The ubiquitous PLO "brick" manufactured by
Continental Microwave. Similar types available from several other
manufacturers.
The output frequency is derived by a combination of synthesis
and multiplication. A low-noise coaxial cavity oscillator operating at
frequencies in the range from 1-2GHz is phase locked using a sampling phase
detector. The phase detector is driven by the reference input frequency
which is in the range of 70-125MHz. The final output frequency results
from direct multiplaction using an SRD and narrow band filter.
A range of output frequencies are available from approximately
7GHz to 11GHz. The lock range (frequency over which operation is possible)
for a typical unit is 500MHz, e.g. 9.0-9.5GHz.
The design of these sources is optimised to take advantage of
the very best active devices and design technology available during the mid
1980's. While technology has advanced, these sources are still capable of
providing excellent signal purity and highly reliable operation in a small and
robust package. They were manufactured in considerable numbers for use in
both military and commercial microwave systems.
