User's Guide

Enhanced AM/FM Synthesizer Instruction Manual OS(R/T)-3(A/H) 29 - 470 MHz 3-7
3.5.6 Jumper Configuration
Solder jumpers are clearly marked on both synthesizer digital and analog circuit boards. Refer to
the "OS(R/T)-3(A/H) Digital Board Component Layout (Bottom)" diagram on page 4-17 of this
manual and the a pplicable "OS(R/T)-3(A/H) Analog Board Component Layout (Top)" diagram on
page 4-18 for jumper locations . The following list details the required jumper configuration for the
two synthesizer operating modes:
1) Internal reference. Install jumper JU1-B, on the Analog Board (Standard). The internal
temperature compensated crystal oscillator (TCXO) provides the reference signal with a
stability of ±1 ppm from -30°C (Optional -40°C) to +60°C.
2) External reference input. Install jumper JU1-A and JU2 on the Analog Board. This mode is
used in applications requiring better than ±1 ppm frequency stability . An external reference
signal must be provided at synthesizer SMB connector J1.
3) Reference Frequency Select . Install jumper JU2 on the Digital Board to select a 10.0 MHz
reference frequency. When not installed, the reference frequency is by default 9.6 MHz.
JU2 must not be installed when using the internal 9.6 MHz TCXO reference . JU2 is used
by the microcontroller to establish the correct reference frequency division ratio. (Located
on the Digital Board; The Synthesizer module must be removed to change jumper JU2.)
4) AM Multichannel Synthesizer Select . Install jumper JU1 on the Digital Board to select and
enable the AM Multicha nnel Synthesizer with Frequency Select Handle.
Caution : Care must be exercised when reinstalling the synthesizer module on the Transmitter
Main board or the IF/Audio board. Pay careful attention to pin alignment before
pressing the synthesizer module into its mating sockets.