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NI-9264 Question

I am using one channel of a NI-9264 to drive a laser modulation voltage. Given this DAC will swing +-10 volts with 16 bits of precision, I should have a resolution of about 300 microvolts. I can see this resolution on a scope, but I also see about +- 2 millivolts of noise.

 

I am using a BNC ended coax cable to connect the 9264 to the scope, but there is a short section of wire coming out of the 9264 terminal block to a female BNC. Does anyone have a suggestion how best to determine if this +- 2 millivolts of noise is real or a product of me measuring such low voltages.

 

Thanks,

 

Steve

 

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Hello sbailey64,

 

There are several sources of noise e.g the environment and also the scope itself. To eliminate possible causes, I would recommend testing a different signal source other than the DAC e.g a function generator? If noise is still observed then the issue may be stemming from noise introduced by the scope. Additionally, you can also verify the DAC signal using a hand held DMM. If these results are consistent with your initial observations then there could be a possible issue with the DAC. However, before you narrow down to a hard conclusion, dont forget to investigate the wiring (check if tightly secured/try a different cable) and the application environment e.g lights, electronic devices etc.

 

Best regards,

 

Ali M

Applications Engineer

National Instruments

www.ni.com/support

 

 

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