PCMjärjestelmien

PCMjärjestelmien refers to "PCM systems" in Finnish. PCM, or Pulse Code Modulation, is a method used to digitally represent sampled analog signals. It is the standard for digital audio and telecommunications. A PCM system digitizes an analog signal by taking discrete samples of its amplitude at regular intervals and then encoding these samples into a binary code.

The process of PCM involves several key steps. First, the analog signal is filtered to remove frequencies outside the desired range, a process known as anti-aliasing. Next, the filtered signal is sampled at a specific rate. The Nyquist-Shannon sampling theorem dictates that the sampling rate must be at least twice the highest frequency present in the signal to avoid aliasing. Following sampling, the amplitude of each sample is quantized, meaning it is assigned a discrete numerical value from a predefined range. Finally, these quantized values are encoded into a binary format.

PCM systems are widely used in various applications, including digital audio recording and playback (like CDs and digital radio), digital telephony, and digital video transmission. The quality of a PCM system is determined by its sampling rate and bit depth, which refers to the number of bits used to represent each sample. Higher sampling rates and bit depths generally result in more accurate representations of the original analog signal and thus higher fidelity. Despite the development of more advanced compression techniques, PCM remains a fundamental technology in digital signal processing.