First, the microphone converts sounds into voltage. Then, your sound card acts as a very fast digital voltmeter. It measures the voltage as often as 11,025 -- up to 44,100 times per second. You can set this number-of-measurement-per-second parameter using a drop-down combo box "Sampling Frequency" (here it shows 11 kHz) Each measurement is converted into an 8- or 16-bit number called a sample. 16-bit numbers allow for more accuracy in measuring subtle effects. You can select this paramter by clicking on one of the "Bits per sample" radio buttons.