Re: [Discuss-gnuradio] GR-UHD features incoming

[Piotr Krysik]

Hi Martin,

I'm trying to make use of the new message interface. I'm able to set
center frequency and other parameters with use of it which is great as
now I'm able to make for example a application that scans spectrum
without stopping the flowgraph.

However I expected that after USRP switch frequency because it received
a command a new stream tag would be added to the signal at the moment of
switching (like it happens when for example central frequency is
switched with use of gui widgets). No tag is added though. Is this
intended behaviour?

Best Regards,
Piotr Krysik

W dniu 06.05.2015 o 19:35, Martin Braun pisze:
> The big change for the moment is the enhanced message interface. With
> more blocks using messages for commands (not just data), we're trying to
> standardize how blocks receive messages. If you build the manual
> yourself, you'll see the changes added in
> https://github.com/mbr0wn/gnuradio/commit/72e0c237e06e5214eb2706bd4ac732cef068161c
> to document how we'd like these command interfaces to look like.
>
> UHD already had it's own, home-grown message command interface. With
> this change, it has been adapted to comply with how command messages
> should look like.
> At the same time, a lot of new commands were added. You can now change
> gain, antenna, DSP frequency, LO offset, command times, analog bandwidth
> (where applicable) and sampling rate through messages.
>
> This offers tons of cool new options. Imagine you have a blind OFDM
> receiver, which first estimates the OFDM parameters (center frequency,
> bandwidth, sampling rate) before attempting to blind-demodulate. You can
> have a downstream block change all of these parameters[1] in a kind of
> control loop[2] until they match, then demodulate -- all from the same
> flow graph, just using GNU Radio blocks.
>
>