IF RIO 5640R Analog Output

[sidda]

Hi,
I am using IF RIO 5640R board. In this I want to write a some numerical value on to the DAC and I want to see the analog output of the corresponding value. Please help me.

[JerryAL]

Hi Sidda

I’m not sure that you understand how the NI 5640R module works.  The DACs on the module use Digital Up Conversion and you just can’t write a sample to the DAC and see a corresponding voltage level at the output.

I suggest that you read the Analog Output section of the NI 5640R Help file.

Also, here are some other links that talk about I/Q data.

What is I/Q Data?
http://zone.ni.com/devzone/cda/tut/p/id/4805

Sources of Error in IQ Based RF Signal Generation
http://zone.ni.com/devzone/cda/tut/p/id/5657

I hope this helps.
Jerry

[sidda]

Thank you Jerry,
I am using IF RIO 5640R.  With this  i want to do  FM Demodulation. I am giving 70MHz IF with 20MHz Baseband signal at the AIO input. Presently I acquired the adc output  i.e I and Q.    My question is
1) What is the frequency of I and Q data.
2) The base band signal will appear on i and q.
3) The ADC output will have carrier signal or not.

Please help me on these questions


Siddu

[JerryAL]

Hi Siddu

1. That depends on the IQ rate that you selected.  Normally the ADC is running at 100 MSps.  A decimation setting of 128 will have a IQ rate of ~781 KHz.  And a bandwidth of about 781 KHz x 0.8 = 625 KHz.  The 0.8 factor depends on filters, etc, but 0.8 is pretty close.  The frequency range of the data is basically -325 KHz to +325 KHz.
2. Yes
3. No carrier, RF or IF.  Baseband information only.

Jerry