SRS Labs Stereo System SR785 User Manual

STANFORD RESEARCH SYSTEMS  
SRS  
SR785  
Two Channel Dynamic  
Signal Analyzer  
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Fast Responsive Marker  
• Find Max/Min or track peaks  
• THD, THD + N  
• Band, sideband, harmonic power  
• Waterfall  
Standard Measurement Modes  
• FFT  
• Swept-Sine  
On-Line Help  
• Frequency and damping  
• Peak find  
Locate information on any  
topic, browse specifications,  
examine remote commands -  
all from the front panel.  
• Octave  
• TIme/Histogram  
• Order Tracking  
• Time Capture  
• Absolute and relative  
• Statistics  
PC (XT) Keyboard Input  
Enter text and annotations  
quickly and easily.  
Input Channels  
• Dual ADCs provide 102.4 kHz bandwidth on both  
channels simultaneously.  
• -50 dBV max full scale input sensitivity  
• Built-in ICP power supply for accelerometers  
• Switchable analog A-weighting filters  
• Engineering units  
User Math  
Build powerful custom  
measurements by directly  
entering equations.  
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SR785 Two Channel Dynamic  
Signal Analyzer  
FFT Spectrum Analysis  
The SR785 Two Channel Dynamic Signal Analyzer is a  
precision, full-featured signal analyzer that offers  
This allows you to view a wideband spectrum and  
simultaneously zoom in on spectral details.  
state-of-the-art performance and a wide selection of features  
at a price that's less than half that of competitive analyzers.  
Building on its predecessor, the SR780, the SR785  
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.  
incorporates new firmware and hardware that make it the  
ideal instrument for analyzing both mechanical and electrical  
systems. Whether your measurements involve modal analysis,  
machinery diagnostics, vibration testing, servo systems,  
control systems, or acoustics, 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 SR785 to  
function as a typical dual channel analyzer with measure-  
ments like cross spectrum, frequency response, coherence,  
etc. Alternatively, the instrument can be configured so that  
each input channel functions as a single channel analyzer with  
its own span, center frequency, resolution, and averaging.  
Use the SR785 to monitor the fundamental and  
harmonics of your signal. Total harmonic power  
and THD are calculated in real-time for fast,  
accurate analysis.  
Averaging  
The SR785 comes equipped with a wide selection of  
averaging techniques to improve your signal to noise ratio.  
Choose RMS averaging to reduce signal fluctuations, vector  
averaging to actually eliminate noise from synchronous  
signals, or peak hold averaging. In the order-tracking  
measurement group, time averaging is available. Both linear  
and exponential averaging are provided for each mode.  
The SR785 is so fast, there's no need for a separate "fast  
averaging" mode. Averaging is always fast, and the display  
update rate is never sacrificed to increase the averaging rate.  
For instance, in a full span FFT measurement with a 4 ms  
Bottom display shows a wideband FFT, while the  
top display shows a narrowband FFT of the same  
signal. The sideband marker has been selected for  
calculation of the total sideband power.  
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time record, 1000 averages take exactly 4 seconds, during  
which the SR785 still operates at its maximum display rate.  
For impact testing, the average preview feature allows each  
time record or spectrum to be accepted or rejected before  
adding it to the measurement.  
The SR785 tracks up to 400 orders simultaneously.  
You can display the amplitude profile of any two  
orders in tracked order mode.  
View order maps or track individual orders with the  
SR785.  
Order Tracking  
Order tracking is used to evaluate the behavior of rotating  
machinery. Measurement data is displayed as a function of  
multiples of the shaft frequency (orders), rather than absolute  
frequency. Combined with a waterfall plot, the SR785  
provides a complete history or "order map" of your data as a  
function of time or RPM. Using the slice feature, the ampli-  
tude profile of specific orders in the map can be analyzed.  
In tracked order mode the intensity of individual orders vs.  
RPM is measured. Unlike other analyzers, there’s no need to  
track a limited number of orders to ensure full speed  
measurements. The SR785’s speed allows simultaneous  
tracking of up to 400 orders.  
Run-up and run-down measurements are available in both  
polar and magnitude/phase formats. RPM profiling is  
Run-up and run-down measurements in both polar  
and bode formats are available.  
