Figure 49 RF block diagram RM-604 using RF ASIC N7500The RF block diagram uses RF ASIC N7500 (Vapaus) that performs the RF back-end functions of receive andtransmit function of the cellular transceiver.Receiver (RX)An analogue signal is received by the phone's antenna. The signal is converted to a digital signal and is thentransferred further to the baseband (e.g. to the earpiece).The receiver functions are implemented in the RF ASIC.Signals with different frequencies take different paths, therefore being handled by different components.The principle of GSM and WCDMA is the same.Transmitter (TX)The digital baseband signal (e.g. from the microphone) is converted to an analogue signal, which is thenamplified and transmitted from the antenna. The frequency of this signal can be tuned to match the bandwithof the system in use (e.g. GSM900).The transmitter functions are implemented in the RF ASIC.Even though the GSM and WCDMA signals are sent via different components, the principle of the transmissionis the same.RM-598; RM-604System ModulePage 5 –24 COMPANY CONFIDENTIAL Issue 1Copyright © 2009 Nokia. All rights reserved.
