User's Manual

APPLICANT: MOTOROLA EQUIPMENT TYPE: ABZ89FC4827
User / Operational Manual
Functional Description / Operation of Modules (Draft)
EXHIBIT D1-6
Receiver Overview
The Receiver Circuitry accepts receive RF signals from the site receive antenna, performs filtering and dual
conversion, and outputs a digitized receive signal to the SCM. The receiver module has an on-board preselector.
The receive signal is input from the site receive antenna to the receiver module, or to an external preselector filter
(a separate assembly attached to the rear of the base station / repeater which provides highly selective bandpass
filtering). The signal is fed through a low-pass filter, varactor tuned preselector, RF amplifier and image filter to the
RF input of the first mixer. The filtered signal is mixed with an injection signal generated by the receive synthesizer
/ VCO, resulting in a first i-f (intermediate frequency) signal. The injection signal frequency is determined by
frequency programming data from the SCM via the SPI bus. The specific frequency of the first i-f depends on the
frequency band of the base station / repeater.
The first i-f signal is filtered and input to a custom receiver IC. This component contains circuitry for generating the
second injection signal, mixing down the first i-f to 2.25 MHz, amplification, and A/D (analog-to-digital) conversion
of the second i-f signal, resulting in a digitized receive signal. This signal is fed as differential data to the SCM.
The Receiver Module contains the following circuitry:
• Frequency Synthesizer Circuitry – consists a phase-locked loop and Voltage-Controlled Oscillator (VCO),
generates the first LO injection signal
• Varactor-tuned Preselector Filter – provides bandpass filtering of the station Receiver RF input
• Receiver Front End Circuitry – performs filtering, amplification, and the first down conversion of the
Receiver RF signal
• Custom Receiver IC Circuitry – consists a custom IC which performs the second down conversion,
filtering, amplification, and analog-to-digital conversion of the receive signal
• Analog to Digital Converter (ADC) Converter Circuitry – converts analog Receiver status signals to digital
format for transfer, upon request, to the SCM
• Local Power Supply Regulation – accepts +8V, +10V and +14.2V inputs and outputs +2.775V, +3.3V, +5V,
+10V, and +14.2V operating voltages
Input and Output Connections
The following shows the Receiver module input and output external connections.