The TDA8205 is essentially divided into two signal processing sections. The first section handles all the NICAM signal acquisition, the QPSK demodulator and clock and data recovery circuits. The key point to note about this section is the dual frequency synthesiser. By use of only one quartz crystal, the IC is able to demodulate QPSK signals from either system I or system B/G in an automatic way. The second section of the TDA8205 manages the analog parts of the twin digital-to-analog converters (DACs) and all filtering and audio switching downstream of the DACs. A simple serial bus from the TDA8204 allows control of the switch functions by the CTV system microcontroller.