Open Transducer Detection/Overload Conditions - VTI Instruments EX1401 User Manual

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CLK=32*2^n*fs
PLL
It is possible to specify the sampling rate two ways. In the first method you can specify each
parameter of the data decimation chain; including ADC sample clock frequency, filter type and
configuration, downsampling factor etc., to produce a required data output rate. In the second
method you may simply specify the final data sample rate (or the frequency span of interest), and
desired filter type, such that all other dependent parameters will be automatically adjusted, to
produce output at desired sample rate.
The noise floor performance of the system also depends heavily on the decimation rate, since higher
decimation factors will help improve the signal-to-noise ratio. Given below are typical noise level
performance specifications at various input voltage ranges.
Voltage Range
±100mV
±100mV
±100mV
±100mV
±100mV
±1V
±1V
±1V
±1V
±1V
±10V
±10V
±10V
±10V
±10V
T 3-2: V
ABLE OLTAGE
O T D
PEN RANSDUCER ETECTION
The EX1401 provides the ability to detect several different signal overload conditions, as well as
several ways to report them. They are reported on a per-channel basis as a 32-bit mask of active
conditions, via the Channel.Overload.Status property. The following bits are supported for the
EX1401:
Bit Mask
40
Raw | (Filter = None)
2^n*fs
High Performance
CIC
(/4 to /8192)
F 3-1: ADC
IGURE AND
Full Scale V Decimation
in
factor
100mV 1
100mV 10
100mV 100
100mV 1000
100mV 10000
1V 1
1V 10
1V 100
1V 1000
1V 10000
10V 1
10V 10
10V 100
10V 1000
10V 10000
M N P
EASUREMENT OISE
/O C
VERLOAD ONDITIONS
Name
Decimate 2^n
FIR
Downsampling
(Customizable)
(/1 to /65536)
(n=1 to 16)
Low Latency
CFIR
Medium Latency (/4)
Customizable
F S
ILTER CHEME
V (uVpp) S/N Ratio (dB)
Noise
65.3 dB
16.20
5.12 75.3 dB
1.62 85.3 dB
95.3 dB
0.51
105.3 dB
0.16
77.4 dB
65.00
87.4 dB
20.55
103.4 dB
6.50
107.4 dB
2.06
117.4 dB
0.65
75.6 dB
966.00
85.6 dB
305.48
95.6 dB
96.60
105.6 dB
30.55
115.6 dB
9.66
V . D (S
ROFILE S ECIMATION
Description
Blind Gain/Offset/
Engineering
Unit Conversion
)
AMPLING RATE
EX1401 Basic Operation