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What is the bbFetchRaw data buffer format while using the BB_STREAM_IF flag?

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  • August 3, 2015 at 7:32 pm #51265
    guoan
    Participant

    Hi,
    I would like to get the direct IF digital samples and save them into a binary file using BB60C. If I set the flag bb_STREAM_IF flag when calling bbInitiate(), what’s the format of the data stream buffer which obtained by calling bbFetchRaw().

    Best Regards.
    guoan

    • This topic was modified 11 years, 2 months ago by guoan.
    • This topic was modified 11 years, 2 months ago by guoan.
    August 4, 2015 at 8:41 am #51374
    AndrewAndrew
    Moderator

    Hello Guoan,

    If you use the BB_STREAM_IF flag, the data format is 80MS/s 16bit IF samples. This is the raw data format used internally in the API to create the I/Q data. The samples are full scale and un-calibrated. The center frequency you select should be a multiple of 400kHz. In the frequency domain the IF passband will be centered between 0 Hz and the Nyquist frequency (0.5*fs). The timebase error is not accounted for so frequency will not be exact. Decimation and bandwidth do not apply, it is always 27MHz bandwidth and 80MS/s for the BB60C.

    The only benefit to this is that in this mode, the CPU load is very low, since almost no processing is performed on the data, it is simply handed off straight from the device.

    Regards,
    A.J.

    • This reply was modified 11 years, 2 months ago by AndrewAndrew.
    August 4, 2015 at 6:02 pm #51456
    guoan
    Participant

    Thanks a lot for your valuable information, Andrew.

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