Pluto SDR Gnu radio companion Carrier Over shhot problem?

When Pluto starts and performs certain changes it will calibrate itself. This will generate tones that come out the transmit port. That is likely what you are observing.

-Travis

Thanks for the reply. how can we disable that calibration in PlutoSDR. because it is damaging my power amplifier. 

You need to set calib_mode to manual: https://wiki.analog.com/resources/tools-software/linux-drivers/iio-transceiver/ad9361#calibration_mode_controls

This can be done with the Attribute sink block . This only needs to be done once.

-Travis

Hi Travis,

If I am not using PlutoSDR, but instead Kuiper linux, how would I affect this change? Would I change the dev-tree in some specific way that you could recommend?

Thank you,

Luke

Both use the same driver so it doesn't matter. There is no API to disable Quad cal at startup with the Linux driver. It is expected that you can powerdown your PA to calibrate the device then power it back up.

-Travis

Travis,

Is there some way to hold the device in reset until I am ready to send modulation?

I understand that linux wants to boot the driver, and configure everything, but I am having a hard time accepting this compulsory emission. My application, and I feel many others, can't really tolerate spurious transmissions. The should only occur once power is stable/everything is configured, but so often this cannot be guaranteed in the field.

Is there really no way to address the "silent" mode that some applications demand? Can I power down the LO from boot and then bring it up when I'm ready? It seems like there should be some workaround.

Gratefully,

Luke

The driver is not written to remain in reset until user interaction. You would need to modify it. Or load it after the fact with something like an overlay.

-Travis