With double sideband modulation, the carrier frequency is also transmitted. However, there are two other variants in which the carrier frequency is reduced or suppressed. With the Double Sideband Reduced Carrier( DSBRC), a carrier signal with a greatly reduced level is transmitted, and with the Double Sideband Suppressed Carrier (DSBSC), the carrier signal is completely suppressed.
In the DBSCS method, only the two sidebands symmetrical to the carrier frequency are transmitted, the upper sideband lying above the carrier frequency and the lower sideband lying below it. The carrier signal itself is suppressed in the transmitter and is not transmitted.
The advantage of carrier suppression is the reduced transmit power. Before demodulation, however, a carrier signal must be added at the receiving end. The method can also be used for single-sideband modulation (SSBSC). The DSBSC method is used, among other things, for the transmission of the color carrier in analog television or the transmission of the pilot tone in broadcasting and also for ZigBee.