Re: [Discuss-gnuradio] OOT Block to Automatically adjust Transmit Gain

[Bakshi, Arjun]

Couldn't figure out how to reply from the digest, so I'm making a new post. New to this.

Original message/context:

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From: Tellrell White

I'm currently in the process of creating a block in python that does two things; takes in? a certain number of input items, and once it reaches a certain number of input items 2) it sends a command to the UHD USRP sink block to adjust its gain by a certain amount.

I have a few questions. 1) Is it even possible to create a single block that can accomplish both these tasks? 2) How exactly do I make this block issue the command to adjust the gain after it receives a certain number of values??Below is some code that I currently have constructed for this purpose. I'm pretty new to python so I'm sure this code is probably not the most efficient way but any suggestions are welcome.

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Hey Tellrell,

1) I think it can be achieved using 1 block. The block will need to output a message with "gain" and the gain value whenever the input matches your condition. Connect the output message port to the USRP sink's command port. Message should be a pmt that looks something like ("gain", value).

More info on the command port: https://gnuradio.org/doc/doxygen/page_uhd.html#uhd_command_syntax

2) I went ahead and implemented something as an example. Increases gain upto a limit and then starts over again. See attached code, xml for block, rxed signal plot, and flowgraph pic.

I'm new to this too, so hopefully other will correct my mistakes.

Regards,

AB

set_gain.py
Description: set_gain.py

channel_set_gain.xml
Description: channel_set_gain.xml

flow
Description: flow

gain_setter.png
Description: gain_setter.png