Intermodulation E******* 850

[Gonzalovillalba]

hello, I'm new here and i have this problem.
When I make a call using a 2G terminal (830MHz-835Mhz), Ericcson 850 BTS, I see with the spectrum analyzer (Rodhe&Shwartz PR100) something like a pulse when the call initializes (attached image) The problem is that those pulses appear in the 3G spectrum (910Mhz-915Mhz).
The 2G technology and the 3G technology belong to two different companies.
I want to know if someone else has the same problem, Thanks.

Sorry for my bad english.