Re: [Discuss-gnuradio] Enable/Disable TX ports in B210 in 2x2 setup

Hi Marcus/Muller,

 

I was trying a simple flow graph to implement what you said earlier :

"
If it were *my* problem, I'd probably have a couple of vector sources of alternating 1s and 0s, interpolate them up to the desired sample rate
   X the switching interval, and multiply the stream going into the USRP by that stream of 1s and 0s.

"

 

To make things simpler, I am trying:

 

Vector source (0,1) multiplying with a sine wave. As an out put I want 1 period of sine wave (say 1kHz frequency) and the next period to be zero. I believe I need to set the sample rate and match this period with the vector source.

 

Can you just help be in deducing this please. Having hard time to sort this out ☹

 

Thanks

Ayaz

 

From: Müller, Marcus (CEL)
Sent: Wednesday, July 18, 2018 6:34 AM
To: discuss-gnuradio@gnu.org; ayazmahmud@hotmail.com; mleech@ripnet.com
Subject: Re: [Discuss-gnuradio] Enable/Disable TX ports in B210 in 2x2 setup

 

The Selector block comes from the "deprecated" category, and that for good reason: Don't use it, it causes a huge teardown/setup effort behind the scenes, and not all is guaranteed to work.

 

Follow Marcus' advice with the 0/1 multiplication and offset tuning.

 

Best regards,

the other Marcus

On Tue, 2018-07-17 at 23:06 +0000, Ayaz Mahmud wrote:

Hey Marcus,

 

I think the Selector block works well with my setup.

 

But I need a solution with which I can do a dynamic change in the input/output index. Can you let me know how is this possible

 

Ayaz

 

From: Ayaz Mahmud
Sent: Tuesday, July 17, 2018 4:39 PM
To: Marcus D. Leech; "Müller, Marcus (CEL)"; discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Enable/Disable TX ports in B210 in 2x2 setup

 

Hi Marcus,

 

The situation still is same.

 

By browsing the archive I found some switching of blocks with SELECTOR. Is there any example that will be helpful on how this block actually functions ?

 

Thanks

Ayaz

 

From: Marcus D. Leech
Sent: Monday, July 16, 2018 1:26 PM
To: Ayaz Mahmud; "Müller, Marcus (CEL)"; discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Enable/Disable TX ports in B210 in 2x2 setup

 

On 07/16/2018 02:05 PM, Ayaz Mahmud wrote:

Hi Marcus,

 

The issue is even I put the vector source toggling with 1 and 0s it transmit a signal. So I need something that will not transmit at all and switch between these 2 radio chains.

 

Thanks,

Ayaz

You're probably seeing the residual LO leakage during periods of "no transmit".

You can try using offset-tuning to move the leakage out-of-band:

Use:

uhd.tune_request(frequency,offset)

In the UHD sink for the "frequency" field.

 

From: Marcus D. Leech
Sent: Saturday, July 14, 2018 8:15 PM
To: Ayaz Mahmud; "Müller, Marcus (CEL)"; discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Enable/Disable TX ports in B210 in 2x2 setup

 

On 07/14/2018 06:40 PM, Ayaz Mahmud wrote:

Hi Muller / Marcus,

 

I got the testing right now, but unfortunately it doesn't work while I put it in my original file.

 

Here is the attached .grc where I have used vector source as input and multiply a period with 1 and then with zeros on one radio channel and opposite on the other.

 

Can you please have a look, and check if I am doing anything wrong ?

 

Ayaz

 

You're asking us to debug a very complex signal flow.

Why don't you try something a *lot* simpler to get the TX-flow-switching-logic correct first, and then work up from there.