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provided to monitor variations of RPM as a function of time.  
And a complete selection of time and RPM triggering modes  
is included allowing you to make virtually any rotating  
machinery measurement.  
available. Exponentially averaged sound power (Leq) is  
calculated according to ANSI S1.4-1983, Type 0.  
Octave displays can be plotted as waterfalls with a fast 4 ms  
storage interval. Once data is stored in the waterfall buffer,  
the SR785 can display centile exceedance statistics for each  
1/1, 1/3 or 1/12 octave band as well as for Leq.  
Octave Analysis  
Real-time 1/1, 1/3, 1/12 octave analysis at frequencies up to  
40 kHz (single channel), or 20 kHz (2 channel) is a standard  
feature of the SR785. Octave analysis is fully compliant with  
ANSI S1.11-1986 (Order 3, type 1-D) and IEC 225-1966.  
Switchable analog A-weighting filters as well as A, B and C  
weighting math functions are included. Averaging choices  
include exponential time averaging, linear time averaging,  
peak hold and equal confidence averaging. Broadband sound  
level is measured and displayed as the last band in the octave  
graph. Total power, impulse, peak hold and Leq are all  
Swept-sine Bode plot of lowpass filter response. Top  
display shows magnitude with an expanded view of  
the passband response, while bottom display shows  
the phase response.  
Swept-Sine Measurements  
Network analysis using FFT mode produces fast results but  
suffers from limited dynamic range and frequency resolution.  
Swept-sine mode is ideal for network analysis that involves  
high dynamic range or wide frequency spans. Gain is  
optimized at each point in the measurement producing up to  
145 dB of dynamic range. A frequency resolution of up to  
2000 points is also provided. Auto-ranging can be used with  
source auto-leveling to maintain a constant input or output  
level at the device under test (to test response at a specific  
amplitude, for instance).  
Auto-resolution ensures the fastest possible sweeps and  
adjusts the frequency steps in the scan based on the DUT’s  
response. Phase and amplitude changes that exceed  
Expensive options are a thing of the past with the  
SR785. Real-time octave analysis is standard on  
every unit.  
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user-defined thresholds are measured with high frequency  
resolution, while small changes are measured using wider  
frequency steps between points. A choice of linear sweeps  
with high resolution, or logarithmic sweeps with up to eight  
decades of frequency range is provided.  
any portion of the signal can be played back in any of the  
SR785's measurement groups except swept-sine. The  
convenient Auto Pan feature lets you display measurement  
results synchronously with the corresponding portion of the  
capture buffer to identify important features.  
Unit Conversion  
Automatic unit conversion makes translating transducer data  
easy. Enter your transducer conversion directly in V/EU,  
EU/V or dB (1V/EU). The SR785 will display the result in  
units of meters, inches, m/sec2, in/sec2, m/s, in/s, mil, g, kg,  
lbs., N, dynes, pascals or bars. Built-in ICP® power means  
you don’t need an external power supply for your accelerome-  
ter. Acoustic measurement results can be displayed in dBSPL,  
while electrical units include V, V2, dBV and dBm.  
Source  
Top display shows a histogram of time data. Bottom  
display shows the cumulative density function.  
The SR785 comes standard with five precision source types.  
Generate low distortion (-80 dBc) single or two-tone sine  
waves, white noise, pink noise, chirps, and arbitrary  
waveforms. The chirp and noise sources can be bursted to  
provide activity over a selected portion of the time record for  
FFT measurements, or to provide impulse noise for acoustic  
measurements. The digitally synthesized source produces  
Time/ Histogram  
Use the time/histogram measurement group to analyze time  
domain data. A histogram of the time data vs. signal  
amplitude is provided for accurate time domain signal  
characterization. Statistical analysis capabilities include both  
probability density function (PDF) and cumulative density  
function (CDF). The sample rate, number of samples and  
number of bins can all be adjusted.  
Time Capture  
The SR785 comes with 2 Msamples of memory (8 Msamples  
optional). Analog waveforms can be captured at sampling  
rates of 262 kHz or any binary submultiple, allowing you to  
optimize sampling rate and storage for any application. For  
example, 8 Msamples of memory will capture 32 seconds of  
time domain data at the maximum 262 kHz sample rate, or  
about 9 hours of data at a 256 Hz sample rate. Once captured,  
Top display shows the burst noise source. Bottom  
display shows an arbitrary waveform downloaded to  
the SR785 via the IEEE-488 interface.  
