Advantest R9211C FFT Servo Analyzer

The Advantest R9211C FFT Servo Analyzer is a precision instrument for high-resolution frequency domain analysis and servo system characterization. It combines advanced FFT technology with specialized servo measurement capabilities, delivering accurate closed-loop and open-loop transfer function analysis across demanding mechanical, acoustic, and control system applications. The R9211C executes complex measurements with 130 dB dynamic range, inter-channel amplitude accuracy of ±0.1 dB, and phase coherence within ±1.0°.

– Technical Specifications

Frequency Response
• Frequency range: 10 mHz to 100 kHz
• Frequency resolution: 25 to 3200 lines with linear and logarithmic sweep options
• Resolution: 16-bit
• Dynamic range: 130 dB (servo analysis); 90 dB typical (spectrum analysis)
• Maximum input sensitivity: -140 dBV (typical, 2 kHz range)

Input Channels & Signal Conditioning
• Input channels: 2
• Input format: Differential and single-ended
• Input impedance: Approximately 1 MΩ / 100 pF (single-ended)
• Common-Mode Rejection Ratio (CMR): 50 dB or more (DC coupling, 50/60 Hz)
• Maximum differential input voltage: ±200 V
• Maximum common-mode signal voltage: ±200 V
• Input range: +30 dBV to -60 dBV (1 dB steps)
• Auto range optimization available
• Accelerometer power source: 4 mA current source, max. +18 V operating voltage

Servo Analysis
• Inter-channel amplitude difference: ±0.1 dB or less
• Inter-channel phase difference: ±1.0° or less
• Output impedance: 1 Ω or less for high actuator drive performance
• Independent DC offset and signal voltage control
• Sweep techniques: Swept Sine Sweep (SSS) and Band Multi-Sign (BMS) for high-speed measurement
• Measurement modes: Five-domain analysis with closed-loop to open-loop conversion
• Single-touch gain and phase margin measurement
• Curve fit and frequency response synthesis functions
• Internal summing amplifier for open-loop characteristic measurements
• Frequency table point servo measurement and up to five decades of log sweep

Analysis Capabilities
• Spectrum analysis modes: Waveform, spectrum, time-frequency analysis, frequency response function measurement

– Key Features

• High-speed servo measurement with SSS and BMS sweep techniques
• 16-bit resolution across 10 mHz to 100 kHz frequency span
• 130 dB dynamic range for low-level signal detection
• Automatic input range optimization
• Closed-loop to open-loop transfer function conversion
• Time-frequency analysis for acoustic and reverberant signal evaluation

– Typical Applications

• Servo system design and characterization
• Control loop stability and frequency response testing
• Acoustic and mechanical system analysis
• Actuator performance evaluation