Daniels Electronics Ltd. OSR-3H061 User manual

ENHANCED FM
SYNTHESIZER
INSTRUCTION MANUAL
29-470MHZ
Covers Models:
OSR-3H061 OST-3H035
OSR-3H141 OST-3H045
OSR-3H162 OST-3H141
OSR-3H440 OST-3H162
OST-3H440
Copyright
©
2006 Daniels Electronics Ltd. All rights reserved. No part
© 2006 Daniels Electronics Ltd. All rights reserved. No part ©
of this publication may be reproduced, stored in a retrieval system
or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, without the prior written consent
of Daniels Electronics Ltd.
DE™ is a registered trademark of Daniels Electronics Ltd. registered in
the U.S. Patent and Trademark Offi ce.
Document Number:
Revision:
Revision Date:
Daniels Electronics Ltd.
Victoria, BC
PRINTED IN CANADA
IM10-OS3AH
5-4-0
Apr 2006

Enhanced FM Synthesizer Instruction Manual
IM10-OS3AH
ii
This document has been produced, verifi ed and controlled in
accordance with Daniels Electronics’ Quality Management System
requirements.
Please report any errors or problems to Daniels Electronics’ Customer
Service Department.
The user’s authority to operate this equipment could be revoked through
any changes or modifi cations not expressly approved by Daniels
Electronics Ltd.
The design of this equipment is subject to change due to continuous
development. This equipment may incorporate minor changes in detail
from the information contained in this manual.
DOCUMENT CONTROL
NOTE
Daniels Electronics Ltd. utilizes a three-level revision system. This
system enables Daniels to identify the signifi cance of a revision.
Each element of the revision number signifi es the scope of change as
described in the diagram below.
DOCUMENT REVISION
DEFINITION
Major Revisions: The result of a major
change to product function, process or
requirements.
Minor Revisions: The result of a
minor change to product, process or
requirements.
Editorial Revisions: The result of typing
corrections or changes in formatting,
grammar or wording.
1-0-0
1-0-0
1-0-0
1-0-0
1-0-0
Three-level revision numbers start at 1-0-0 for the fi rst release. The
appropriate element of the revision number is incremented by 1 for each
subsequent revision, causing any digits to the right to be reset to 0.
For example:
If the current revision = 2-1-1 Then the next major revision = 3-0-0
If the current revision = 4-3-1 Then the next minor revision = 4-4-0
If the current revision = 3-2-2 Then the next editorial revision = 3-2-3
The complete revision history is provided at the back of the document.

Enhanced FM Synthesizer Instruction Manual
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Contents
Manual Section Locator
.........................................................
Manual Section Locator .........................................................Manual Section Locator
1
29-71.4MHz
Enhanced FM Synthesizer
................................
Enhanced FM Synthesizer ................................ Enhanced FM Synthesizer
3
General
Information
..................................................................................
5
Theory
of Operation
..................................................................................
7
Synthesizer
Alignment
............................................................................
1
1
Schematics
a
nd
Illustrations
....................................................................
1
5
Parts
List
..................................................................................................
2
3
128-174MHz
Enhanced FM Synthesizer
.............................
Enhanced FM Synthesizer .............................Enhanced FM Synthesizer
3
1
General
Information
.................................................................................
3
3
Theory
of Operation
.................................................................................
3
5
Synthesizer
Alignment
.............................................................................
3
9
Schematics
a
nd
Illustrations
....................................................................
4
3
Parts
List
..................................................................................................
5
1
406-470MHz-
Enhanced Synthesizer
..................................
5
9
General
Information
.................................................................................
6
1
Theory
of Operation
.................................................................................
6
3
Synthesizer
Alignment
.............................................................................
6
7
Schematics
and Illustrations
....................................................................
7
1
Parts
Lists
................................................................................................
7
9
Revision
History
...................................................................
8
7

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Enhanced FM Synthesizer Instruction Manual
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MANUAL SECTION LOCATOR
To help determine the correct section for the synthesizer in question, refer to this chart.
It is important to establish the correct synthesizer model number, as documentation is model-specifi c.
The model number can be found on the synthesizer label, located on the synthesizer module top cover.
