Definition: baseband

Electronic data in their original form. Baseband refers to analog or digital data before being intermixed with other data. See multiplexing and modulation.

Examples
The output of an analog microphone is baseband because it is only voice frequencies. When an FM station's carrier frequency in the receiving radio is stripped away (demodulated), the original audio signal that one hears is the baseband signal. See frequency modulation and carrier frequency.

Ethernet transmission is considered baseband, because signals are not intermixed and occupy the full bandwidth of the line. In fact, "base" is part of the Ethernet version name (see 10Base-T and 100Base-T).

Decompress to Baseband
When a compressed digital signal such as MP3 is transcoded to another audio format, it is first decompressed back to the original bit rate (baseband signal) before it is compressed into the new format; for an example, see aptX. See baseband processor.

Baseband Video

It is not common to see the term baseband used in a consumer product. Nevertheless, this earlier cable TV box manual referred to the video signal "not mixed with audio" as baseband video. See composite video.