Private Communication Systems
Mobile Phones
Service Manual C25 / C2588 V 1.0 ICP CD ST
R. Fleuren
Sm_C25_lvl2_v10_w97 Page 18 of 32 02/99
• Mixer to mix down the IF signal to the baseband, generating and
inphase (I) and a quadrature (Q) signal.
• Offset compensation for the I/Q signals.
5) Transmitter Circuit PMB 2255
This circuit provides the IF synthesizer, the I/Q modulator, prescalers to regulate the
RF synthesizer and a buffer stage to feed the PA.
The antenna switch is mechanical, located in the connector for the external antenna.