source encoding

Source encoding is a crucial function in digital communications systems aimed at reducing redundancy in digitized signals to minimize the number of bits needed for data transmission. This process is accomplished by a source encoder, often working alongside an analog-to-digital converter, to make the most efficient use of a telecommunications medium's limited bandwidth.1

Key techniques for source encoding include:
* Huffman codes: These codes assign variable-length binary codes to data symbols based on their probabilities of occurrence, using shorter codes for more frequent symbols.1
* Lempel-Ziv algorithm: This adaptive method constructs a codebook from previously encountered sequences, allowing it to efficiently encode data without prior knowledge of symbol probabilities.2
* Run-length codes: These are effective for data with long sequences of identical bits (runs), such as those found in fax transmissions. They encode the length of the run rather than each individual bit.3

While source encoding reduces redundancy, channel encoding (like convolutional encoding) adds redundancy to protect data against transmission errors caused by noise.4