Motorola MTP810 EX, Basic Service Manual

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OVERVIEW 3 - 3
The transmitter path consists of a Cartesian Loop that contains the forward and
feedback paths. The forward path includes the JAVELIN IC, BALUN, Attenuator,
Power Amplifier and Isolator. The Loop feedback path includes the directional
coupler, attenuator, BALUN, and JAVELIN IC.
The Cartesian Loop output power passes to the antenna through the Antenna
Switch, Harmonic Filter and Duplexer.
Receiver Path Description
The receiver section in MTP810 Ex is based on the DCR (Direct Conversion)
technology, the main concept of this technology is down converting of the RF
signal directly into a base band signal, skipping the intermediate stage of IF
signal.
The receiver path includes the Duplexer, Antenna Switch, Limiter, 10dB Step
Attenuator, Discrete Front Filter, RF switches, LNA integrated with 30dB Step
Attenuator, 22dB of Gain and 40dB of AGC continuous attenuation (in parallel
with LNA bypass feature), Discrete Post-selector Filter, BALUN, Half-Life Mixer,
one-pole baseband filter, and the Tomahawk IC which consists of all the base
band receive chain.
Global Positioning System (GPS) Section Description
The GPS section includes the following main components: Duplexer, Front filter,
LNA, Post Filter, SiRF Instant GSCi-5000, RTC, TCXO, Logic Buffer, and Level
Shifter.
The GPS in the MTP810 Ex is based on the SIRF Instant GSCi-5000, which
comprises a standalone ROM-based multimode GPS receiver in a single chip
BGA Package.