Which type of modulation is generally more efficient in terms of bandwidth used?

Single Sideband (SSB) modulation is generally more efficient than other modulation types, such as Frequency Modulation (FM) or Amplitude Modulation (AM), in terms of bandwidth usage.

SSB works by eliminating one of the sidebands produced in conventional AM transmission, along with the carrier wave, which reduces the bandwidth required for the signal. Traditional AM requires a bandwidth that is often twice the frequency of the modulating signal due to its two sidebands. In contrast, SSB only requires the bandwidth equivalent to the modulating signal itself, allowing for a more efficient use of the available spectrum. This efficiency allows more signals to occupy the same bandwidth, which is particularly advantageous in communication scenarios where bandwidth is limited.

In the context of efficiency, variations of modulation such as FM and AM use more bandwidth because they transmit additional information (like carrier waves and sidebands) that SSB minimizes or eliminates. Hence, SSB is preferred in many communication systems where bandwidth conservation is crucial.