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see also Quad Delta-Sigma Board
Or that external article: on mbed.org
The laodcell was connected with a 6-wire configuration to the evaluation board of the AD7190.
The samplerate was set to 10 S/s, chopping enabled (continuous offset and gain correction).
The analog 5V supply was powered from the RIGOL DP832, which has a very low noise level.
We measured an astonishing low noise level of about 50nV(rms).
Here we evaluated the possibility to use a loudspeaker as a low-frequency microphone. Due to lack of shielding of electromagnetic fields, the coil picks up a huge amount of signals, which are not related to acoustic sound waves.