Receiver Path Description; Frequency Generating Section Description; Global Positioning System (Gps) Section Description - Motorola TETRA MTH800 Basic Service Manual

Description
The cartesian Feedback output power passes to the antenna through the
Isolator, Antenna Switch, Harmonic Filter and Duplexer.

Receiver Path Description

The receiver section in MTH800 is based on the novel 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,
Tunable Filter, LNA integrated with 28dB Step Attenuator and 40dB of AGC
continuous attenuation, Pre-selector Band Pass Filter, Balun, Half-Life Mixer, 1-
pole 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, Instant GSCi-5000 IC, RTC, and TCXO.
The GPS in the MTH800 is based on the SIRF GSCi-5000 IC, which comprises a
standalone ROM-based multimode GPS receiver in a single chip BGA Package.
MTH800 TETRA Handportable Terminal / Basic Service Manual 3 - 3