Stanford Research SR785
Dynamic Signal Analyzer, DC - 102.4 kHz, 2 Ch.

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• MSRP: $15,950 | Available for Rental    GET QUOTE  

Product Overview

The Stanford Research SR785 Dynamic Signal Analyzer is a precision, two channel, full featured signal analyzer that offers state-of-the-art performance at a price that's less than half that of competitive analyzers. The SR785 is an ideal instrument for analyzing both mechanical and electrical systems. For measurements involving servo systems, control systems, acoustics, vibration testing, modal analysis, or machinery diagnostics, the SR785 has the features and specifications to get the job done.

Standard measurement groups include FFT, order tracking, octave, swept-sine, correlation, time capture, and time/histogram. The SR785 brings the power of several instruments to your application: a spectrum analyzer, network analyzer, vibration analyzer, octave analyzer and oscilloscope.

A unique measurement architecture allows the analyzer to function as a typical dual channel analyzer with measurements like cross spectrum, frequency response and coherence. Alternatively, the SR785 can be configured so that each input channel functions as a single channel analyzer with its own span, center frequency, resolution and averaging. This allows you to view a wide-band spectrum and simultaneously zoom in on spectral details. The same advanced architecture provides storage of all measurement building blocks and averaging modes. Vector averaged, rms averaged, unaveraged, and peak hold versions of all measurements are simultaneously acquired and can be displayed without re-taking data.

Features and Specifications of the Stanford Research SR785 Dynamic Signal Analyzer include:

• DC to 102.4 kHz bandwidth
• 90 dB dynamic range
• 145 dB dynamic range in swept-sine mode
• Order tracking
• 20-pole/20-zero curve fitting
• Real-time octave analysis
• Up to 32 Mbyte memory
• GPIB and RS-232 interfaces
• Instrument Modes:  FFT, Time/Histogram, Correlation, Octave, Swept-Sine, Order Tracking
• Frequency Domain Measurements:  Frequency Response, Linear Spectrum, Cross Spectrum, Power Spectrum, Coherence, Power Spectral Density
• Time Domain Measurements:  Time Record, Cross-Correlation, Auto-Correlation, Orbit
• Amplitude Domain Measurements:  Histogram, PDF, CDF
• FFT Resolution:  100, 200, 400, 800 lines
• Views:  Linear Magnitude, Log Magnitude, dB Magnitude, Magnitude Squared, Real Part, Imaginary Part, Phase, Unwrapped Phase, Nichols, Nyquist, Polar
• Units:  V, V², V²/Hz, V/vHz, meters, meters/s, meters/s², inches, inches/s, inches/s², mils, g, kg, lbs., N, dynes, pascals, bars, SPL, user-defined engineering units (EUs)
• Displays:  Single, Dual, Front/Back Overlay, Waterfall with Skew, Zoom and Pan, Grid On/Off
• Marker Functions:  Trace Marker, Dual-Trace Linked Marker, Absolute and Relative Marker, Peak Find, Harmonic Marker, Band and Sideband Marker, Waterfall Marker, Frequency-Damping Marker
• Averaging:  RMS, Vector, Peak Hold, Linear, Exponential, Equal Confidence (Octave), Preview Time Record, Percent Overlap Averaging, Overload Reject
• Triggering:  Continuous, Internal, External (Analog or TTL), Source, Auto/Manual Arming, GPIB, RPM Step, Time Step, Pre/Post Trigger Delay
• Source Outputs:  Sine, Two-Tone, Swept-Sine, White/Pink Noise, Burst Noise, Chirp, Burst Chirp, and Arbitrary
• Windows:  Hanning, Blackman-Harris, Flat-Top, Kaiser, Force/Exponential, User-Defined, +/-T/2, +/-T/4, T/2, Uniform
• User Math:  +, -, ×, /, Conjugate, Magnitude/Phase, Real/Imaginary, Sqrt, FFT, Inverse FFT, jO, Log, Exp, d/dx, Group Delay, A-, B-, C-Weighting, x/x-1, Trace 1 to 4, Vector Average, RMS Average, Peak Hold
• Analysis:  Harmonic, Band, Sideband, THD, THD + N, Limit Test with Pass/Fail, Data Table, Exceedance, Statistics, Curve Fit and Synthesis
• Time Capture:  Captures time data for later analysis (FFT or Octave). Up to 2 Msamples (8 Msamples optional) of data can be saved.
• Storage:  3.5", 1.44 Mbyte DOS formatted disk. Save data, setups and hard copy data.
• Hard Copy and Interfaces:  Print to Dot Matrix or PCL (LaserJet and DeskJet) printers. Plot to HP-GL or Postscript plotters. Print/Plot on-line (RS-232 serial, Centronics parallel or IEEE-488.2) or to disk file. EPS, GIF, PCX graphic formats also available for disk storage.
• Data Conversion Utility:  Data, waterfall and capture files can be converted to ASCII. Data files can also be converted to Universal File Format, SDF format or MATLAB MAT-File Format. SDF and SR780 files can be converted to SR785 format.
• DataViewer:  Windows based graphics program for viewing SR785 files. Graphs can be pasted to the clipboard or saved in PCX, BMP or GIF.
• Measurement Groups: 
  
