Communication between NI Speedy and NI Single Board RIO

[Eric LUO]

I plan to using a NI speedy board to generating a continuous sinusoidal sigal with specifed frequency and received by the NI Single Board RIO on a point by point basis. I'm using a headphone cable wiring the audio output of the speedy board to AI0(DIFF mode, +-1V) and GND of NI Single Board RIO. The specification of the audio output of speedy board says that the max working voltage for analog outputs(signal + common mode) is 1.41V. I don't know if there's a kind of relationship between the amplitude of the signal wired to the output I/O terminal on the block diagram and the physical output signal. According to my observation, the received signal is pulled up a little bit. Is there a way to remove completely the DC component?

Another issue is that I'm expecting a sampling rate of 8kHZ for the RIO board, but it seems that the RT system can only samples at around 2kHz at most. Is there any way to make it working.

The project file is attached as follows,

Thank you for your help.

[Burt_S]

I am not very familiar with the NI Speedy-33, but I should be able to help with the sampling issue you are having.  Right now your sampling rate is limited by the speed of the RT acquisition loop.  To get around this, you should send your data in larger chunks using a DMA FIFO.  With this method, your limiting factor will become the speed of the ADC.  Take a look at this for an example of using a DMA FIFO.