AUDIO SIGNAL - electric alternating voltage
<aside> 📎 For complex signals, the amplitude is determined for the period of the fundamental oscillation. It does not have to be symmetrical.
</aside>
In signal processing and related disciplines, aliasing is the overlapping of frequency components resulting from a sample rate below the Nyquist rate. (undersampling)
<aside> 📎 Nyquist Theory
In order for the signal to be correctly restored, the sample rate should be at least double the frequency of the original signal
$$ f_{sampling rate} = 2f_{signal} $$
</aside>
But even if the sampling theorem is followed, aliasing may also occur if the signal to be sampled is superimposed by a noise signal containing frequency components higher than the Nyquist frequency
Nyquist frequency = the minimum rate at which a signal can be sampled without introducing errors, which is twice the highest frequency present in the signal.
<aside> 📎 Summary
The purpose of a sample and hold circuit in an ADC is to provide a stable and accurate input signal for conversion to a digital value. By holding the input signal constant for a short period of time, the circuit ensures that the ADC is measuring the signal accurately and reliably.
</aside>
In an analog to digital converter (ADC), a sample and hold circuit is used to capture an analog signal at a precise moment in time and hold that value long enough for the ADC to convert it into a digital value.
When an analog signal is being measured, it is continuously changing over time. In order to convert this signal to a digital value, the ADC needs to take a snapshot of the signal at a specific moment in time.
This is where the sample and hold circuit comes in. The circuit is designed to take a sample of the signal at the input and hold that value constant for a period of time. This allows the ADC to convert the sample to a digital value without worrying about changes in the input signal during the conversion process.
Quantization is the second step after dissolution into discrete time periods. Individual time segments are evaluated in their amplitude and rounded to the next valid value (quantized).
