Flowgraph time, or getting number of samples since start of flowgraph

GNU Radio
1

Hello:

Does GNU Radio keep track of time, or sample count, or something similar
as a flowgraph runs? How can I query the current “flowgraph time”, from
within my flowgraph, if such a thing exists?

More specifically, I have a Signal Source connected to a USRP2 Sink in
order to generate a tone. Is there any way to query the Signal Source
for how many samples it has created since the flowgraph started?

Thanks a lot.

Steve McMahon

2

On Sun, Dec 5, 2010 at 11:24 PM, Steve M.
[email protected] wrote:

Hello:

Does GNU Radio keep track of time, or sample count, or something similar as a
flowgraph runs? How can I query the current “flowgraph time”, from within my
flowgraph, if such a thing exists?

More specifically, I have a Signal Source connected to a USRP2 Sink in order to
generate a tone. Is there any way to query the Signal Source for how many samples
it has created since the flowgraph started?

Thanks a lot.

Steve McMahon

Time would indicate that there is a concept of a sample rate, which
isn’t always true and not every block is told what the sample rate is,
anyways, even if the items are clocked. However, the next branch does
now keep track of the number of items read and written for each
input/output of each block. You can get these by calling the
nitems_read and nitems_written. It returns a 64-bit number of the item
count since the start of the flow graph.

Tom