Re: [Discuss-gnuradio] Confirming uhd.set_command_time is working

[Martin Braun]

On 29.04.2015 09:07, Marcus Müller wrote:
> Hi Doug,
> 
> I've had a multi-page explanation to this phenomenon typed out when it
> hit me. Consider your output:
>> about to issue tune command...
>> -- Successfully tuned to 800.000000 MHz
> Between these two lines, you issue your timed tuning command (to go from
> 700 to 800 MHz) 2s in the future.
> 
> I shouldn't read UHD code any further; there's logically only two options:
> 
>  1. Either, the result of set_center_freq (and also, get_center_freq)
>     comes from a cached value from the PC, in which case it will
>     immediately return, and give you that "newly cached" value (while
>     it's still not valid). In that case, no wait between those two lines
>     of output.

This is it. The tune value is stored in the property tree, and getting
it simply reads it back. I can see how this is non-ideal w.r.t. timed
commands.

Note that the value stored is not necessarily what you write, though. It
gets coerced to something that actually makes sense with your hardware,
which is why this function has its place.

Cheers,
M