Single Sideband is a derivative of AM where one side and the carrier or suppressed and only one of the sideband signals is left for amplification and transmission. Either the upper or lower sideband may be used. The received single sideband signal is demodulated by means of reinserting a carrier at the proper frequency to heterodyne with the received sideband. The difference in the two signals is the audio that we hear, hence the frequency of the inserted carrier must be correct in order to produce the proper sound. With the absence of a pilot carrier ( not generally transmitted except in commercial applications) there is no way to determine what the carrier should be save for listening and using personal preference as to the familiarity of the received persons voice. This personal preference thing will often cause a group of people in one QSO not to be on the same frequency and the constant retuning to correct the sound causes them to walk up or down the band inadvertently (we hope) causing interference to other QSOs in progress. There are a lot of things that need to be taken into consideration when generating and in the reception of a single sideband signal to keep the distortion down but most single sideband users or not concerned with distortion. These signals or most useful for transfer of information with little regard to the quality and fidelity of the reproduce signal so long as it is intelligible.

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