Atec Stanford-Research-Systems-SR785 - Manual (Page 3)

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 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.
Time/Histogram
The time/histogram measurement group is used 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 8 Mbytes of memory (32 Mbytes
optional). Analog waveforms can be captured at sampling
rates of 262 kHz or any binary sub-multiple, 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,
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.
Transducer Units
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/sec 2 , in/sec 2 , m/s, in/s, mil, g, kg,
lbs., N, dynes, pascals or bars. Built-in ICP power is provided
for accelerometers. Acoustic measurement results can be
displayed in dBSPL, while electrical units include V, V
2 , dBV
and dBm.
Source
The SR785 comes with six precision source types: low-
distortion (
− 80 dBc) single or two-tone sine waves, white
noise, pink noise, chirp, 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 output levels from
0.1 mV to 5 V, DC offset 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
Custom measurements can be created in each of the SR785's
measurement groups using the math menu. Enter any equation
involving rms averaged, vector averaged or unaveraged time
SR785 Dynamic Signal Analyzer
Stanford Research Systems phone: (408)744-9040
www.thinkSRS.com
Swept-sine Bode plot of low pass filter response
User Math
Burst noise source (top), arbitrary waveform source (bottom)