User Manual

COMMUNICATION CERTIFICATION LABORATORY TEST REPORT: 73-6560

FCC ID: NQE1005

WinGate 2000 TIM RECEIVER

Functional Description

TIM RECEIVER DESCRIPTION

Overview

The TIM Receiver is a frequency-hopping receiver with an IF

bandwidth of 330KHz. It continuously hops through the 25

specific frequencies it has memorized, stopping just long enough

at each frequency to determine whether valid data is being

received. If valid data is detected, the receiver stays on

frequency long enough to accept the entire packet of data, then

it continues hopping. The receiver detects frequency-modulated,

Manchester-encoded, digital signals using dual down-conversion

architecture. On board processors decode and verify that the

data is good before passing it to a motherboard through a 24-pin

(12x2) connector. Power and control signals are also passed to

the receiver through this connector.

RF Front End

A RF input signal enters the receiver through a female SMA

connector. The signal passes through a SAW band pass filter (915

+/- 13 MHz), an amplifier, and another SAW band pass filter.

Each of these filters has approximately 3 dB of loss while the

amplifier has approximately 18 dB of gain. The signal next

passes through the first mixer, which provides 18 dB of

conversion gain. The Local Oscillator (1

LO) for this mixer

comes from the Synthesizer which provides frequencies from 967.1

MHz to 985.5MHz at approximately –10 dBm. The Intermediate

frequency from this mixer is 61.3 MHz. This IF passes through a

three-section band pass filter, which must be manually tuned. On

the output end of the band pass filter is a resonant shunt that

must be tuned to 66.65 MHz to provide immunity to “half-IF

spurs”. Following this shunt is an impedance match to the input

of the FM Demodulator chip, MC13156.

Synthesizer

The synthesizer consists of a discrete designed Voltage

Controlled Oscillator (VCO) and a Phase Locked Loop (PLL) chip,

MC145191F. The heart of the VCO is a varactor and a single-loop,