The Stanford Research SR785 is a dual-channel dynamic signal analyzer designed for real-time frequency and time-domain measurement of dynamic signals. It delivers 16-bit resolution across configurable sampling rates up to 256 kS/s per channel, with dynamic range exceeding 90 dB typical. The instrument performs FFT-based spectrum analysis, coherence measurement, order tracking, harmonic analysis, and third-octave band analysis—making it suitable for vibration characterization, acoustic testing, control system evaluation, and general signal processing across mechanical and electrical systems.
Technical Specifications
Signal Acquisition
• Dual-channel differential inputs
• Input impedance: 1 MΩ || 20 pF (typical)
• Input voltage range: ±10 mV to ±10 V peak, selectable
• A/D converter: 16-bit resolution
• Sampling rate: Up to 256 kS/s per channel
• Dynamic range: >90 dB (typical)
• Frequency range: DC to 102.4 kHz
• Spectral resolution: 3200 lines
Analysis Capabilities
• FFT, Power Spectral Density, Power Spectrum, Cross Spectrum, Coherence
• Frequency Response Function (FRF) measurement
• Order analysis for rotating machinery and linear systems
• Third-octave band analysis
• Harmonic content and distortion measurement
• Waveform capture, time-domain averaging, transient recording
• Waterfall and orbit displays
Averaging & Processing
• Linear, exponential, and RMS averaging modes
• Windowing: Hanning, Flat Top, Force, user-defined
• Advanced mathematical functions for data manipulation
• Real-time processing with immediate results
– Key Features
• Built-in function generator with sine, chirp, and random outputs
• Triggering: external, software, and signal-level options
• Internal memory for measurement data and setups
• High-resolution integrated color display
• GPIB (IEEE 488.2), RS-232, and parallel printer interfaces
• Analog outputs for external monitoring and control
• Trigger input/output connectivity
– Typical Applications
• Mechanical vibration and modal analysis
• Acoustic testing and measurement
• Control system development and validation
• Rotating machinery diagnostics
• General-purpose dual-channel signal characterization
– Compatibility & Integration
GPIB remote control and data transfer. RS-232 serial communication. Centronics parallel printer output for documentation.