Transmitters
Receivers
Radio
Frequency
Transmitter
Model &
Frequency
Range
Enhanced
Synthesizer
Model &
Synthesizer
Frequency
Location
in
Manual
Receiver
Model &
Frequency
Range
Enhanced
Synthesizer
Model &
Synthesizer
Frequency
Location
in
Manual
VHF Low Band
29-50MHz
VT-3H035
29-38MHz
OST-3H035
29-38MHz
See Page 3
Enhanced FM
Synthesizer
OS(R/T)-3H
29-71.4MHz
VR-3H035
29-38MHz
OSR-3H061
50.4-71.4MHz
See Page 3
Enhanced FM
Synthesizer
OS(R/T)-3H
29-71.4MHz
VT-3H045
38-50MHz
OST-3H045
38-50MHz
VR-3H045
38-50MHz
VHF
132-174MHz
VT-3/140
132-150MHz
OST-3H141
132-150MHz
See Page 31
Enhanced FM
Synthesizer
OS(R/T)-3H
128.6-174MHz
VR-3H140
132-150MHz
OSR-3H162
153.4-171.4MHz
See Page 31
Enhanced FM
Synthesizer
OS(R/T)-3H
128.6-174MHz
VT-3/160
150-174MHz
OST-3H162
150-174MHz
VR-3H160
150-174MHz
OSR-3H141
128.6-152.6MHz
UHF
406-470MHz
UT-3/420
406-430MHz
OST-3H418
406-430MHz
See Page 59
Enhanced FM
Synthesizer
OS(R/T)-3H
406-470MHz
UR-3H420
406-430MHz
OSR-3H440
427.4-451.4MHz
See Page 59
Enhanced FM
Synthesizer
OS(R/T)-3H
406-470MHz
UT-3/460
450-470MHz
OST-3H460
450-470MHz
UR-3H460
450-470MHz
Note that the operating frequency of the synthesizers in receivers is different from the receive frequency
of the radio itself. This is due to the 21.4MHz IF Offset correction factor, and is described in each section.

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Enhanced FM Synthesizer Instruction Manual
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Transmitters
Receivers
Radio
Frequency
Transmitter
Model &
Frequency
Range
Enhanced
Synthesizer
Model &
Synthesizer
Frequency
Location
in
Manual
Receiver
Model &
Frequency
Range
Enhanced
Synthesizer
Model &
Synthesizer
Frequency
Location
in
Manual
VHF Low Band
29-50MHz
VT-3H035
29-38MHz
OST-3H035
29-38MHz
Enhanced FM
Synthesizer
OS(R/T)-3H
29-71.4MHz
VR-3H035
29-38MHz
OSR-3H061
50.4-71.4MHz
Enhanced FM
Synthesizer
OS(R/T)-3H
29-71.4MHz
VT-3H045
38-50MHz
OST-3H045
38-50MHz
VR-3H045
38-50MHz
VHF
132-174MHz
VT-3/140
132-150MHz
OST-3H141
132-150MHz
See Page 31
Enhanced FM
Synthesizer
OS(R/T)-3H
128.6-174MHz
VR-3H140
132-150MHz
OSR-3H162
153.4-171.4MHz
See Page 31
Enhanced FM
Synthesizer
OS(R/T)-3H
128.6-174MHz
VT-3/160
150-174MHz
OST-3H162
150-174MHz
VR-3H160
150-174MHz
OSR-3H141
128.6-152.6MHz
UHF
406-470MHz
UT-3/420
406-430MHz
OST-3H418
406-430MHz
See Page 59
Enhanced FM
Synthesizer
OS(R/T)-3H
406-470MHz
UR-3H420
406-430MHz
OSR-3H440
427.4-451.4MHz
See Page 59
Enhanced FM
Synthesizer
OS(R/T)-3H
406-470MHz
UT-3/460
450-470MHz
OST-3H460
450-470MHz
UR-3H460
450-470MHz
29-71.4MHZ ENHANCED FM SYNTHESIZER
Covers Models:
OST-3H035
OST-3H045
OSR-3H061

Enhanced FM Synthesizer Instruction Manual
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INTRODUCTION
The OS(R/T)-3H Synthesizer is a compact, fully
shielded and environmentally rugged frequency
synthesis module that is the nucleus of every
MT-3 synthesized Receiver and Transmitter
radio module. The OS(R/T)-3H generates a high
stability, low distortion radio frequency signal in
one of several frequency bands. The OS(R/T)-3H
utilizes an internal temperature compensated
9.6 or 10.0MHz reference to produce a signal
stable to ±1 ppm within the temperature range
of -40°C to +60°C. Alternately, the OS(R/T)-
3H can be disciplined by an external 9.6MHz
or 10MHz reference of higher stability. All
synthesizer modules are designed to be easily
removed for programming, calibration and/or
repair. The synthesizer circuitry is distributed
between two printed circuit boards (PCBs)
which are isolated yet interconnected via
photo-logic optical transceivers that effectively
eliminate residual electrical noise between
digital and analog circuitry. Further shielding
of the synthesizer’s RF fi lter circuitry is
provided by an internal shielded enclosure.
