NOISE PROBLEM for NI DAQ 6015E

[Vincent88]

Hi, i'm Vincent

i'm working at a simple progect wich must to acquire a signal from a microphone with the NI DAQPAD 6015.

In Labwiev i had built a procedure that filters and amplifies the signal acquired. My problem is that when i go to

do the fast fourier transformate i notice the noise at the high frequencies that are stronger than the signal acquired, i notice the noise

also when i go to listen the file in wich i had save my acquisition.I had already take some precautions, like to shield wire and microphone utilizing a Faraday's cage but,

although the noise is smaller than before, it's still too bigger than the signal.

Other information:

samples frequency: 44100

acquisition tipe: continuos

samples to read: 250000

Anybody have any idea about this problem?

Thanks for the answer