• FFT
• Correlation
• Time Histogram
• Swept-Sine
• Order Tracking
• Frequency: 
• Range:   102.4 kHz or 100 kHz (both displays have the same range)
• FFT Spans:  195.3 mHz to 102.4 kHz or 191 mHz to 100 kHz. The two displays can have different spans and start frequencies.
• FFT Resolution:  100, 200, 400 or 800 lines
• Real-Time Bandwidth:  102.4 kHz (highest FFT span with continuous data acquisition and averaging)
• Accuracy:  25 ppm from 20 °C to 40 °C
• Dynamic Range: 
• Range:  90 dB typical, 80 dB guaranteed (FFT and Octave). 145 dB typical (Swept-Sine). Includes spurs, harmonics, intermodulation distortion, and alias products. Excludes alias responses at extremes of span.
• Harmonic Distortion: 
• Intermod Distortion: 
• Spurious: 
• Alias Responses: 
• Full Span FFT Noise Floor:  -100 dBfs typical (input grounded, >-30 dBV, Hanning window, 64 rms averages)
• Residual DC Response: 
• Amplitude Accuracy:
• Single Channel:  ±0.2 dB (excluding window effects)
• Cross Channel:  ±0.05 dB, DC to 102.4 kHz (frequency response measurement, both inputs on the same range, rms averaged)
• Phase Accuracy:
• Single Channel:  ±3.0 deg. relative to external TTL trigger (-50 dBfs to 0 dBfs, freq
• Cross Channel: 
• • ±0.5 deg. (DC to 51.2 kHz)
  • ±1.0 deg. (DC to 102.4 kHz)
  • (frequency response measurement, both inputs on same range, vector averaged)
• Single Inputs:
• Number of Inputs:  2
• Full-Scale Input Range:  -50 dBV (3.16 mVp) to +34 dBV (50 Vp) in 2 dB steps
• Maximum Input Level:  57 Vp
• Input Configuration:  Single-ended (A) or differential (A-B)
• Input Impedance:  1 MO + 50 pF
• Shield to Chassis: 
• Floating mode:  1 MO + 0.01 µF
• Grounded mode: 50 O (shields grounded in (A-B) mode)
• Max Shield Voltage:  4 Vp
• AC Coupling:  0.16 Hz cutoff frequency
• CMRR: 
• 90 dB at 1 kHz (input range
• 80 dB at 1 kHz (input range
• 50 dB at 1 kHz (input range =10 dBV)
• ICP Signal Conditioning:  
• Current source: 4.8 mA
• Open circuit voltage: +26 V
• A-Weight Filter:  Type 0 tolerance, ANSI standard S1.4-1983; 10 Hz to 25.6 kHz
• Crosstalk: 
• Input Noise: 
• Trigger Input:
• Modes:  Free Run, Internal, External, or External TTL
• Internal:  Level adjustable to ±100 % of input scale, positive or negative slope. Min. trigger level: 5 % of input range
• External: 
• Level adjustable to ±5 V in 40 mV steps, positive or negative slope.
• Input impedance: 1 MO
• Max input: ±5 V
• Min trigger amplitude: 100 mV