GENERAL
INFORMATION
OS(R/T)-3H ENHANCED
SYNTHESIZER FAMILY
MODELS
The OS(R/T)-3H Synthesizer Module is utilized
in both the MT-3 Receiver and Transmitter
product lines. In MT-3 Transmitters, the
OS(R/T)-3H synthesizer provides a modulated,
low-level RF signal to the Power Amplifi er
module. In MT-3 Receivers, the OS(R/T)-3H
synthesizer provides a low noise local oscillator
(LO) signal that either directly drives the mixer
circuitry or fi rst drives a buffer amplifi er which
precedes the mixer circuitry (if a higher LO drive
signal is required for enhanced intermodulation
capability).
All OS(R/T)-3H FM Enhanced Synthesizer
Modules, regardless of the frequency band,
use the same digital PCB and mechanical
construction. There are, however, signifi cant
differences between the various models when
it comes to the analog PCB. Each model’s
specifi c sub-band of operation within a given
frequency band is determined through SELECT
components on the corresponding analog board.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - General Information
6
PERFORMANCE SPECIFICATIONS
Type:
Narrow band FM, Single loop synthesizer module utilizing
low noise VCO and PLL technology. Compatible with
Daniels’ MT-3 Series Transmitter and Receiver modules.
Frequency Range (Tuning range with no
adjustment is shown in [ ] brackets.):
29MHz-38MHz [±0.5MHz] (OST-3H035)
38MHz-50MHz [±1.0MHz] (OST-3H045)
50.4MHz-71.4MHz [±1.0MHz] (OSR-3H061)
Output Power:
+5dBm ±2dBm into 50 Ω
Harmonics:
<-30 dBc
Spurious:
<-90 dBc
Hum and Noise:
>55 dB
Modulation Sensitivity:
3.0kHz peak deviation (400mVrms input)
External Reference Input:
External reference input signal via SMB connector J1
Input level 0dBm ±3 dB
Input impedance 50
Input frequency 10.0MHz or 9.6MHz
selectable through digital board jumper JU1
Power Requirements:
Normal Confi guration: +9.5VDC @ 160mA
Low Current Standby Mode (TCXO enabled): +9.5VDC @ 14mA

Enhanced FM Synthesizer Instruction Manual
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7
THEORY
OF OPERATION
THEORY OF OPERATION
Internal Power and Control (Digital Board)
The synthesizer operates from a +9.5VDC
power source applied to connector pin P1-2.
Total current draw is approximately 160mA.
POWER DOWN control line P2-4 controls
the +5.0VDC microcontroller regulator U2
through power MOSFET switch U1. For
receiver applications the synthesizer is
always ON, with the enable line P2-4 directly
connected to +9.5VDC. For transmitter
applications, pin P2-4 is controlled by the
MT-3 Transmitter Board jumper J18 which
selects the synthesizer standby mode. In
Low Current Standby Mode, less than 14mA
is drawn, however, a delay of approximately
50ms from PTT activation to transmitter turn
on is then required to allow for the synthesizer
to lock. In Normal Mode, with the synthesizer
ON continuously, less than 10ms delay is
encountered. This capability comes at the
expense of additional standby current (160mA).
Synthesizer Analog Circuitry (Analog Board)
The Analog Board utilizes four optical receivers
(U1–U4) and one optical transmitter (U5)
to provide an isolated data interface to the
digital board. The regulator IC U8 provides
a continuous +5.0VDC to the internal TCXO
and power control optical receiver U1 when
ever +9.5VDC is applied to the synthesizer’s
voltage terminals. The analog board’s main
power is turned on and off by driving the optical
receiver U1. U1 is driven by U4 on the digital
board, which is controlled by the microcontroller.
The main power regulators are provided by
U6 and U7. Regulator U6 provides switched
+8.0VDC and regulator U7 proves switched
+5.0VDC. The power MOSFET IC U9 works
as a clamping circuit to quickly discharge the
VCO fi lter capacitors C32 and C33; when
U9 is powered down the RF output from the
VCO is suppressed almost immediately.
At the heart of the OS(R/T)-3H Enhanced
Synthesizer is U10 a low power, single chip
PLL synthesizer IC. U10 is setup to use a 9.6
or 10.0MHz reference signal provided either
from the internal TCXO (with JU1-B selected)
or from the external SMB connector J1 (with
JU1-A selected). The reference signal’s
frequency is selected by jumper JU2 on the
digital board; 9.6MHz is selected if JU2 is
not installed and 10MHz if JU2 is installed. If
an external reference signal is used it must
be sinusoidal, low phase noise, and highly
stable with an output power of 0dBm ±3dBm.