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output levels from 0.1 mV to 5 V and offsets from 0 to ±5 V,  
and delivers up to 100 mA of current.  
Arbitrary waveform capability is standard with the SR785.  
Use the arbitrary source to playback a section of a captured  
waveform, play a selected FFT time record or upload your  
own custom waveform from your computer.  
User Math  
Create your own measurement in each of the SR785's  
measurement groups using the math menu. Enter any equation  
involving RMS averaged, vector averaged or unaveraged time  
or frequency data, stored files, constants, or a rich array of  
supplied operations including arithmetic functions, FFT,  
inverse FFT, jω, d/dω, exp, ln x, and many others. Because all  
the averaging modes are available as user math operands,  
non-repeatable runout measurements (used in analyzing disk  
drives) can be performed in a single pass by entering the  
equation MAG(RMS<F1>)-MAG(Vec<F1>). Unlike many  
other analyzers, the SR785's measurement rate is virtually  
unaffected when user math is selected. For instance, the  
function exp(ln(conj(FFT2/FFT1))) can be calculated with a  
100 kHz real-time bandwidth.  
Two 2k deep waterfall buffers ensure you’ll never  
miss important waterfall data.  
FFT, octave and order tracking measurements can be stored in  
the SR785's waterfall buffer memory. You can choose to save  
all measurements and averaging modes or just the current  
measurement to conserve memory. Waterfall traces can be  
stored every n time records for FFT and order tracking  
measurements. For order tracking measurements new records  
can be acquired at a specific time interval or change in RPM.  
In octave measurements, the storage interval is in seconds (as  
fast as every 4 ms). While displaying waterfall plots, you can  
adjust the skew angle to reveal important features, or change  
the baseline threshold to eliminate low-level clutter. Any  
z-axis slice or x-axis record can be saved to disk or displayed  
separately for analysis.  
Analysis  
The SR785 includes a wide variety of built-in analysis  
features. Marker analysis lets you easily measure the power  
contained in harmonics, sidebands or within a given band of  
frequencies. Important information such as THD, THD+N,  
sideband power relative to a carrier, or total integrated power  
are calculated in real-time and displayed on the screen. The  
front/back display feature allows you to display live data from  
both signal inputs on one graph. You can also simultaneously  
display saved traces and live data. The peak-find marker  
allows you to quickly locate frequency peaks with the click of  
a button. The marker statistics feature calculates the  
The SR785 doesn’t limit you to a few preselected  
measurements. With user math you can create an  
infinite variety of measurements.  
Waterfall  
maximum, minimum, mean and standard deviation of data in  
any section of the display. For modal analysis, the cursor can  
be configured to display the resonant frequency and damping  
of a single selected mode.  
Waterfall plots are a convenient way of viewing a time history  
of your data. Each successive measurement record is plotted  
along the z-axis making it easy to see trends in the data. All  
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Use data tables to display up to 100 selected data points in  
tabular format. Limit tables allow you to define up to 100  
upper and lower limit segments in each display for GO/NO  
GO testing. Data and limit table definitions can also be saved  
to and recalled from disk for quick setup.  
Synthesis reverses the process: enter a model in any of the  
above formats and the SR785 synthesizes the required curve.  
The curve fit/synthesis menu allows you to change gain, delay  
and frequency scale, set pole and zero locations and instantly  
see the response of the modeled system.  
Upper trace shows original frequency response  
data. Lower trace shows curve fit to a portion of the  
data.  
Output  
The SR785's built-in 3.5" 1.44 MB disk drive, GPIB and  
RS-232 computer interfaces and Centronics printer port  
combine to allow almost unlimited flexibility in saving,  
printing, plotting or exporting your measurement data.  
Displays and setups can be printed or plotted to disk, GPIB,  
RS-232 or Centronics port in PCX, GIF, PCL (LaserJet® and  
DeskJet®), dot-matrix, Postscript, HP-GL or ASCII formats.  
