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Dynamic Signal Analyzer  SR780 ... from $9950 
SR780 — 100 kHz 2ch. FFT analyzer 
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SR780 Dynamic Signal Analyzer

The SR780 Dynamic Signal Analyzer combines high performance and low cost in a fullfeatured package. It offers 102.4 kHz dualchannel FFTs with 90 dB dynamic range, sweptsine measurements, ANSI standard octave analysis, waterfall displays and transient capture for less than half the cost of other similarly equipped analyzers. 
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SR780 Dynamic Signal Analyzer
The SR780 Dynamic Signal Analyzer combines high performance and low cost in a fullfeatured package. It offers 102.4 kHz dualchannel FFTs with 90 dB dynamic range, sweptsine measurements, ANSI standard octave analysis, waterfall displays and transient capture for less than half the cost of other similarly equipped analyzers.
Spectrum Analysis
The SR780 delivers true twochannel, 102.4 kHz FFT performance. Its fast 32bit floatingpoint DSP processor gives the SR780 a 102.4 kHz realtime rate with both channels selected. Two precision 16bit ADCs provide a 90 dB dynamic range in FFT mode. Selectable 100 to 800 line analysis optimizes time and frequency resolution, and you can zoom in on any portion of the 102.4 kHz range with a frequency span down to 191 mHz.
The SR780’s unique architecture lets the two displays function independently. You can choose separate frequency spans, starting frequencies, number of FFT lines, or averaging modes for each display. So it’s easy look at a wideband display and zoom in on a specific feature simultaneously. The SR780 lets you select from two sampling rates: 256 kHz or 262 kHz, so frequency spans come out in either a binary (102.4 kHz, 51.2 kHz,...) or decimal (100 kHz, 50 kHz, 25 kHz,...) sequence depending on your requirements.
Flexible Averaging
Several averaging choices are provided. RMS averaging reduces signal fluctuations, while vector averaging minimizes noise from synchronous signals. You can choose linear averaging (stable averaging) for fixed signals, or exponential averaging to track drifting features. Because the SR780’s 102.4 kHz realtime bandwidth lets it take data seamlessly, vector averaging can be selected for any signal that’s repetitive within the time record—no trigger is necessary.
Transducer Units
Automatic unit conversion makes translating accelerometer data easy. You can enter accelerometer conversions directly in V/EU, EU/V or dB (1 V/EU). The SR780 will display results in units of meters, inches, mil, g, kg, lbs., N, dynes, pascals, bars, or dBSPL. Accelerometer data is automatically converted to velocity or displacement units. Builtin ICP power means you won’t need an external power supply for your accelerometer.
Octave Analysis
Realtime octave analysis at frequencies up to 40 kHz (single channel) or 20 kHz (twochannel), is standard in the SR780. Octave analysis is fully compliant with ANSI and IEC standards. Full octave, 1/3 octave and 1/12 octave analysis are all available. Switchable analog Aweighting filters as well as builtin user math weighting functions (A,B and C) are included. Octave averaging choices include exponential time averaging, linear time averaging, peak hold, and equal confidence averaging. IEC compliant peak hold, impulse, fast and slow sound level measurements are all calculated.
SweptSine Analysis
Sweptsine analysis is used for measurements involving high dynamic range or wide frequency intervals, and is also a standard feature of the SR780. Selectable autoranging optimizes the input range at each point in the measurement, providing up to 145 dB of dynamic range. Autoranging can be used with source autoleveling to maintain a constant input or output level at the device under test. To ensure the fastest sweeps possible, autoresolution can also be selected, providing a variable scan speed tailored precisely to the signal being measured.
User Math
Userdefined math functions are available in all measurement groups. Equations are created from time or frequency data, stored files, constants, or a rich array of supplied operations including the arithmetic functions, FFT, inverse FFT, jΩ, d/dΩ, exp, ln x and many others. Unlike many analyzers, the SR780's measurement rate isn't reduced when user math is selected. For instance, the function exp(ln(conj(Average(FFT2/FFT1))) can be calculated with a 50 kHz realtime bandwidth.
Source
Six source types are available: low distortion (80 dBc) single or twotone sine waves, chirp, white noise, pink noise, and arbitrary waveforms. The chirp and noise sources can both be bursted to provide a source that’s active only over a selected portion of the time record for FFT measurements, or to provide an impulsive noise source for acoustic measurements. The digitally synthesized source provides output levels from 0.1 mV to 5 V, and delivers up to 100 mA of current.
Arbitrary waveform capability is standard on the SR780. The arbitrary source can be used to playback a section of a captured waveform, play a selected FFT time record or upload a custom waveform.
Capture
The SR780 comes standard with 2 Msamples of standard capture memory. Waveforms can be captured at 262 kHz or any submultiple of 262 kHz, allowing you to select the sample rate and capture length that’s right for your data. Once captured, any portion of the signal can be played back in FFT or Octave mode. The convenient AutoPan feature lets you display the measurement results synchronously with the corresponding portion of the capture buffer to easily identify important features. An optional memory expansion module lets you extend the SR780’s capture depth to 8 Msamples—that’s almost 30 seconds of capture at the maximum sampling rate.