• External TTL:  Requires TTL level to trigger (low 3.0 V)
• Post-Trigger:  Measurement record is delayed up to 100,000 samples after the trigger.
• Pre-Trigger:  Measurement record starts up to 8000 samples prior to the trigger.
• Tachometer Input:
• Pulses Per Revolution:  1 to 2048
• RPM Accuracy:  ±50 ppm (typ)
• Tach Level Range:  ±25 V, ±5 V, TTL
• Tach Level Resolution:  20 mV @ ±25 V, 4 mV @ ±5 V
• Max Tach Input Level:  ±40 Vp
• Min Tach Pulse Width:  100 ns
• Max Tach Pulse Rate:  750 kHz (typ)
• Transient Capture:
• Mode:  Continuous data recording
• Maximum Rate:  262,144 samples/s for both inputs
• Maximum Capture Length: 
• 2 Msamples (single input)
• 8 Msamples with optional memory
• Octave Analysis: 
• Standards:  Conforms to ANSI standard S1.11- 1986, Order 3, Type 1-D
• Frequency Range (Band Centers): 
• Single Channel:
• 1/1 Octave:  0.125 Hz to 32 kHz
• 1/3 Octave:  0.100 Hz to 40 kHz
• 1/12 Octave:  0.091 Hz to 12.3 kHz
• Two Channels: 
• 1/1 Octave:  0.125 Hz to 16 kHz
• 1/3 Octave:  0.100 Hz to 20 kHz
• 1/12 Octave:  0.091 Hz to 6.17 kHz
• Accuracy: 
• Dynamic Range:  80 dB (1/3 Octave, 2 second stable average) per ANSI S1.11-1986
• Sound Level:  Impulse, Peak, Fast, Slow and L_eq per ANSI S1.4-1983 Type 0 and IEC 651-1979 Type 0
• Order Tracking:
• Delta Order:  0.0075 to 1
• Resolution:  up to 400 lines
• Amplitude Accuracy:  ±1 dB (typ)
• Displays:  Order map (mag. and phase), order track (mag. and phase), orbit
• Curve Fit and Synthesis:
• Type:  20 poles/20 zeros curve fit (non-iterative rational fraction)
• Order Selection:  Auto or manual
• Output Format:  Pole-zero, polynomial, pole-residue
• Source Output:
• Amplitude Range:  0.1 mVp to 5 Vp
• Amplitude Resolution:  0.1 mVp
• DC Offset: 
• Offset Adjust:  ±5 VDC (sine, two-tone, swept-sine)
• Output Impedance: 
• Sine Source:  
• • Amplitude Accuracy:  ±1 % of setting, 0 Hz to 102.4 kHz , 0.1 Vp to 5 Vp into High-Z load
  • Harmonics, sub-harm & spurious signals: 
• Two-Tone Source: 
• • Amplitude Accuracy:  ±1 % of setting, 0 Hz to 102.4 kHz, 0.1 Vp to 5 Vp into High-Z load
• Harmonics, sub-harm: 
• White Noise Source:  
• Time Record:  Continuous or burst
• Bandwidth:  DC to 102.4 kHz or limited to span
• Flatness: 
• Pink Noise Source:  
• Bandwidth:  DC to 102.4 kHz
• Flatness: 
• Chirp Source:
• Time Record:  Continuous or Burst
• Output:  Sine sweep across the FFT span
• Flatness: ±0.25 dB (1.0 Vp)

Other model of Stanford Research Dynamic Signal Analyzer is SR780.