Schematic diagram of multi-carrier frequency modulation

Multi-carrier frequency modulation is a method of modulating the data of one signal (one remote signal) to multiple carrier frequencies for transmission, as shown in Figure 22-8.
    In the multi-carrier frequency modulation method, the serial data is converted into parallel data through serial-to-parallel (s/P) conversion, that is, it becomes IV data. Each
data is modulated onto a different carrier frequency and then combined for transmission. At the receiving end, the data is demodulated from different carriers and passed
through their respective low-pass filters (LPF). Send it to the parallel and serial conversion circuit to recover the data completely.