A poor quality reference source will degrade
the receiver or transmitter performance to
unacceptable levels. The external reference
is buffered by transistor Q2 on the analog
board, which has 50Ω input impedance at
10.0MHz. The internal TCXO reference of
10.0MHz provides better than ±1ppm frequency
stability from -30°C to +60°C (-40°C to +60°C
optional). The TCXO fi ne frequency adjustment
is made through potentiometer RV1, which is
accessible through the synthesizer’s top cover.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - Theory of Operation
8
The fi eld effect transistor Q5 forms part of the
negative resistance VHF amplifi er oscillator that
is tuned on-frequency by the combination of the
resonator L5 and the total capacitive reactance
presented across L5 through capacitors C62,
C63, C64, C23 (Select), variable capacitor C24,
and varactor diodes D1 and D2. Fine frequency
adjustment is obtained via the multi-turn trimmer
capacitor C24 in conjunction with the coarse
frequency jumper selections JU2, JU3 and
JU4. Select capacitor values are chosen to
position the operating frequency in one of three
bands: 29-38MHz, 38-50MHz or 50.4-71.4MHz.
Varactor diodes D1 and D2 provide oscillator
frequency control. The PLL control voltage,
at the output of the low-pass loop fi lter (TP4),
controls the VCO frequency through the reverse
biasing of varactor diodes D1 and D2. The PLL
control voltage can range between ≈ +0.5VDC
and +4.5VDC and is nominally set to ≈ +2.3VDC
at the synthesizer centre frequency. Setting
of the PLL control voltage test point (TP4) is
achieved by adjusting fi ne frequency variable
capacitor C24 combined with binary weighted
lumped capacitor coarse frequency jumpers
(JU2, JU3, JU4). External baseband frequency
modulation is provided through connection
P1 and a voltage divider network formed by
R21 and R22. A large signal division ratio,
established by the resistive dividers R21 and
R22, allows low deviation (less than 5kHz) direct
frequency modulation of the VCO output signal.
The PLL low-pass fi lter is formed by SELECT
components C37, C38, C39, C45, R32 and
R36. The loop fi lter response is optimized
for switching time, noise and modulation
requirements specifi c to each sub-band within
the 29-71.4MHz frequency range. The SELECT
components (including the loop fi lter) can be
found in tabular format on the VHF OS(R/T)-3H
29-71.4MHz Analog Board Schematic diagram.
RF output power is taken from the source
of Q5 and amplifi ed/buffered by U11. U15
provides further amplifi cation and isolation
while delivering approximately +10dBm into a
six-pole low-pass notch formed by C53, C57,
C58, C59, L11 and L13. The six pole output
fi lter, with a cutoff frequency of 50MHz for
models OST-3H035 and OST-3H045 or 80MHz
for the OSR-3H061 effectively eliminates
output harmonics. SMB connector J2 provides
interconnection to the companion transmitter or
receiver with an output level of +5dBm ±2dBm.
The 9.6 or 10.0MHz reference source is divided
down to establish a channel selection step
size of 5.0 or 6.25kHz. A third order passive
loop fi lter comprised of C37, C38, C39, C45,
C49, R36 and R32 are employed to achieve
the required noise performance, modulation
and worst case switching time of 50ms. A small
sample of RF energy is coupled from the VCO
output buffer U16 to the synthesizer IC U10
prescaler input (pin 11). FM modulation of
the VCO from approximately 100Hz to 3kHz
is achieved through the baseband input pin
P1-1 on the Digital Board. A 1kHz sine wave
with a level of approximately 400mVrms at
P1-1 provides FM deviation of 3.0kHz. SMB
connector J2 provides an RF output level
of approximately +5dBm into a 50Ω load.
An optional low frequency modulation input
is provided through connector P1-18 on the
digital board, and routed to the analog board via
connector P3. This modulation input is coupled
to a low impedance DC coupled source. The
input provides a phase modulated bandwidth
from 0Hz (DC) to the PLL loop fi lter bandwidth.
This allows for specialized applications such
as paging or trunking where a separate low
frequency digital/analog modulation channel is
required. The phase modulation input on the
digital board, connector P1-18, is routed to the
transmitter’s audio processor pin P4-2 via JA4-2
on the MT-3 transmitter’s main board. It should
be noted that any application that uses the direct
TCXO modulation port transfers control of the
synthesizer’s steady state frequency setting to
the external modulation source. The internal
TCXO frequency control potentiometer RV1 is
then effectively removed from the circuitry.
A lock detect LED on the synthesizer’s analog
board (LED1) indicates an unlocked PLL
condition. An unlocked PLL condition normally
indicates that the VCO is not tuned within the
lock in range of the desired channel frequency.