Waterfall
All Octave and FFT Measurements can be stored in the SR780’s 2kdeep waterfall buffers. Waterfall storage is selectable as every n^{th} time record for FFT measurements, or you can select a storage interval in seconds (down to 4 ms) for octave measurements. While displaying waterfalls, you can adjust the skew angle to reveal important features, or change the baseline threshold to eliminate lowlevel clutter. Any zaxis slice or xaxis record can be saved to disk or displayed separately for individual analysis.
Analysis
The SR780 includes a wide variety of builtin analysis features. Marker analysis lets you use the marker to easily measure the power contained in the harmonics, sidebands, or within a given band of frequencies. THD, THD+N, sideband power relative to carrier, and total integrated power are calculated in real time and displayed on the screen. Marker statistics quickly calculate the maximum, minimum, mean and standard deviation of data at any point in the display.
A data table feature lets you 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/NOGO testing.
Output
The SR780's builtin USB drive, computer interfaces (GPIB and RS232) and printer port provide flexibility when saving, printing and exporting data. Data can be saved in binary or ASCII formats and displays can be printed/plotted to any of the ports or the disk drive. Supported formats include PCL, GIF, PCL (LaserJet/ DeskJet), dotmatrix, postscript and HPGL, PCX or GIF. Utilities are included to translate your HP SDF files into SR780 format.
Measurements  FFT Group
FFT, Time Record, Windowed Time, Time Capture,
Transfer Function, Cross Spectrum, Coherence, CrossCorrelation,
AutoCorrelation, Orbit, User Math
Measurements  Octave Analysis Group
1/1, 1/3, 1/12 Octave, Time Capture, User Math, L_{eq},
Impulse, Total Power
Measurements  SweptSine Group
Spectrum, Transfer Function, Cross Spectrum, User Math
FFT Resolution
100, 200, 400, 800 lines
Views
Linear Magnitude, Log Magnitude, Magnitude Squared, Real Part, Imaginary
Part, Phase, Unwrapped Phase, Nichols, Nyquist
Units
V, V^{2}, V^{2}/Hz,
V/√Hz, meters, inches, mils, g, kg, lbs., N, dynes, pascals,
bars, SPL, userdefined engineering units (EUs)
Displays
Single, Dual, Waterfall with Skew, Zoom and Pan
Averaging
RMS, Vector, Peak Hold, Linear, Exponential, Equal Confidence (Octave),
Preview Time Record
Triggering
Continuous, Internal, External (Analog or TTL), Source, Auto/Manual
Arming
Source Outputs
Sine, TwoTone, SweptSine, White/Pink Noise, Burst Noise, Chirp,
Burst Chirp, and Arbitrary
Windows
Hanning, BlackmanHarris, FlatTop, Kaiser, Force/Exponential, UserDefined,
+/T/2, +/T/4, T/2, Uniform
User Math
+, , ×, /, Conjugate, Magnitude/Phase, Real/Imaginary, Sqrt,
FFT, Inverse FFT, jΩ, Log, Exp, d/dx, Group Delay,
A, B, CWeighting, x/x1
Analysis
Harmonic, Band, Sideband, THD, THD + N, Limit Test with Pass/Fail,
Data Table, Exceedance, Statistics
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 and setups.
Hard Copy and Interfaces
Print to dot matrix or PCL (LaserJet and DeskJet) printers. Plot
to HPGL or postscript plotters. Print/plot online (RS232 serial,
Centronics parallel or IEEE488.2) or to disk file. EPS, GIF, PCX
graphic formats also available for disk storage.
SR780 Dynamic Signal Analyzer  
Specifications apply after 30 minutes warmup and within 2 hours of last autooffset. Measured with 400 line resolution and antialias filters enabled unless stated otherwise.  
Measurement Groups  
Groups  FFT, Octave Analysis, SweptSine 
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 
Realtime bandwidth  102.4 kHz (highest FFT span with continuous data acquisition and averaging) 
Accuracy  25 ppm from 20 °C to 40 °C 
Dynamic Range  
Dynamic range  
FFT and Octave SweptSine 
90 dB typical, 80 dB guaranteed. 145 dB Includes spurs, harmonic and intermodulation distortion and alias products. Excludes alias responses at extremes of span. 
Harmonic distortion  <80 dB (single tone in band) 
Intermod. distortion  <80 dB (two tones in band, each less than 6.02 dBfs) 
Spurious  <80 dBfs 
Alias responses  <80 dBfs (single tone outside of span, <0 dBfs, less than 1 MHz) 
Fullspan FFT noise floor  100 dBfs typ. (input grounded, >30 dBV, Hanning window, 64 rms averages) 
Residual DC response  <30 dBfs (FFT with AutoCal on) 
Amplitude Accuracy  
Single channel  ±0.2 dB (excluding windowing) 
Cross channel  ±0.05 dB (DC to 102.4 kHz) (transfer function 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, frequency <10.24 kHz, center of frequency bin, DC coupled). For BlackmanHarris, 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. 
