Direct conversion radiotelephone

摘要

The radiotelephone has a direct conversion transceiver, the transmission signal used to modulate the transmission frequency provided by a image selection mixer. This mixes the receiver synthesiser signal with an auxiliary frequency corresponding to a duplex frequency for the transmission system. Pref. the image selection mixer has 2 mixers (12,13), supplied by a power distributor (14) and coupled to an output summator (15), followed by a modulator (18) in the transmission path, connected to the antenna (2) via an amplifier (19), a filter (20) and a TDMA switch (1).