Receiver Path Description For 806-870 Mhz; Receiver Path Description For 380-430 Mhz; Frequency Generating Section Description; Global Positioning System (Gps) Section Description - Motorola MTP850 S Service Manual

OVERVIEW
The Cartesian Loop output power passes to the antenna through the Antenna
Switch, Harmonic Filter and Duplexer.
Receiver Path Description for 806–870 MHz
The receiver section in the terminal 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 Antenna Switch, Limiter, 10dB Step Attenuator,
Front Filter, LNA integrated with 23dB Step Attenuator and 40dB of AGC
continuous attenuation, Pre-selector SAW Filter, Balun, Half-Life Mixer, 1-pole
filter, and the Tomahawk IC which consists of all the base band receive chain.
Receiver Path Description for 380–430 MHz
The receiver section in the terminal 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.

Frequency Generating Section Description

The frequency generating section provides description of the following main
components: Tomahawk IC fractional-N Synthesizer, Escort synthesizer,
Reference oscillator, Main VCO, Tx VCO and buffer.

Global Positioning System (GPS) Section Description

The GPS section includes the following main components: Duplexer, Front filter,
LNA, Post Filter, SiRF Instant GSCi-5000 IC, TCXO, RTC, and Level Shifter.
The GPS in the radio is based on the SIRF Instant GSCi-5000 IC, which
comprises a standalone ROM-based multimode GPS receiver in a single chip
BGA package.
MTP850 TETRA Handportable Terminal / Basic Service Manual 3 - 3