Glenayre Document Number: 9110.00148
RL-903 Receiver
Issue 1, Rev. C: 12/10/96
DESCRIPTION
3.1
Introduction
The receiver may be used in three types of applications or in various combinations:
• link repeater receiver for link transmitter (R).
• link receiver with external control (XC) for paging transmitter.
Additionally, in combination with any of these, it may be used as a monitor receiver with
line driver (LD) suitable for telephone lines.
3.2
Physical Description
The receiver is normally mounted in a standard rack and requires two rack units.
Table 2-1 includes physical characteristics. These are the main assemblies:
• RF board
• IF board
• VCO assembly/synthesizer board
• power supply/audio amplifier (PS/A)
• interface board attached to the rear of the chassis (not used in some configurations).
Additional components may need to be installed in order to enable the line driver output.
For views of the receiver, refer to Figure 3-1, Receiver Isometric Front View, Figure 3-2,
Receiver Rear View, and Figure 3-3, Top View of Internal Assemblies. An optional tone-
control board may be used and is mounted on the IF board.
3.3
Simplified Block-Diagram Description
Refer to Figure 3-4, Receiver Functional Diagram. The RL-903 is a self-contained receiver
capable of covering the range of paging and link frequencies between 922 MHz and 960
MHz. Channel spacing is 12.5 or 25 kHz. The radio has a synthesized local oscillator. The
receive frequency is set in 6.25-kHz steps by a selection of DIP switches. The electronic
tuning range is approximately one MHz before manual (coarse) oscillator retuning is
required.
The 900-MHz signal enters at the rear of the chassis and is routed to the RF assembly,
where it is amplified and mixed to produce a 45-MHz IF signal.
An internal or external reference oscillator furnishes the reference for the synthesizer. The
VCO output is routed to mixer Ul on the RF assembly. For a description of the synthesizer
and VCO, refer to Paragraph 6.3, Synthesizer and VCO Block-Diagram Description.
IF amplifiers Q5 and Q6 amplify the first IF signal and make up any losses caused by the
insertion loss of the IF filters. FM detector chip U2 is the second mixer and quadrature
detector for the receiver. Its output includes the recovered audio and a signal-strength
indicator which are passed to the audio and squelch circuitry.
Print Date: 12/05/96
Copyright
© 1996
Glenayre
Page:
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