The principle of mobile uploading (talking on the phone) is: Firstly, the digital speech signal is processed by the fundamental frequency chip (BB), then converted into a high-frequency analog signal through the Modulator (Modulator), converted into the required frequency by the Mixer (Mixer), the high-frequency analog signal (electromagnetic wave) is obtained by the bandpass filter (BPF), and the signal is enhanced by the power amplifier (PA). Finally, it is transmitted by the transmission receiver (Tx) to the antenna output.