Transient effect

Hi,

I am using the USRP2 with the XCVR2450 board and I can observe a
transient
effect while receiving the first 200e3 samples( decimation of 5) when
using a
low gain setting (gain: 0 to 20) and no signal was to the input. Has
anybody
observed anything similar and was able to determine where it comes from?

Thanks a lot.

Cheers,
Christoph