User's Guide

3-2 Enhanced AM/FM Synthesizer Instruction Manual OS(R/T)-3(A/H) 29 - 935 MHz
The corresponding internal synthesizer jumper settings are:
Digital Board
• Jumper JU2 not installed 9.6 MHz internal frequency reference selected
• Jumper JU1 installed AM Multichannel mode selected
Analog Board
• Jumper JU1: 'B' position Internal frequency reference selected
• Jumper JU2 not installed Internal frequency reference selected
3.5 OS(R/T)-3(A/H) Synthesizer Alignment
3.5.1 General
Under normal circumstances (i.e. a change in operating frequency within the synthesizer’s
maximum tuning range), synthesizer alignment is accomplished with the synthesizer installed
in
the MT-3 Receiver IF/Audio Board or the MT-3 Transmitter Main Board. The alignment
procedure involves setting the internal TCXO reference frequency (if one is installed and the
internal reference option is enabled). This step is described in
"Reference Frequency
Alignment", section 3.5.5.5.
A change in operating frequency from the initial factory setting that
exceeds the synthesizer’s maximum tuning range (
Refer to Specifications section 1.3) requires a
more involved
alignment procedure as described in sections 3.5.2 to 3.5.5. Conversion of a
synthesizer from internal reference to external reference or vice-versa is accomplished through
selection of jumper JU1 A or B, as appropriate and JU2
(Refer to section 3.5.6).
3.5.2 Synthesizer Test Points
Analog Board Component Layout (Top)
Common to all synthesizer family members.
TP1 +8.0 ±0.3 Vdc
. U6 positive regulator output.
TP2 +5.0 ±0.1 Vdc
. U7 positive regulator output.
TP3 +5.0 ±0.1 Vdc
. U8 positive regulator output (always on).
TP4 PLL error voltage. Normal range is +0.5 to +4.5 Vdc (depending on frequency)
.
Nominally adjusted for +2.3 Vdc (via C24) for center channel
. UHF/VHF
versions employing integrated VCO modules (OSR-3H440, OST-3H418,
OST-3H460, OSR-3A149, OST-3A128, OST-3H932) require no adjustment.
Digital Board Component Layout (Bottom)
TP1 +5.0 ±0.1 Vdc
. U2 positive regulator output (controlled via pin P2-4).
TP2 Microcontroller E clock. 2 MHz logic level square wave.