[Discuss-gnuradio] Maximum Frequency Hopping speed of the Ettus Transceiver RF frontends

[Sergio Benco]

Dear all, 

        I've read on the Ettus transceiver daughterboards datasheet that the
PLL lock time is around 200us, which makes it suitable for some FH
systems (eg. Bluetooth). I've tried to measure this time (plus any other
possible latency between the Host and the USRP2) by timestamping a
sequence of "set_center_freq()" calls that swaps between two different
frequencies (2.412 GHz and 2.413 GHz) many times in a top_block run
(using only C++, not Python).

The resulting measured time values are around 400us using a USRP2 +
XCVR2450 and a quadcore host. 

1) How was the 200us time value measured? 
2) Is it possible to obtain a sustained hopping rate of 1/200us?  
3) If yes, how can we get that value?


Best regards,


Sergio Benco