In a transmitter, the loss of lock will prevent a
PTT from keying the power amplifi er module,
thus preventing the transmission of a spurious
output signal. Adjusting capacitor C24 will
normally re-establish a frequency lock within
the synthesizer’s frequency range. The optical
transmitter U5 on the analog board is also
activated in an unlocked condition and enables
the micro controller on the digital board to
respond to the unlocked PLL condition.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - Theory of Operation
9
Synthesizer Digital Circuitry (Digital Board)
The synthesizer’s digital board circuitry
generates control signals utilized within the
synthesizer. The microcontroller U4 on the digital
board: communicates with the synthesizer’s
PLL IC U10 on the analog board; monitors
the synthesizer lock detect; manages the PTT
input and output; and determines the operating
frequency by reading the channel code number
information from either the four rotary binary
coded decimal (BCD) switches mounted on
the transmitter or receiver’s main board, or by
reading the four externally driven channel select
lines. The microcontroller U4 is also designed
to communicate with Daniels’ Synthesizer
Channel Programmer (CP-SC-3) through I/O
lines TX Data (P1-17), RX Data (P1-9) and
Bootstrap (P2-2). This external programmer
places the operating program in non-volatile
microprocessor memory and programs up
to 15 user defi ned channel code numbers.
An internal “watchdog” timer provides robust
software protection in all operating modes.
Data communication between the digital and
analog circuit boards is achieved through
four optical transmitters (U5 through U8)
and one optical receiver (U9). The optical
interface provides a fully isolated inter-
board data communications link designed
to prevent digital noise from interfering
with the sensitive PLL circuitry.
BCD Switch Frequency Control
Selection of the desired synthesizer output
frequency is straightforward. If all four of the
CHANNEL SELECT lines (CHAN SEL3-CHAN
SEL0) are pulled low (to GND), the synthesizer
will scan the four BCD switches (FSW1- FSW4)
located on the receiver or transmitter main
boards via connections SW1 COM-SW4 COM
and PC4-PC7 and establish the operating
frequency from these switches. The four
CHANNEL SELECT lines, CHAN SEL3-CHAN
SEL0, are connected via the MT-3 transmitter
or receiver main board module connector to the
M3 motherboard subrack. These lines are by
default normally pulled low (to GND) via jumpers
located on the M3 motherboard subrack.
If any one of the CHANNEL SELECT lines are
pulled high (to +9.5VDC), then the synthesizer’s
frequency of operation will be determined
by the CHANNEL SELECT lines and not the
BCD switches. Up to 15 separate channel
frequencies can be pre-programmed into a
‘table’ in non-volatile microprocessor memory
and accessed through binary interpretation
of the CHANNEL SELECT lines. The most
signifi cant bit (MSB) in the CHANNEL SELECT
binary code is represented by CHAN SEL3 and
the least signifi cant bit (LSB) is represented
by CHAN SEL0. For example, if all CHANNEL
SELECT lines are pulled high, (i.e. binary
‘1111’) then the 15th frequency entry in the
internal channel table will be selected. The
channel table is normally pre-programmed
at the factory to user specifi cations, but may
be programmed in the fi eld using Daniels’
Synthesizer Channel Programmer (CP-SC-3).
In transmitters, the synthesizer operating
frequency is the transmitter operating
frequency. For receivers the synthesizer’s
operating frequency is 21.4MHz above the
receiver frequency. Refer to the Channel
Designation Table Manual for a channel
code number versus frequency table.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - Theory of Operation
10
Synthesizer Base and Frequency Increments
The OS(R/T)-3H Synthesizer operates in frequency increments of 5.0/6.25kHz. The Base
Frequency for any given synthesizer model is the lowest frequency generated.
Model Number Freq. Range Base Freq. Freq. Increment
Model Number Freq. Range Base Freq. Freq. Increment
OST-3H035 29-38MHz 29MHz 5.0/6.25kHz
OST-3H045 38-50MHz 29MHz 5.0/6.25kHz
OSR-3H061 50.4-71.4MHz 50.4MHz 5.0/6.25kHz
5.0/6.25kHz Channelization
The OS(R/T)-3H synthesizers have been designed to generate frequencies in both 5.0 kHz
and 6.25 kHz channel increments. The frequency increments are determined by the channel
code number range. The channel code numbers from 0000 to 4999 increment the frequency
in 5.0 kHz increments, and channel code numbers from 5000 to 9999 increment the frequency
by 6.25 kHz increments. The channel code number is either stored in the synthesizer’s
memory or by the BCD switches on the transmitter or receiver’s main board. The channel
number determines where the channel code number is retrieved from; channel 1 is stored by
the BCD switches, and channels 2 through 16 are stored in the synthesizer’s memory.
To calculate the operating frequency for the OS(R/T)-3H from the channel code
numbers refer to the Channel Table Instruction Manual or the calculations below.
BCD switch settings from 0000 to 4999
:
Multiply the switch setting by 5.0kHz and add the result to the synthesizer base frequency.
