Yksittäissivutaajuiset

Yksittäissivutaajuiset, often translated as single-sided spectrum (SSS) or sometimes vestigial sideband (VSB) in technical contexts, refers to a transmission method where only one sideband of a modulated signal is transmitted, along with a carrier. This is in contrast to double-sideband (DSB) transmission, where both the upper and lower sidebands are sent.

The primary advantage of transmitting only one sideband is bandwidth efficiency. By suppressing one of the sidebands, the total bandwidth required for the transmission is reduced by approximately half compared to DSB. This is particularly beneficial in broadcasting and other applications where spectrum space is limited.

The transmission process typically involves generating a double-sideband signal and then using a filter to remove one of the sidebands. The remaining sideband, along with the carrier, constitutes the single-sided spectrum signal. A vestigial sideband (VSB) transmission is a variation where a small portion of the unwanted sideband is retained, which simplifies the filtering requirements at the transmitter and receiver.

At the receiver, demodulation of a single-sided spectrum signal requires specialized techniques. While DSB signals can be demodulated using simple envelope detectors if the carrier is sufficiently strong, SSS or VSB signals often necessitate coherent detection, where the receiver needs to reconstruct or synchronize with the transmitted carrier frequency and phase. This complexity is a trade-off for the increased bandwidth efficiency. Historically, SSS/VSB has been employed in analog television broadcasting and some radio transmission systems.