Cross channel  ±0.5 deg. (DC to 51.2 kHz) ±1.0 deg. (DC to 102.4 kHz) (transfer function measurement, both inputs on the same input range, vector averaged) 
Signal Inputs  
Number of inputs  2 
Fullscale input range  50 dBV (3.16 mVp) to +34 dBV (50 Vp) in 2 dB steps 
Maximum input level  57 Vp 
Input configuration  Singleended (A) or differential (AB) 
Input impedance  1 MΩ + 50 pF 
Shield to chassis  Floating mode: 1 MΩ + 0.01 µF. Grounded mode: 50 Ω. Shields grounded in (AB) mode 
Max. shield voltage  4 Vp 
AC coupling  0.16 Hz cutoff frequency 
CMRR  90 dB at 1 kHz (input range <0 dBV) 80 dB at 1 kHz (input range <10 dBV) 50 dB at 1 kHz (input range ≥10 dBV) 
ICP signal conditioning  Current source: 4.8 mA Open circuit voltage: +26 V 
Aweight filter  Type 0 tolerance, ANSI standard S1.41983 (10 Hz to 25.6 kHz) 
Crosstalk  <145 dB below signal (input to input and source to inputs, 50 Ω receiving input source impedance) 
Input noise  <10 nVrms/√Hz above 200 Hz (<160 dBVrms/√Hz) 
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 MΩ Max. input: ±5 V Min. trigger amplitude: 100 mV 
External TTL  Requires TTL level to trigger (low <0.7 V, high >3.0 V) 
Posttrigger  Measurement record is delayed up to 8192 samples after the trigger. 
Pretrigger  Measurement record starts up to 8192 samples prior to the trigger. 
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 1D and IEC 2251966 
Frequency range  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  <0.2 dB (1 second stable average, single tone at band center) 
Dynamic range  80 dB (1/3 Octave, 2 second stable average) per ANSI S1.111986 
Sound level  Impulse, Peak, Fast, Slow and L_{eq} per ANSI S1.41983 Type 0 and IEC 6511979 Type 0 
Source Output  
Amplitude range  0.1 mVp to 5 Vp 
Amplitude resolution  0.1 mVp (output >500 mVp) 
DC offset  <10.0 mV (typ.) 
Offset adjust  ±5 VDC (sine, twotone) 
Output impedance  <5 Ω, ±100 mA peak output current 
Sine Source  
Amplitude accuracy  ±1 % of setting, 0 Hz to 102.4 kHz 0.1 Vp to 5.0 Vp, HighZ load 
Harmonics, subharm. & spurious  0.1 Vp to 5 Vp <80 dBc (fundamental <30 kHz) <75 dBc (fundamental <102 kHz) 
TwoTone Source  
Amplitude accuracy  ±1 % of setting, 0 Hz to 102.4 kHz 0.1 Vp to 5 Vp, HighZ load 
Harmonics, subharm.  <80 dBc, 0.1 Vp to 2.5 Vp 
White Noise Source  
Time record  Continuous or burst 
Bandwidth  DC to 102.4 kHz or limited to span 
Flatness  <0.25 dBpp (typ.), <1.0 dBpp (max.), 5000 rms averages 
Pink Noise Source  
Bandwidth  DC to 102.4 kHz 
Flatness  <2.0 dBpp, 20 Hz to 20 kHz (using averaged 1/3 Octave Analysis) 
Chirp Source  
Time record  Continuous or Burst 
Output  Sine sweep across the FFT span 
Flatness  ±0.25 dB (amplitude: 1.0 Vp) 
SweptSine Source  
Auto functions  Source level, input range and frequency resolution 
Dynamic range  145 dB 
Arbitrary Source  
Amplitude range  ±5 V 
Record length  2 Msamples (playback from arbitrary waveform memory or capture buffer). Variable output sample rate. 
General  
CRT monitor  Monochrome, 800H by 600V resolution 
Interfaces  IEEE488.2, RS232 and printer interfaces standard. All instrument functions can be controlled through computer interfaces. A PC (XT) keyboard input is provided for additional flexibility. 
Hardcopy  Print to dot matrix and PCL compatible printers. Plot to HPGL or postscript plotters. Print/plot to RS232 or IEEE488.2 interfaces or to disk file. Additional file formats include GIF, PCX and EPS. 
Data storage  USB drive 
Preamp power  Power connector for SRS preamps 
Power  70 W, 100/120/220/240 VAC, 50/60 Hz 
Dimensions  17" × 8.25" × 24" (WHL) 
Weight  56 lbs. 
Warranty  One year parts and labor on defects in materials and workmanship 