or example, for stereo information processing in analog FM radio broadcasting systems, and together with phase modulation it is used in many modern systems, such as digital radio and TV broadcast systems. 4.2.2.2 SSB Modulation Conventional AM doubles the bandwidth of the message wasting bandwidth in addition to power. Suppressing one of the sidebands reduces the transmis- sion bandwidth and leads to SSB modulation, as shown in Figure 4.5. The bandwidth of a transmission channel is an especially important restriction of the carrier systems in the telecommunications networks. SSB modulation is used in the analog carrier systems that are designed to transmit as many telephone channels as possible through a bandwidth-limited chan- nel such as a cable. SSB modulation doubles the capacity (the number of speech channels) compared with AM and SCDSB. 4.2.2.3 VSB Modulation Consider a modulating signal, for example, the video portion of a television signal, that has a very wide bandwidth and significant low-frequency con- tent. The bandwidth conservation principle argues in favor of SSB modula- tion, but practical SSB systems have a poor low-frequency response because of the filtering of the other sideband. The SCDSB would be better for this kind of application but it requires a double bandwidth. Clearly, a modula- tion scheme that negotiates a compromise between SSB and SCDSB is required and this is called VSB modulation. Transmission VSB modulation is derived by filtering SCDSB (or AM; VSB is often used with a carrier) in such a fashion that one sideband is passed on almost completely while just a trace, or vestige, of the other sideband is included. In the receiver detection circuitry the vestige of the lower sideband is added to the upper sideband. This improves the quality, making the frequency response flat to very low frequencies of the message. This method is used in analog TV video transmission. All of the modulation methods described in this section belong to the class of linear CW modulation method. Consider th