Daniels Electronics Ltd. OST-3H035, Instruction Manual

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DE DANIELS
ELECTRONICS
Enhanced AM/FM Synthesizer Instruction Manual OS(R/T)-3(A/H) 29 - 470 MHz 1-1
1 GENERAL
1.1 Introduction
The OS-3A/H Synthesizer Module produces a low distortion, high stability, FM modulated (FM
transmitter) or unmodulated (receiver LO, AM transmitter) RF signal covering the frequency bands
of 29 - 50 MHz, 118 - 159.4 MHz, 118 - 174 MHz and 406 - 470 MHz. It achieves ±1 ppm
frequency stability from -40°C to +60°C with its own internal reference, or it can be slaved to an
external 10/9.6 MHz reference signal of desired stability. The OS-3H Synthesizer Module is
provided in eleven models covering three primary frequency bands (see section 1.2). A synthesizer
module can be easily removed for programming, calibration, or repair. Each synthesizer module
contains two circuit boards providing digital and analog functionality. The analog RF circuitry is
fully isolated in a shielded compartment. Three inter-board filtered wire connections provide signal
and power interface. Digital signal and power control is provided through five photo-logic optical
transceivers, further enhancing electrical noise isolation.
1.2 OS(R/T)-3(A/H) Enhanced Synthesizer Family Models
The OS-3A/H Synthesizer module family forms an integral component of the MT-3 receiver and
transmitter product line. In transmitters, the OS-3A/H synthesizer provides a modulated low level
RF signal to the Power Amplifier module. In receivers, the OS-3A/H synthesizer provides a low
noise local oscillator signal that either directly drives the mixer circuitry or drives a buffer amplifier
in order to achieve higher LO mixer drive required for enhanced intermodulation capability. There
are eleven distinct models in the OS-3H Enhanced Synthesizer Family. Note that this manual
provides service and operating information for all eleven synthesizer family members. It is
important to establish the correct synthesizer model number of interest in order to direct attention to
specific documented information. The specific model number is printed on the synthesizer module
top cover.
The eleven models are described as follows:
Frequency Band: 29 - 50 MHz, Common OS-3H0xx Analog Board
• OST-3H035 - synthesized, installed in transmitter, 29 - 38 MHz RF output.
• OST-3H045 - synthesized, installed in transmitter, 38 - 50 MHz RF output.
• OSR-3H061 - synthesized, installed in receiver, 50.4 - 71.4 MHz RF output.