Weird return value discrepancies between Softshell and RTL-SDR


I’ve made significant progress porting over the rtl-sdr code.  I added printfs to every function that interfaces with the USB port so that I can compare what happens.  Everything seems normal, up until the gainControl function.  Once there, the returns from my application are usually about one digit off of the rtl-sdr code.  If anyone has any ideas, I’d love to hear them!

Link to the comparison spreadsheet.

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  1. #1 by Lars on May 11, 2012 - 1:00 am

    Nice work! About the gainControl, I believe the rtl-srd code added a new E4000 driver about a week ago that disabled the automatic gain control in the old driver. Did you maybe port the old one and compare it now with the new one?

  2. #2 by hpux735 on May 11, 2012 - 6:03 am

    I finished the E4000 port the day before the new e4k implementation was released! Kinda frustrating, but the new version seems to be a lot better. I was comparing apples to apples, which is what’s so strange. The spreadsheet shows that the values I’ve been sending the rtl are identical to the reference, but a few return values are reliably different. I have plans to update to the new version, but as it works currently, I’ve got a few other things on my to-do list first.

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