Example: An OST-3H045 synthesizer has a base frequency of 29MHz. The selected channel
number is 0988. The
synthesizer
synthesizer
output frequency is: ((988 x 5kHz) +29MHz) = 33.940MHz
output frequency is: ((988 x 5kHz) +29MHz) = 33.940MHz
synthesizer output frequency is: ((988 x 5kHz) +29MHz) = 33.940MHzsynthesizer
synthesizer output frequency is: ((988 x 5kHz) +29MHz) = 33.940MHzsynthesizer
BCD switch settings from 5000 to 9999
:
Subtract 5000 from the switch setting. Multiply the result by 6.25kHz
and add the result to the synthesizer base frequency.
Example: An OST-3H035 synthesizer has a base frequency of 29MHz. The selected channel number
is 7205. The
synthesizer
synthesizer
output frequency is: (((7205-5000) x 6.25kHz) +29MHz) = 42.78125MHz
output frequency is: (((7205-5000) x 6.25kHz) +29MHz) = 42.78125MHz

Enhanced FM Synthesizer Instruction Manual
IM10-OS3AH
11
GENERAL
OS(R/T)-3H enhanced synthesizer alignment is
simplifi ed by using a Type 84 subrack and RF
extender card/cable for providing receiver or
transmitter power and signal interconnection.
Alternately, a +9.5VDC may be directly
connected to a receiver or transmitter module
with the positive connection on pins B6/Z6
and the negative connection on pins B30/
Z30/B32/Z32. The receiver’s balanced audio
output (600Ω) is available at pins B26 and
Z26. The transmitter’s balanced audio output
(600Ω) is available at pins B18 and Z18.
REPAIR NOTE
The OS(R/T)-3H synthesizer employs a
large number of surface mount components.
Removal and/or replacement of surface
mount components should never be
performed using an ordinary soldering iron but
should only be performed at surface mount
rework and repair stations equipped with
Electrostatic Discharge (ESD) protection.
When removing Surface Mount Solder
Jumpers, it is recommended that a solder
wick braid be used in lieu of vacuum
type de-soldering tools to help prevent
damage to the printed circuit boards.
SYNTHESIZER
ALIGNMENT
RECOMMENDED TEST
EQUIPMENT
Synthesizer alignment requires the following
test equipment, or its equivalent:
Power supply-Regulated +9.5VDC
at 2 A. Phillips PM 2811
at 2 A. Phillips PM 2811
Oscilloscope/Multimeter-Fluke 97 Scopemeter
Oscilloscope/Multimeter-Fluke 97 Scopemeter
Radio communications test set-
Marconi Instruments 2965A
It is recommended that the radio
communications test set be referenced to an
external high stability frequency source (WWVH,
GPS, Loran C) so that the OS(R/T)-3H internal
high stability local oscillator may be accurately
set to within its ±1 ppm frequency tolerance.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - Synthesizer Alignment
12
OS(R/T)-3H SYNTHESIZER
FACTORY CONFIGURATION
The OS(R/T)-3H Synthesizer is factory
confi gured as follows:
Internal 9.6 or 10.0MHz reference selected.
VCO modulation (via audio processor)
enabled (OST TX versions only)
enabled (OST TX versions only)
The corresponding synthesizer
jumper settings are:
Digital Board
Jumper JU2 installed
10.0MHz reference
frequency selected (default)
frequency selected (default)
Jumper JU2 not installed
9.6MHz reference
frequency selected (default)
frequency selected (default)
Jumper JU1 not installed
AM Multichannel mode
selected (default)
selected (default)
Analog Board
Jumper JU1: ‘B’ position
Internal TCXO reference
frequency selected (default)
frequency selected (default)
OS(R/T)-3H SYNTHESIZER
ALIGNMENT PROCEDURE
General
Synthesizer alignment is normally 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,
the internal reference option is enabled. This
step is described in ‘Reference Frequency
Alignment’ in this section. A change in operating
frequency from the initial factory setting that
exceeds the synthesizer’s maximum tuning
range (Refer to Specifi cations) requires a more
involved alignment procedure as described
below. The conversion of a synthesizer
from an internal reference to an external
reference or vice-versa is accomplished
through the selection of jumper JU1 A (for
external) or B (for internal, on the analog
board), and as appropriate JU2 on the digital
board (Refer to ‘Jumper Confi guration’).
Synthesizer Test Points
Analog Board Component Layout (Top)
TP1 +8.0 ±0.3VDC
U6 positive regulator output
U6 positive regulator output
TP2 +5.0 ±0.1VDC
U7 positive regulator output
U7 positive regulator output
TP3 +5.0 ±0.1VDC
U8 positive regulator output (always on)
U8 positive regulator output (always on)
TP4 PLL error voltage.
Normal range is +0.5 to +4.5VDC
(depending on frequency).
Nominally adjusted for +2.3VDC
(via C24) for center channel
(via C24) for center channel
Digital Board Component Layout (Bottom)
TP1 +5.0 ±0.1VDC.
