Which stage is second in the pulse code modulation (PCM) process?

In the pulse code modulation (PCM) process, the second stage is quantization. This stage comes after sampling, where the continuous analog signal is sampled at specific intervals to create discrete values. During quantization, these sampled values are then approximated to the nearest value within a set of predetermined levels, resulting in a limited number of possible values. This process is crucial because it transforms the infinite possible amplitudes of the analog signal into a finite representation that can be encoded and later transmitted or stored digitally.

Quantization helps in achieving a balance between accuracy and data rate. If done improperly, it can lead to quantization noise, which might affect the quality of the signal. This is why understanding the quantization process is vital for anyone involved in digital signal processing and PCM.

In the broader context, the other stages either occur before or after this crucial step. Sampling is the first stage of the PCM process, where the analog signal is captured at discrete intervals. Encoding, which follows quantization, is where these quantized values are converted into binary code for digital transmission or storage. The analog stage refers to the original continuous signal that is being processed and is not a part of the PCM stages after sampling.