Measurement Computing Data Translation DT3034, User Manual

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Using Your Own Screw Terminal Panel
165
Analog Outputs
Most data acquisition boards have a minimum of two analog output channels, with a
resolution of 12 to 16 bits (even though the accuracy may be less).
On all Data Translation boards, we ensure that the analog outputs do not break into a high
frequency oscillation with high capacitance loads that may be experienced with long cables.
Typically, the analog outputs drive 1,000 pF without degradation and bandwidth-limit with
higher capacitive loads.
The grounds of most boards are optimized for analog inputs at the expense of some logic or
high-frequency noise on the analog outputs. This is because the analog and digital grounds of
the board are connected at the ADC’s input.
The analog outputs are brought out as a high and a low signal, but the low side is the analog
ground at the DAC’s output buffer. To remove the high-frequency noise and smooth the
glitch energy on the analog outputs, you can install a 15 kHz RC filter on the output, a 100

resistor in series with the output, and a 0.1

F capacitor between the output side of the 100

resistor and output low.