The RF section has transmitter and receiver circuits including mixer, local oscillator for channel selection, the receiver, low noise amplifiers and transmitter power amplifier.
The baseband section contains the vocoder with it’s A/D converter and D/A plus a digital signal processor chip that handles many processing functions like baseband and intermediate frequency filtering, modulation, demodulation and mixing. The vocoder is a circuit which converts voice into digital format and compresses digital data.
An embedded controller handles all the digital control and signaling, hand offs and connection and identification of operations that takes place transparent to the subscriber. It also takes care of running display and key board and all other user functions such as number storage, auto-dialing and caller ID etc. The embedded controller is a fast 32 bit microprocessor with considerable RAM, ROM and flash memory.
