Spectral Dynamics SD345-3B02 Spectrascope III Narrowband Spectrum Analyzer

Spectral Dynamics SD345-3B02 Spectrascope III Narrowband Spectrum Analyzer

The Spectral Dynamics SD345-3B02 is a benchtop narrowband spectrum analyzer from Spectral Dynamics Corporation of San Diego — a well-regarded manufacturer of dynamic signal analyzers widely used in vibration analysis, structural testing, and acoustic measurement. The SD345 Spectrascope III is a dual-section instrument combining a built-in CRT display with an extensive keypad-driven control interface covering spectral measurement, averaging, sensitivity, frequency translation, and plotter output functions. It is a self-contained FFT-based analyzer designed for both laboratory and field measurement applications.

Specifications & What's Included

• Manufacturer: Spectral Dynamics Corporation, San Diego, CA
• Model: SD345-3B02
• Series: Spectrascope III
• Type: Narrowband Spectrum Analyzer (FFT / Dynamic Signal Analyzer)
• Form Factor: Benchtop / portable rack-style enclosure, dual-section chassis
• Display: Built-in CRT with green phosphor graticule grid
• Front Panel Sections: X, Y, Function, Avg MI (averaging/mode), Panel, Plotter, Remote, Spectrum, Sensitivity, Translator, Range, Level, Signal — with LED-illuminated pushbutton keypad
• Rear Input: SIG IN — BNC connector (J1); TIME SYNC — BNC connector (J2)
• Rear Plotter Outputs: X (J3, BNC), Y (J4, BNC), Composite Video (J5, BNC), Pen Lift (J6, BNC)
• Rear Scope Outputs: Scope Y (J7, BNC), Scope X (J8, BNC)
• Rear Trigger/Sync: Sweep Trig (J9), Memory Period (J10), Gated Sweep Trig / Z Axis (J11), Mem Sync (J12) — BNC connectors
• Digital Interface: IEEE-488 / GPIB (Addressable) — rear panel
• Control Buses: Sense & Control (J7, D-sub multi-pin), Auxiliary (J8, D-sub multi-pin) — rear panel
• Power: IEC AC inlet, 10A SLO fuse, dual power switches (S1/S2) on rear panel
• Cooling: Large rear exhaust fan

Applications

The Spectral Dynamics SD345 Spectrascope III is a narrowband FFT spectrum analyzer designed for structural dynamics, vibration analysis, acoustic measurement, and general signal analysis in engineering and research environments. Spectral Dynamics was a pioneer in real-time digital signal analysis instrumentation, and the Spectrascope III series was widely used in aerospace, automotive, and mechanical engineering test labs from the late 1970s through the 1980s and into the 1990s for modal analysis, machine health monitoring, and noise and vibration characterization. The IEEE-488 / GPIB interface allowed the SD345 to be integrated into automated test systems and controlled by external computers — standard practice in instrumentation of that era. The built-in plotter outputs (X, Y, composite video, pen lift) supported connection to XY plotters and external displays for hard-copy data recording, which was the standard data output method before PC-based acquisition became dominant. Units like this remain sought after by legacy test system users, research institutions maintaining period-correct test setups, and engineers working on vibration or structural analysis applications that don't require modern PC-based systems.