The method described by pulse-code modulation takes a given analog wave and digitizes it by sampling the value of the wave at given points and assigning the nearest whole number. Sampling rates typically range around eight thousand Hz for music files. A higher sampling rate gives a more accurate picture of the wave, and results in higher quality audio.
Pulse-core modulation is used most often as the method behind another file format. PCM files are rare to see, but many WAV and RAW files will use pulse-core modulation to digitize analog signals. WAV and RAW files, like PCM, do not carry any metadata with them, and are frequently compressed into other formats that do support metadata, such as MP3.
Most music players will not recognize a PCM file; neither iTunes nor Windows Media Player list PCM as a supported file format. However, because PCM files are very similar to most WAV files, renaming a PCM file to end in WAV may allow you to play it in your media player. You can also try playing the file in VLC Media Player, which doesn't rely on the same codecs as most popular music players.
MP3, a common music file format, supports 2 channels of audio, known as stereo sound. PCM as a file type unfortunately only supports a single channel of audio, known as mono. While pulse-code modulation may be used to digitize other file formats with stereo sound, PCM files operate in mono format, leaving them undesirable for audio enthusiasts.