6345Re: Big signal at 0 Hz even with SR40 is off
- Oct 1, 2006
Marco IK1ODO wrote:
Marco is quite right, as demonstrated by these two screen captures. The first is the digitizing process carried on by Adobe Audition, using the onboard AC'97 chipset, with the card input left open. As you can easily see, there is a substantial DC offset produced by the ADC.
There would be also a peak at 0Hz due to DC imbalance of the ADC inputs, but the ADCs used in 24bit souncards have an internal high pass filter cutting under 1 or 2Hz, suppressing that.
The same chipset produced this strong zero frequency peak, entirely caused by the DC offset :
73 Alberto I2PHD
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