dSPACE CLP1104, Hardware Installation And Configuration

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Signal Connection to External Devices
DS1104 Hardware Installation and Configuration March 2004
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Measuring Noise
It is often claimed that the noisy signal measured with the dSPACE
board looks much better when measured with an oscilloscope. The
reason is that you are using the wrong “voltage range” for the
dSPACE system!
dSPACE boards have an input range of ±10 V and you are looking at
signals with a voltage range of a few mV. That is similar to using a ruler
to measure 1/1,000 inches. When you use your oscilloscope, you
select an appropriate voltage range for the signal you are watching.
You should do the same with the dSPACE system: You should adapt
your input signal to the ±10 V scale of the dSPACE board before
converting it. Use external amplifiers to ensure that the maximum
amplitude range of the signal to be measured is mapped to the full
scale range of the ADC, which is usually ±10 V.