An annotation editor lets you add text, time and date, or  
filenames to any portion of the plot. For modal analysis  
applications, nodal degree-of-freedom information is stored  
with the data files to simplify transfer to external analysis  
programs.  
Curve Fit and Synthesis  
The SR785 has a standard 20-pole, 20-zero curve fitter that  
can fit frequency domain data from both the FFT and  
swept-sine measurement groups. Curve models can be  
displayed in pole/zero, pole/residue and polynomial formats.  
Data Conversion Utilities  
The SR785 contains a complete suite of data conversion  
utilities for both Windows® and DOS® operating systems.  
These versatile utilities make data transfer to and from  
external programs fast and simple. SR785 files can be  
converted to ASCII for use with spreadsheets, or Universal  
File Format (UFF) and HP SDF for use with modal analysis  
programs. SR785 Files can also be converted to MAT file  
format for use with MATLAB. Conversion from external file  
types is also supported. Both HP SDF and SR780 files can be  
converted to SR785 format.  
Enter frequency response models in pole/zero, poly-  
nomial, or pole/residue format.  
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Hypertext links let you quickly switch between related help  
pages or instantly reference the remote command correspond-  
ing to any function. Use the help index to quickly locate  
information on any topic, jump to the on-line troubleshooting  
guide, browse a complete listing of the SR785's specifica-  
tions, or examine a comprehensive description of the SR785's  
remote commands ... all from the front panel.  
Inside the SR785  
The computational heart of the SR785 is an Analog Devices'  
ADSP21020 32-bit floating point digital signal processor  
which delivers a true 102.4 kHz real-time bandwidth on both  
channels simultaneously – there's never a need to trade  
bandwidth for number of channels. Two precision 16-bit  
ADCs provide 90 dB dynamic range in FFT mode and 145 dB  
dynamic range in swept-sine mode – enough for the most  
demanding applications. With up to 800 lines of spectral  
resolution, the SR785 allows you to zoom in on any portion of  
the 476 mHz to 102.4 kHz range.  
The SRS DataViewer Windows utility enables you to  
view SR785 data files graphically and save them in  
different formats.  
DataViewer  
The SRS DataViewer is a Windows 95 program that allows  
you to quickly upload SR785 files into a graphical  
environment, perform simple editing and cut and paste into  
other applications. You can add pointers and text, change  
scaling, and perform simple math operations. Graphs can be  
saved in PCX, BMP or GIF formats.  
The Right Choice  
The SR785 Two Channel Dynamic Signal Analyzer offers  
more useful features and superior performance than  
competitive analyzers and is priced considerably lower. For  
more details on the SR785 and our other FFT analyzers, call  
Help  
Full, context sensitive help screens for all SR785 features  
means you will rarely have to refer to the user's manual.  
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Cross Channel  
±0.5 deg (dc to 51.2 kHz)  
±1.0 deg (dc to 102.4 kHz)  
(frequency response measurement, both  
inputs on the same input range, vector  
averaged)  
SR785 Specifications  
Specifications apply after 30 minutes of warm-up and within two  
hours of last auto-offset. All specifications are with 400 line FFT  
resolution and anti-alias filters enabled unless stated otherwise.  
Signal Inputs  
Measurement Groups  
Number of Inputs  
Full Scale Input Range  
2
Standard Groups  
FFT analysis, Correlation, Time  
Histogram, Swept Sine  
Order Tracking  
-50 dBV (3.16 mVpk) to +34 dBV  
(50 Vpk) in 2 dB steps  
57 Vpk  
Single-ended (A) or true differential  
(A-B)  
Optional Group  
Maximum Input Level  
Input Configuration  
Frequency  
Range  
102.4 kHz or 100 kHz (both displays  
have the same range).  
Input Impedance  
Shield to Chassis  
1 M+ 50 pF  
Floating mode: 1 M+ 0.01 mF  
Grounded mode: 50 Ω  
Shields are always grounded in  
differential input (A-B)  
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.  
100, 200, 400 or 800 lines  
FFT Resolution  
Maximum Shield Voltage 4 Vpk  
AC Coupling  
CMRR  
Real-Time Bandwidth  
102.4 kHz (highest FFT span with con-  
tinuous data acquisition and averaging).  
