Single sideband (SSB) modulation was introduced in amplitude modulation (AM) to address the issue of bandwidth efficiency. In traditional AM, the modulated signal consists of a carrier wave and two sidebands: the upper sideband (USB) and the lower sideband (LSB). These sidebands are symmetrical mirror images of each other and carry the same information.
However, both sidebands contain redundant information since they are identical, which results in inefficient use of bandwidth. This redundancy leads to wasteful utilization of power and bandwidth resources. Additionally, transmitting both sidebands requires double the bandwidth compared to transmitting just one sideband, leading to limitations in the number of simultaneous transmissions.
Single sideband modulation overcomes these drawbacks by transmitting only one of the sidebands (either USB or LSB) along with the carrier wave, while completely suppressing the other sideband. This results in a significant reduction in bandwidth requirements, allowing for more efficient use of the available spectrum.
By transmitting a single sideband, SSB modulation improves bandwidth efficiency and enables the transmission of more signals within the same frequency spectrum. It also provides enhanced signal-to-noise ratio compared to traditional AM since the total transmitted power is concentrated in a single sideband instead of being spread across two sidebands.
SSB modulation is commonly used in applications where bandwidth efficiency is crucial, such as long-distance communication, amateur radio, and certain forms of radio broadcasting.