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adc_capture type of data saved

Question asked by foukalas@gmail.com on May 26, 2016
Latest reply on Jun 1, 2016 by DragosB

Hi,

we have done an LTE Tx waveform transmission using the no-OS example with some modifications. We use a Matlab produced waveform that is a column of real data (153600 number of samples) with positive and negative values. The correct LTE Tx is confirmed from the figure attached Tx_NoOS.jpeg.

We use the adc_capture and the procedure to get the sample_I1 and sample_Q1 used also for the generic example of sine wave transmission found here: no-OS/ad9361/sw at master · analogdevicesinc/no-OS · GitHub.. and the capture.bat script file.

The question is why we receive data (the attached rx.csv file) that are not depicting an LTE waveform when we plot with for example the dsp.spectrumanalyzer of Matlab. On the other hand, there is no any negative value in the cvs value and this raises a question about the interpretation of the data.

Therefore, the question is what type of data we should expect in the cvs file? The same happens also for this example here: no-OS/ad9361/sw at master · analogdevicesinc/no-OS · GitHub  that we need to make them floating point in order to get the sine wave at the receiver side.

 

Please advice us about this, i.e. what type of data the adc_capture saves to the register and what type of interpretation we need to provide in order to see our waveform correctly.

 

Unless, the reception is not accomplished correctly.

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