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audio testing with a DAQ 6020E

I have the standard 6.X SW and the 6020E hardware and am pretty new to LV. I need to analyze speaker receivers and microphones. Is this adequate or should I be using something more appropriate?
Example VI's with this hardware are welcomed.
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One of the big problems you will be faced with using the NI 6020E is the ability to take phase measurements through simultaneously sampling its analog inputs. The architecture of most E-series boards is such that you have a multiplexer in front of the ADC, allowing multiple channels to be sampled. The result of acquiring signals across multiple channels is that the multiplexer must select each signal in turn. This will take a finite period of time and and as such will introduce phase errors into the signals that you capture. This is not a big problem if it is only a single channel that you acquiring but I would expect that you are likely to want to sample 2 channels (stereo) perhaps even more.

In an ideal world, you would have the same number of ADCs for the number of channels you need to acquire on. There are specific data acquisition products from NI that are more aimed as audio acquisition/analysis. Perhaps consider the NI 447x range of dynamic signal analyzers - further details are on ni.com including user manuals. They also will have benefits in terms of increased dynamic range (they use 24-bit ADCs as opposed to the 12-bit converters on your NI 6020E).

However to maximize the use of the board that you have, you could consider an external sample and hold board such as the SC-2040. This will allow you to take simultaneous samples across up to 8 channels. There are calculations that need to done in order to work out the maximum sample rate available for your board - see SC-2040 user manual for details - but it might prove a more cost effective solution.

From a software point of view, setting up a data acquisition application should be straightforward as there are a number of example showing the different acquisition methods (one-shot, triggered, continuous etc.). As for examples of analysis routines, that will depend entirely on the analysis you wish to perform. The LabVIEW Base package has a very limited set of analysis functions and will not be suitable for the type of work you are likely to be undertaking.

LabVIEW FDS has a good range of frequency analysis tools - these can be supplemented with the Sound & Vibration toolkit which adds more specific audio analysis functions to LabVIEW - whether this is suitable for you will depend on the type of analysis you wish to perform.

Jeremy
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