The HP/Agilent 35665A is a dual-channel dynamic signal analyzer delivering FFT, octave, and correlation analysis across DC to 102.4 kHz in single-channel mode, with dual-channel capability extending to 51.2 kHz. The instrument operates with real-time bandwidth of 32 kHz in single-channel operation and 16 kHz per channel in dual-channel mode, supporting 100, 200, 400, and 800-line FFT resolution. It combines spectrum analysis, network analysis, vibration measurement, and acoustics functionality with selectable measurement modes including time capture, cross-correlation, histogram analysis, power spectral density, and optional swept-sine measurements exceeding 130 dB dynamic range. The 35665A accepts ICP-type accelerometers and direct electrical signals on two front-panel BNC inputs with AC or DC coupling and a 1 Hz high-pass corner frequency. Standard onboard memory stores eight setup states plus waterfall data; optional expansion to 6 MB supports time-capture files, octave analysis waterfalls up to 49,000 1/3-octave spectra, and executable BASIC programs. A built-in 1.44 Mbyte 3.5-inch flexible disk drive enables permanent storage of spectra and ASCII data export. FFT mode delivers 72 dB dynamic range; octave mode provides 80 dB for ranges above 50 mV per ANSI S1.11-1986. Optional capabilities include computed order tracking for rotating machinery, curve fit synthesis for design optimization, and arbitrary waveform signal generation.
Technical Specifications
• Frequency range: 244 µHz to 102.4 kHz (single-channel); 122 µHz to 51.2 kHz (dual-channel); actual frequency response 195.31 mHz to 102.4 kHz
• Real-time bandwidth: 32 kHz (single-channel); 16 kHz per channel (dual-channel)
• FFT resolution: 100, 200, 400, 800 lines
• Dynamic range: 72 dB (FFT mode); >130 dB typical (swept-sine); 80 dB (octave mode, ranges >50 mV)
• Input connectors: Two front-panel BNC (ICP accelerometers or direct signals)
• Input coupling: AC (1 Hz -3 dB corner) or DC
• Internal memory: Standard onboard RAM for waterfalls plus eight setup states; optional up to 6 MB
• Data storage: 1.44 Mbyte 3.5-inch floppy disk drive
– Key Features
• Parallel-filter octave analysis (1/1, 1/3, 1/12-octave per ANSI S1.11)
• Auto-correlation and cross-correlation analysis
• Time-domain and histogram measurement modes
• Linear spectrum and cross-spectrum computation
• Optional swept-sine for elevated signal-to-noise ratios
• Optional computed order tracking for machinery diagnostics
– Typical Applications
• Vibration analysis
• Acoustic measurement and sound level characterization
• Control systems frequency response testing
• Rotating machinery diagnostics
– Compatibility & Integration
MS-DOS compatible floppy disk drive enables direct ASCII data exchange with external systems.
