Audio, Audio …… 13-6 – Measurement Computing DataShuttle User Manual
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13-6 Analog Input & Output
11-12-01
DataShuttle and DynaRes
Figure 13-3c shows an amplified piezoelectric sensor configuration. Many piezoelectric sensors provide
only a few millivolts of signal, so they need a preamplifier. The power for this preamplifier can be taken
directly from the power supply terminals on your terminal panel. The output of the preamplifier can then
be read directly with your data acquisition board as shown in Figure 13-3c.
Figure 13-3. Piezoelectric Sensor Configurations
Audio
Figure 13-4a shows a simple DC-coupled audio configuration. In this configuration, an audio source is
connected to the terminal panel, using either coaxial cable or twisted pair cable. R3 is the termination
resistor, which is used to terminate the audio signal. In many cases, the termination resistor is not needed.
In some cases, the termination resistor is the characteristic impedance of the cable, often 50, 75, or 150
ohms. Refer to the technical manual of your audio transducer or microphone for the selection of the
termination resistor.
Figure 13-4b shows an AC-coupled audio example, which is the most common implementation. AC-
coupled audio is easier to measure because any DC offset in the audio signal is automatically removed for
you.