Subband

A frequency range that is a fraction of a larger, overall band of frequencies, typically used in signal processing, telecommunications, and audio engineering. Subbands are created by splitting a wideband signal into narrower frequency components, allowing for more efficient data transmission, selective filtering, and noise reduction. Each subband can be processed and modulated independently, improving overall system performance and adaptability. This technique is crucial in modern communication standards and audio compression methods.

Subband meaning with examples

• In digital audio broadcasting (DAB), the audio signal is split into multiple subbands, each representing a small portion of the audible frequency spectrum. This allows for efficient encoding and decoding, reducing the amount of data needed for transmission while still preserving sound quality, offering better service.
• Orthogonal Frequency-Division Multiplexing (OFDM), used in Wi-Fi and 4G/5G cellular technology, employs subbands to transmit data across multiple parallel channels, improving spectral efficiency and mitigating the effects of multipath fading. This provides higher bandwidth and improves signal reception.
• A video compression algorithm used to split a visual stream into a collection of subbands allows for separate handling of various resolutions and different parts of an image by using techniques like the Discrete Wavelet Transform (DWT) that optimizes compression rates.
• Noise reduction techniques often isolate noise from the signal in different subbands, allowing for selective filtering and removal of unwanted audio artifacts while retaining the clarity of the original signal. This improves signal to noise ratios and decreases distractions.