U2 positive regulator output
(controlled via pin P2-4)
(controlled via pin P2-4)
TP2 Microcontroller E clock.
2MHz logic level square wave
2MHz logic level square wave

Enhanced FM Synthesizer Instruction Manual
IM10-OS3AH
29 - 71.4 MHz - Synthesizer Alignment
13
Synthesizer Removal and Installation
Note: Complete synthesizer alignment can
be performed without removing the
synthesizer from the radio.
The synthesizer module is secured to the main
board (MT-3 Receiver IF/Audio Board or MT-3
Transmitter Main board) with a single counter
sunk Phillips machine screw accessible from
the top cover. Remove this screw to remove
the synthesizer module. Using a plastic
coated lifting tool, such as a small screwdriver
with the tip covered in heat shrink material,
gently lift the synthesizer module from the
main circuit board by applying pressure in a
rotating fashion about the four corners of the
synthesizer module. It is important to gently
remove the synthesizer module “straight out”
in order to prevent damage to the connector
pins. Installation of the synthesizer is performed
by fi rst ensuring complete connector pin
alignment; second appling reinsertion force;
and third securing the synthesizer to the main
board with the single countersunk phillips
machine screw. Note the four corner locating
pins on the synthesizer housing assist in
connector pin alignment during the installation.
Circuit Board Removal
Note: Circuit board removal is not required
for tuning purposes.
The analog and digital boards can be removed
using a vacuum de-soldering station. To remove
the analog board: de-solder connections P1,
P2 and P3; remove the SMB connectors J1
and J2 by de-soldering the center pins and
removing the four (2 per connector) M2 machine
screws; remove the seven M2 machine screws
(that secure the analog board) and carefully
remove the analog circuit board. Removal
of the analog circuit board will expose three
inter-board wire connections. Carefully remove
three ferrite beads and six Tefl on washers
from the inter-board connection wires. Attempt
to maintain the position of the three inter-
board wires in order to simplify re-assembly.
The digital board may now be extracted by
removing four M2 machine screws. Follow
a reverse procedure to re-assemble.
Frequency Adjustment and Channel
Selection
Connect a radio communications test set
through a short section of low loss 50Ω coaxial
cable to the synthesizer’s SMB RF output jack
(J2). Select the desired channel code number
via the BCD frequency selection switches on
the main board, or reprogram the synthesizer
memory with a Channel Synthesizer Programer
(CP-SC-3). Turn the power off and back on
and wait a few minutes for the oscillator to
completely stabilize. It should be noted that
the internal synthesizer TCXO, if installed,
operates continuously (regardless of the TX
PTT state) when installed in a transmitter.
The measured RF output signal should be
within ±1.0 ppm of the specifi ed oscillator
frequency at an output level of +5dBm ±2dBm
@ 25°C. Note that an unlocked synthesizer
operation will also be indicated by an unstable or
spurious RF output signal. The “Unlocked” red
LED will be illuminated if the PLL is unlocked.
If a VCO Alignment does not resolve the
unlocked condition, check that the requested
channel code number is within the frequency
range of the particular synthesizer model. An
unlocked condition will probably be rectifi ed
by adjusting the VCO tuning elements as
described in the following procedures.
VCO Alignment
Refer to the ‘Analog Board Component
Layout’ diagrams and on.
1) Measure the PLL DC control voltage at TP4
located on the synthesizer module analog
board (top) using a high impedence (10MΩ)
voltmeter (access to TP4 is available
through the synthesizer top cover).
2) Carefully adjust the VCO fi ne frequency
“TUNE” trimmer capacitor C24, using a
small standard blade screwdriver, until a
test point (TP4) voltage of approximately
+2.3VDC is obtained. PLL loop control
voltages below approximately +0.5VDC and
above approximately +4.5VDC will indicate
an “out of lock” synthesizer condition.

Enhanced FM Synthesizer Instruction Manual
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29 - 71.4 MHz - Synthesizer Alignment
14
If a TP4 reading of approximately +2.3VDC
is unattainable through adjustment of C24,
then the coarse frequency jumpers, JU2-JU4
require modifi cation in order to pull the VCO
tune range within the adjustment range of fi ne
tuning capacitor C24. The top synthesizer
cover must be removed in order to gain
access to the coarse frequency jumpers.
