GSM noise

Good day, I've constructed a simple circuit where Arduino Pro Mini is connected to SIM900 based GSM-module. It works fine, but when I make a call, I hear terrible GSM noise on receiver phone. If I reduce the microphone gain the noise is reduced also, but I can't remove it at all. It's very hard to recognize the voice behind the noise.

Is there any solution for my problem?

What kind of microphone did you connect (Link)?

I'm using EM-6050 ( http://vagapov.com/download/em-6050.pdf )

And how did you connect it to the SIM900? Did you use the circuit as described in chapter 4.6 of the datasheet? Please provide the complete schematics of your setup.

I'm using GSM module http://www.aliexpress.com/item/1pcs-new-GPRS-GSM-SIM900-Shield-module-development-board-DTMF-MMS-positioning/2020267594.html

It looks like microphone just connected to appropriate SIM900 pins without any additional schematic. Do you think that capacitors from SIM900 datasheet will help?

I would at least try it. Using this components is better anyway (even if only for protection of you setup). If the datasheet tells you to use this components they may be necessary for the integrated electronics. If you don't comply to the advises of the datasheet you cannot complain about noise.