When amplitude modulating a carrier signal with a frequency band, two sidebands are formed below and above the carrier frequency, both of which have the information content of the frequency band: the lower sideband and the upper sideband. Both sidebands have identical information content and the same bandwidth
. For example, if the carrier signal has a frequency of 1 MHz and is modulated using amplitude modulation with a frequency band from 2 kHz
to 20 kHz, then the following sidebands are formed: The lower sideband, lower sideband (LSB), which starts at 980 kHz and ends at 998 kHz and the upper sideband, upper sideband (USB), which starts at 1.002 MHz and ends at 1.020 MHz. Between the two sidebands is the carrier frequency.double-sideband modulation.