Pumpkin UM-20, Руководство пользователя

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User Manual
6 UM-20 Low-cost Oven-controlled Crystal Oscillator (OCXO) Assembly
Purpose
This manual describes the design and performance of a small and
inexpensive oven-controlled crystal oscillator (OCXO).
Personnel
Andrew Kalman (AEK) purchased the frequency counters and
replacement oscillators for Pumpkin, collected information on a
new OCXO design, conferred on nuances of oscillator circuits, and
tested and characterized the OCXO.
David Wright (DJW) reverse-engineered the XL Microwave
OCXO module, created the schematics and PCB for the OCXO
module
Introduction
Like many hardware developers, Pumpkin utilizes various
laboratory instruments as part of hardware development and
experimentation. Frequency counters, waveform generators,
spectrum analyzers, time interval counters and other instruments
need accurate and stable oscillators.
An external frequency reference – like a 10.000000MHz signal
from a GPS-disciplined oscillator
1
– is a popular and relatively
inexpensive, stable and accurate frequency reference to distribute
within a laboratory, for use as an external frequency standard for
compatible instruments.
Figure 1: GPS time and frequency reference receiver
1
E.g. the HP Z3805A GPS time and frequency reference receiver. This unit was
often used in cellular towers; these units were often sold on eBay once their
stated performance had expired. Upon first power-up and without a connected
GPS antenna, it was possible to identify the location of the cell tower where
the unit was located; the ones Pumpkin purchased were all from Chinese cell
towers.