How can you design a system to compress a digital signal?

2 Compression methods

There are two main types of compression methods: lossless and lossy. Lossless compression preserves the original signal without any distortion or degradation, but it can only achieve a limited compression ratio. Lossy compression discards some information from the signal, resulting in a lower quality but a higher compression ratio. The choice of compression method depends on the trade-off between quality and size, as well as the application and user requirements of the signal.

3 Compression algorithms

Compression algorithms are the specific rules and procedures that implement the compression methods. There are many different compression algorithms, each with its own advantages and disadvantages. Some of the common compression algorithms are Huffman coding, run-length encoding, Lempel-Ziv-Welch (LZW), discrete cosine transform (DCT), and wavelet transform. Compression algorithms can be classified into two categories: entropy coding and transform coding. Entropy coding exploits the redundancy in the signal by assigning shorter codes to more frequent symbols, while transform coding transforms the signal into a different domain where it can be represented more compactly.

4 Compression standards

Compression standards are the agreed formats and specifications that enable interoperability and compatibility between different compression systems and devices. Compression standards define the structure, syntax, and semantics of the compressed signal, as well as the methods and parameters for encoding and decoding. Some of the widely used compression standards are JPEG, PNG, GIF, MP3, AAC, MPEG, H.264, and ZIP. Compression standards can be general or specific, depending on the type and purpose of the signal.

5 Compression system

A compression system is the combination of hardware and software components that perform the compression and decompression of the digital signal. A compression system consists of four main elements: an encoder, a decoder, a channel, and a source. The encoder converts the input signal into a compressed output signal using a compression algorithm and a compression standard. The decoder reverses the process and reconstructs the original signal from the compressed input signal. The channel is the medium or interface that transmits or stores the compressed signal. The source is the origin or destination of the signal, such as a microphone, a speaker, a camera, or a monitor.