range reaches 80 dB for logarithmic measurements. An internal calibration signal verifies amplitude to ±1.5% accuracy at 10 kHz and frequency accuracy. Universal auto-sensing power accepts optional internal rechargeable battery (Option 001, 90-day warranty) for portable operation. Rear-panel outputs include X-Y recorder drive voltage and tracking oscillator/BFO at 600-ohm unbalanced (3581A) or 600-ohm balanced configuration (3581C with audio monitor).