The AD6546 Othello-E transceiver uses a closed-loop polar modulation transmitter and direct conversion receiver
for EDGE/GPRS networks, and the AD6548 Othello-G transceiver supports GPRS operation with a low-cost, small PCB-area solution.
It is a complete radio design that combines multiple functions, including an RF front end, mixed-signal baseband section, frequency synthesizers, two analog-to-digital converters and two direct conversion receivers
in a single chip.
The low-IF (Intermediate Frequency) radio receiver architecture employed in this design, adapted from high-efficiency pager technology, offers lower power consumption and better immunity to interference than direct conversion receivers
In addition, by adopting a new type of system architecture, the design effectively suppresses the DC offset resulting from direct conversion receivers
well below noise levels.
The calibration mode is especially suited for direct conversion receivers
(DCR) during DC-calibration period and offers a better impedance matching at the output compared to the output matching of inactive LNA.