Is file sink block resetting USRP?

Hi all,

I use a file sink block in my flow graph to record samples from a USRP
N210. I start the flow graph and then after some time starts to record
using the file sink block by switching it on using a selector block.

My question is, when the file sink is activated, is the flow graph in
any
way restarted?

I have attached a plot of the real part of the samples I recorded. I see
strange behavior in the beginning as I would expect if I instantly
started
to record when the flow graph is started (due to the time it takes for
the
radio to tune in).

The reason to why I am asking is that I suspect that the phase of the
signal is changed when I start to record, and maybe this could explain
why.

Best regards,

Carl

On 05/27/2015 05:52 PM, Carl O. wrote:

see strange behavior in the beginning as I would expect if I instantly


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My recollection is that the selector blocks stop the graph, reconfigure
it, and start it again, which means source streams probably get
restarted.

When I’ve need to do this in the past, I just tie the filename to a
variable that is controlled by my “start recording” button–when I’m not
recording, the file sink is set to “/dev/null”, and when I am
recording, it’s set to the target file.

On 27.05.2015 18:30, Marcus D. Leech wrote:

On 05/27/2015 05:52 PM, Carl O. wrote:

Hi all,

I use a file sink block in my flow graph to record samples from a USRP
N210. I start the flow graph and then after some time starts to record
using the file sink block by switching it on using a selector block.

My recollection is that the selector blocks stop the graph, reconfigure
it, and start it again, which means source streams probably get restarted.

That’s right: lock() and unlock() are called, which reset the blocks.
Marcus’ suggestion is the easiest and most effective solution to this;
we also have another block (matrix_multiply_xx) which can act as a
selector that doesn’t call lock() if you require this.

M

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