Re: [Discuss-gnuradio] Dynamically changing bandwidth of QT GUI Frequency Sink

[Jason Hein]

Marcus,

To clarify, assume I set the sample rate at build time with the samp_rate variable within the QT GUI Frequency Sink.  At run time, the bandwidth (x axis) is reflective of this samp_rate.  However, if I have a source block upstream that changes the sample rate via out of band means, I would like that source block to change the samp_rate of the QT GUI Frequency Sink programmatically.  I am able to change the frequency of the QT GUI Frequency Sink programmatically through the message port, but I haven't seen a way to change the samp_rate/bandwidth.

Jason

On Tue, Jul 31, 2018 at 5:56 AM, Müller, Marcus (CEL) <address@hidden> wrote:

Hi Jason,
just to be sure to understand what you need:
Do you mean "zoom in x-axis"?
(because technically, the bandwidth of that display is always Nyquist,
i.e. defined by the sampling rate)

Best regards,
Marcus

On Mon, 2018-07-30 at 16:57 -0400, Jason Hein wrote:
> I have a GNU radio flow graph with a custom data source and I'd like to be able to change the bandwidth displayed on the QT GUI Frequency Sink block dynamically.  Is there a way to do this programmatically?  The QT GUI Frequency Sink block has a message port for programmatic changes to frequency, but I don't see an equivalent means for changing bandwidth.  Is there a way for an OOT block to get a reference to another block to call a public member function?