The coarse frequency jumpers (JU2-JU4)
may be considered to be a selectable binary
weighted capacitor element with JU2 being the
most signifi cant “bit” and JU4 being the least
signifi cant “bit”. The tuning resolution size is
approximately 12pF (JU4). If the tuning voltage
remains higher than +2.3VDC, decrease the
tuning jumper setting by 1 “bit” position and re-
adjust C24 in an attempt to achieve +2.3VDC at
TP4. For example, if coarse frequency jumpers
JU2-JU4 are all installed and represented by
111 then a decrease by 1 “bit” position (12pF)
is represented by a binary jumper selection of
110; jumper JU4 is not installed and jumpers
JU2, JU3 are installed. Continue to decrease
the jumper position one “bit” at a time until the
synthesizer regains lock with TP4 adjusted
(C24) for +2.3VDC. If the tuning voltage remains
lower than +2.3VDC, increase the jumper
setting by 1 “bit” position and re-adjust C24 in an
attempt to achieve +2.3VDC at TP4. Repeat this
procedure until +2.3VDC is achieved at TP4.
It is important to check the loop control voltage
at TP4 when multiple synthesizer channels have
been programmed. All channel selections should
result in a TP4 voltage within a +1.0 to +4.0VDC
range. Adjust the fi ne-tuning capacitor C24 to
center multiple channel voltages symmetrically
about +2.3VDC. Channel selections beyond
the tuning range capability of the synthesizer
will result in unlocked operation. The tuning
range capability of this synthesizer model is
listed in the Therory of Operation section.
Reference Frequency Alignment
To adjust the output frequency of the synthesizer
the reference frequency of the TCXO is
adjusted. Note this adjustment is only valid when
the internal reference is selected (JU1 in the
B position on the analog board). To adjust the
internal TCXO referency frequency adjust the
synthesizer TCXO fi ne frequency potentiometer
RV1 until the correct output frequency is
achieved. Access to this potentiometer is
through an opening in the synthesizer top cover.
An RF power level of approximately +5dBm
±2dBm should be measured at the synthesizer’s
SMB output connector J2. The frequency should
be within ±1 ppm of the desired operating
frequency. Reference frequency adjustments
should be made at room temperature (+25°C)
after a ten minute stabilization period.
JUMPER CONFIGURATION
The synthesizer’s surface mount solder
jumpers are clearly marked on both of it’s
digital and analog circuit boards. Refer
to the ‘Digital Board Component Layout
(Bottom)’ diagram in this section and the
‘Analog Board Component Layout (Top)’
diagram for jumper locations. The following
list details the required jumper confi guration
for the two synthesizer operating modes:
1) Internal reference. Install jumper JU1 in the B
position, 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
in the A position 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 the
synthesizer’s SMB connector J1. An optional
front panel external reference connector is
available as an option for transmitters and
receivers.
3) Reference Frequency Select. Install jumper
JU2 on the Digital Board to select a 10.0MHz
reference frequency. When not installed, the
reference frequency is by default 9.6MHz.
JU2 is used by the microcontroller to establish
the correct reference frequency division ratio.
(the Synthesizer module must be removed to
change jumper JU2 on the digital board.)
Note: 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..

Enhanced FM Synthesizer Instruction Manual
IM10-OS3AH
15
PRINTED CIRCUIT BOARD
NUMBERING CONVENTION
Daniels Electronics Ltd. has adopted a printed
circuit board (PCB) numbering convention in
which the last two digits of the circuit board
number represent the circuit board version. All
PCB’s manufactured by Daniels Electronics Ltd.
are identifi ed by one of the following numbering
conventions:
PCB number 43-9120
10
Indicates
circuit board version 1.0
PCB number 50002-
02
Indicates circuit board version 2
(no decimal version)
(no decimal version)
SCHEMATICS
AND ILLUSTRATIONS

Enhanced FM Synthesizer Instruction Manual
IM10-OS3AH
Schematics and Illustrations - 29-71.4 MHz FM Synthesizer
16
RF OUTPUT
EXTERNAL
CHANNEL
SELECT /
DATA
BANDPASS
FILTER
ENHANCED
BUFFER
AMPLIFIER
BUFFER
AMPLIFIER
MODULATION
INPUT
5VDC SUPPLY
&
8VDC SUPPLY
CONTROL
MICROPROCESSOR
PLL
PLL FILTER
FINE
FREQUENCY
ADJUST
DIRECT /
LOW FREQUENCY
MODULATION
INPUT
OPTIONAL
HIGH STABILITY
EXTERNAL
REFERENCE
A B
ENHANCED
BUFFER
AMPLIFIER
INTERNAL /
EXTERNAL
REFERENCE INTERNAL
FREQUENCY
REFERENCE
A
DATE: 23 SEPTEMBER 2003
TITLE: SYNTHESIZER MODULE BLOCK DIAGRAM
DRAWN BY: EVA DANIELS
REV DATE: 04 FEBRUARY 2005
DWG No: B0319-02
1
11
21
2
12
22
3
13
23
4
14
24
5
15
25
6
16
26
7
17
27
8
18
28
9
19
29
10
20
30
DANIELS
ELECTRONICS LTD
TM
SYNTHESIZER MODULE BLOCK DIAGRAM
B0319-02