Pulsecode

Pulsecode is a term used in digital communications to describe the binary code word that represents a single sample in a pulse-code modulation system. In a typical PCM chain, an analog input is sampled at regular intervals; each sample is quantized to the nearest discrete level and then encoded as a binary word. The resulting sequence of code words forms a pulse-code stream suitable for transmission or storage.

Historically, pulsecode concepts emerged during the development of digital telephony in the mid-20th century, with early work at major research laboratories and later standardization by international bodies. Modern usage usually refers to pulse-code modulation (PCM), a widely adopted form of digital encoding for audio and voice signals.

Key characteristics include the sampling rate, the bit depth per sample, and the quantization law. Common configurations include 8- to 24-bit depth and sampling rates such as 8 kHz (telephony), 44.1 kHz (CD-quality audio), and 48 kHz (professional video). Telephony often employs nonlinear companding (mu-law or A-law) to improve dynamic range within 8-bit or 12-bit channels before expansion at the receiver.

Applications span telecom networks, broadcast audio, digital recording, and storage formats. PCM’s advantages include resilience to noise, straightforward synchronization, and compatibility with binary digital systems; its trade-offs involve increased bandwidth compared with analog signals and quantization noise introduced by finite bit depth.

In contemporary discourse, the term pulsecode is largely synonymous with PCM, though the specific phrase is more common in historical contexts.