Re: [Discuss-gnuradio] Failure of sending square wave over USRPs (back-to-back)

[Activecat]

Dear Martin,

On Fri, Mar 14, 2014 at 5:13 PM, Martin Braun <address@hidden> wrote:
> Here's a very brief explanation: The PLL for the synthesizer makes sure the
> locally generated frequency is stable (per-device). It's physically
> impossible to make perfectly aligned oscillators. By throwing money at the
> problem, you can reduce the potential offset. But since you can never get
> rid of it entirely, you also need a mechanism (e.g. a PLL) to lock on the
> incoming signal.

At the receiver side, the received signal is first processed by SBX
daughtercard before being sent it to the host (which is the PC).
The IQ demodulation is performed at the receiving SBX, not at the host.
In this case the clocking of SBX must be synchronized to the received
IQ-modulated signal.
Hence the PLL must be done precisely in the SBX, not in the host, correct?

If the PLL is done at the gnuradio flow graph, then this flow graph
must be able to adjust the local oscillator of the SBX daughtercard,
via softare. Does gnuradio flow graph have this capability?

Regards,
Activecat