25 ppm from 20 ˚C to 40 ˚C  
-3 dB rolloff at 0.16 Hz  
90 dB at 1 kHz (in. range <0 dBV)  
80 dB at 1 kHz (in. range <10 dBV)  
50 dB at 1 kHz (in. range 10 dBV)  
Accuracy  
Dynamic Range  
Dynamic Range  
ICP Signal Conditioning Current Source: 4.8 mA  
Open Circuit Voltage: +26 V  
A-Weight Filter  
-90 dBfs typical, -80 dBfs guaranteed  
(FFT and Octave)  
Type 0 Tolerance, ANSI Standard  
S1.4-1983; 10 Hz to 25.6 kHz  
<-145 dB below signal (input to input  
and source to inputs, 50 receiving  
input source impedance)  
-145 dBfs typical (Swept-Sine)  
Includes spurs, harmonics, intermodu-  
lation distortion and alias products.  
Excludes alias responses at extremes of  
span.  
Crosstalk  
Input Noise  
<10 nVrms/Hz (<-160 dBVrms/Hz)  
above 200 Hz  
Harmonic Distortion  
Intermod. Distortion  
<-80 dB (single tone in band)  
<-80 dB (two tones in band, each  
less than -6.02 dBfs)  
Trigger Input  
Modes  
Spurious  
<-80 dBfs  
Free run, Internal, External, or External  
TTL  
Level adjustable to ±100% of input  
scale, positive or negative slope.  
Minimum Trigger Amplitude: 5% of  
input range  
Alias Responses  
<-80 dBfs (single tone outside of span,  
less than 0 dBfs, less than 1 MHz)  
100 dBfs typical (input grounded, input  
range >-30 dBV, Hanning window,  
64 RMS averages)  
Internal  
Full Span FFT Noise  
Floor  
Residual DC Response  
<-30 dBfs (FFT with Auto Cal on)  
External  
Level adjustable to ±5 V in 40 mV  
steps, positive or negative slope.  
Input impedance: 1 MΩ  
Amplitude Accuracy  
Single Channel  
Cross Channel  
±0.2 dB (excluding window effects)  
±0.05 dB (dc to 102.4 kHz)  
(frequency response measurement, both  
inputs on the same input range, RMS  
averaged)  
Max input: ±5 V  
Minimum trigger amplitude: 100 mV  
Requires TTL level to trigger  
(low <0.7 V, high >3.0 V)  
Measurement record is delayed up to  
100,000 samples after the trigger.  
Measurement record starts up to 8000  
samples prior to the trigger.  
External TTL  
Post-Trigger  
Pre-Trigger  
Phase Accuracy  
Single Channel  
±3.0 deg relative to External TTL  
trigger (-50 dBfs to 0 dBfs, freq  
<10.24 kHz, center of frequency bin,  
DC coupled). For Blackman-Harris,  
Hanning, Flattop and Kaiser windows,  
phase is relative to a cosine wave at the  
center of the time record. For Uniform,  
Force and Exponential windows, phase  
is relative to a cosine wave at the  
beginning of the time record.  
Tachometer Input  
Pulses Per Revolution  
RPM Accuracy  
Tach Level Range  
Tach Level Resolution  
Max. Tach Input Level  
1 to 2048  
±50 ppm (typical)  
±25 V, ±5V, TTL  
20 mV @ ±25 V, 4 mV @ ±5 V  
±40 Vpk  
Min. Tach Pulse Width 100 nSec  
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Flatness  
<0.25 dB pk-pk (typical),  
<1.0 dB pk-pk (max), 5000 rms  
averages  
Transient Capture  
Mode  
Continuous real-time data recording to  
memory.  
Maximum Rate  
Max. Capture Length  
262,144 samples/sec for both inputs  
2 Msamples (single input)  
8 Msamples with optional memory  
Pink Noise Source  
Bandwidth  
Flatness  
DC to 102.4 kHz  
<2.0 dB pk-pk, 20 Hz - 20 kHz  
(measured using averaged 1/3 octave  
analysis)  
Octave Analysis  
Standards  
Conforms to ANSI standard  
S1.11-1986, Order 3, Type 1-D.  
