Re: [Discuss-gnuradio] Tune UHD - as fast as possible

[Ed Criscuolo]

On 2/10/12 4:14 AM, Marius Ciepluch wrote:
> So if someone knows how I can implement a callback or a polling function
> to make the device tune for real, but as fast as possible, that'd be
> very helpful.

In the past, I've done external tuning via GRC with the following:

Create a variable block (ie - "frequency"),  and put the name in
the frequency parameter of the UHD-sink block.

Create a subgraph consisting of a UDP source block and a variable
sink block, aimed at the "frequency" variable.

Use an external program to send a UDP packet to the port number
of the UDP source block.  The packet should contain a single
integer representing the frequency.  Pay attention to byte-order.

I've used this setup to apply doppler correction from an external
program when receiving telemetry from a spacecraft.  We were only
sending packets about once per second, so I don't know how fast
this setup will go, but it's worth pursuing.

@(^.^)@  Ed