HP / Agilent 3580A Spectrum Analyzer

The HP/Agilent 3580A is a low-frequency spectrum analyzer engineered for detailed spectral analysis in the audio and subsonic range. Operating from 5 Hz to 50 kHz, it delivers 80 dB dynamic range with resolution bandwidth as narrow as 1 Hz across all frequencies—20 mHz minimum in FFT mode. The instrument supports linear amplitude measurements from 100 nV to 20 V full scale, or logarithmic operation from +30 dBm to -150 dBm full scale. An internal tracking generator (Option 002 adds tracking oscillator output) enables stimulus-response testing without external signal sources. The CRT display stores two traces digitally for direct comparison. Adaptive sweep technology accelerates scan speed up to tenfold by applying user-defined thresholds, ideal for identifying anomalies in complex spectra. Sweep times span 0.1 to 2000 seconds across scan widths of 50 Hz to 50 kHz, with logarithmic sweep capability from 20 Hz to 43 kHz. Frequency response accuracy is ±3% from 5 Hz to 50 kHz. Input impedance is 1 Megohm shunted by 30 pF. The standard unbalanced input accepts ±100 V dc maximum and provides capacitive coupling. Output capability extends to 1 V RMS into 600 ohms, supporting both dBV and dBm/600 ohms measurement modes. An internal calibration signal enables amplitude verification. Noise performance depends on bandwidth and source resistance; 1/f surface noise dominates below 1 kHz.