Band centers:  
Chirp Source  
Time Record  
Output  
Frequency Range  
Continuous or Burst  
Sine sweep across the FFT span  
±0.25 dB, 1.0 Vpk  
Single Channel  
1/1 Octave  
0.125 Hz - 32 kHz  
Flatness  
1/3 Octaves 0.100 Hz - 40 kHz  
1/12 Octaves 0.091 Hz - 12.34 kHz  
Two Channels  
Swept Sine Source  
Auto Functions  
Source level, input range and  
frequency resolution  
145 dB  
1/1 Octave  
0.125 Hz - 16 kHz  
1/3 Octaves 0.100 Hz - 20 kHz  
1/12 Octaves 0.091 Hz - 6.17 kHz  
<0.2 dB (one second stable average,  
single tone at band center)  
80 dB (1/3 octave, two second stable  
average) per ANSI S1.11-1986  
Impulse, Peak, Fast, Slow and Leq per  
IEC 651-1979 Type 0  
Dynamic Range  
Accuracy  
Arbitrary Source  
Amplitude Range  
Record Length  
±5 V  
Dynamic Range  
Sound Level  
2 Msamples (playback from arbitrary  
waveform memory or capture buffer).  
Variable output sample rate.  
General  
Order Tracking  
Monitor  
Monochrome CRT, 800H by 600V  
resolution, 8.2 inch diagonal display  
IEEE-488, RS-232 and Printer  
interfaces standard.  
All instrument functions can be  
controlled through the IEEE–488 and  
RS-232 interfaces. A PC (XT)  
keyboard input is provided for  
additional flexibility.  
Print to dot matrix and PCL  
compatible printers. Plot to HP-GL or  
Postscript plotters. Print/Plot to  
RS-232 or IEEE–488 interfaces or to  
disk file. Additional file formats  
include GIF, PCX and EPS.  
3.5" DOS compatible format, 1.44  
Mbytes capacity. Storage of displays,  
setups and hardcopy data.  
Power connector for SRS  
Resolution  
Amplitude Accuracy  
Displays  
Up to 400 lines  
±1 dB (typ.)  
Order map (mag and phase), order  
track (mag and phase), orbit  
Interfaces  
Curve Fit and Synthesis  
Type  
20-pole/20-zero non-iterative rational  
fraction fit.  
Pole-zero, polynomial, or pole-residue  
Output Format  
Hardcopy  
Source Output  
Amplitude Range  
Amplitude Resolution  
Offset Adjust  
0.1 mVpk to 5 Vpk  
0.1 mVpk  
±5 V  
Output Impedance  
<5 , ±100 mA peak output current  
Disk  
Sine-Source  
Amplitude Accuracy  
±1% of setting, 0 Hz to 102.4 kHz  
0.1 Vpk to 5.0 Vpk, high impedance  
load  
Preamp Power  
Power  
preamplifiers.  
70 Watts, 100/120/220/240 VAC,  
50/60 Hz  
17"W x 8.25"H x 24"D  
56 lbs.  
Harmonics, SubHarm.  
and Spurious Signals <-80 dBc (fundamental <30 kHz)  
<-75 dBc (fundamental <102 kHz)  
0.1 Vpk to 5 Vpk  
Dimensions  
Weight  
Warranty  
One year parts and labor on materials  
and workmanship.  
Two Tone Source  
Amplitude Accuracy  
±1% of setting, 0 Hz to 102.4 kHz,  
0.1 Vpk to 5 Vpk, high Z load  
<-80 dBc, 0.1 Vpk to 2.5 Vpk  
Harmonics, SubHarm.  
