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

[Tellrell White]

Thanks for your response Baskshi. I looked at the code you implemented,  in addition to looking at the information on message passing on doxygen.

I've tried creating my own code that would adjust the gain by a certain amount(0.5 dB) after receiving a certain number of samples. However, after the block receives the required number of input samples, I want it to send out 12 0's in addition to sending the sink block a command to adjust the gain. I believe sending out the 12 0's should be handled in the forecast function but I'm not sure if I'm going about doing this correctly.

I've attached my flow graph and the code for this "gain setter" block. Any feedback would be great.

Tellrell

On Thursday, July 13, 2017 2:48 PM, "Bakshi, Arjun" <address@hidden> wrote:

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

gain_test.grc
Description: application/gnuradio-grc

Gain_set.py
Description: Text Data