White Noise Source  
Time Record  
Continuous or Burst  
Bandwidth  
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Auto/Manual Arming, GPIB, RPM Step, Time Step, Pre/Post  
Trigger Delay  
SR785 Features  
Source Outputs  
Instrument Modes  
Sine, Two-Tone, Swept-Sine, White/Pink Noise, Burst Noise,  
Chirp, Burst Chirp, and Arbitrary  
FFT, Time/Histogram, Correlation, Octave, Swept-Sine, Order  
Tracking  
Windows  
Frequency Domain Measurements  
Hanning, Blackman-Harris, Flat Top, Kaiser, Force/Exponential,  
User-Defined, +/-T/2, +/-T/4, T/2, Uniform  
Frequency Response, Linear Spectrum, Cross Spectrum, Power  
Spectrum, Coherence, Power Spectral Density  
User Math  
Time Domain Measurements  
+, -, *, /, Conjugate, Magnitude/Phase, Real/Imaginary, Sqrt, FFT,  
Inverse FFT, jω, Log, Exp, d/dx, Group Delay, A, B, C  
Weighting, x/x-1, Trace 1 – 4, Vector Average, RMS Average,  
Peak Hold  
Time Record, Cross Correlation, Auto Correlation, Orbit  
Amplitude Domain Measurements  
Histogram, PDF, CDF  
Analysis  
FFT Resolution  
Harmonic, Band, Sideband, THD, THD + N, Limit Test with  
Pass/Fail, Data Table, Exceedance, Statistics, Curve Fit and  
Synthesis  
100, 200, 400, 800 lines  
Views  
Linear Magnitude, Log Magnitude, dB Magnitude, Magnitude  
Squared, Real Part, Imaginary Part, Phase, Unwrapped Phase,  
Nichols, Nyquist, Polar  
Time Capture  
Capture Time Data for later analysis (FFT or Octave). Up to 2  
Msamples (8 Msamples optional) of data can be saved.  
Units  
Storage  
V, V2, V2/Hz, V/Hz, meters, meters/sec, meters/sec2, inches,  
inches/sec, inches/sec2, mils, g, kg, lbs., N, dynes, pascals, bars,  
SPL, user-defined engineering units (EUs)  
3.5”, 1.44 Mbyte, DOS formatted disk. Save data, setups and hard  
copy data.  
Hard Copy and Interfaces  
Displays  
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) or to disk file. EPS, GIF, PCX  
graphic formats also available for disk storage.  
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  
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.  
Averaging  
RMS, Vector, Peak Hold, Linear, Exponential, Equal Confidence  
(Octave), Preview Time Record, % Overlap Averaging, Overload  
Reject  
DataViewer  
Windows 95 based graphics program for viewing SR785 files.  
Graphs can be pasted to the clipboard or saved in PCX, BMP or  
GIF formats.  
Triggering  
Continuous, Internal, External (Analog or TTL), Source,  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Ordering Information  
(All prices U.S. list)  
SR785  
Two Channel Dynamic Signal Analyzer . . . $11,950  
(includes manual, DataViewer,  
disk utilities and power cord)  
Option O785OT  
Option O780RM  
Option O780M1  
Option O78012V  
CT100  
Order Tracking . . . . . . . . . . . . . . . . . . . . . . . Free (introductory offer)  
Rack Mount Kit. . . . . . . . . . . . . . . . . . . . . . . $85  
8 Msample RAM. . . . . . . . . . . . . . . . . . . . . . call for pricing  
12 VDC-115 VAC Converter. . . . . . . . . . . . . $295  
MobileCart . . . . . . . . . . . . . . . . . . . . . . . . . . $495  
12 VDC Converter  
Designed to power the SR785 in the field when AC power is not available.  
Specifications  
Input Voltage  
10 VDC to 15 VDC  
115 VAC true RMS 5%  
200 W  
300 W  
0.34 A  
Output Voltage  
Max Cont. Output Power  
Max Peak Output Power  
Input No Load Current  
MobileCART  
The SRS CT100 MobileCART makes the SR785 truly portable. Its rugged  
construction and full rack capacity will free up your valuable work space  
and allow you to take the SR785 wherever you need to go.  
Specifications  
Tray Size  
17" x 22" (tray accommodates one  
full width rack mount instrument)  
Maximum Tray Load  
Maximum Base Load  
Angular Adjustment  
Weight  
60 lbs.  
100 lbs.  
Horizontal to 60¼  
58 lbs.  
STANFORD RESEARCH SYSTEMS  
SRS  
1290 D Reamwood Avenue ¥ Sunnyvale, CA 94089  
Telephone (408)744-9040 ¥ FAX: (408)744-9049  
Printed in USA ©1998 Stanford Research Systems, Inc. All specifications and prices subject to change (1/98)  
All trademarks are the property of their respective owners.  
Download from Www.Somanuals.com. All Manuals Search And Download.  

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