Hardware; Rf Output; Reference Input / Outputs; 10/100 Mhz External Reference - Holzworth Instrumentation HSX Series User Manual

7.0 HARDWARE

The HSX Series Multi-Channel RF Synthesizers are CW work horses. They are
designed to do a very good job of providing highly stable, phase coherent signals with
pure spectrums and highly accurate output power amplitude control.

7.1 RF OUTPUT

The RF Output ports are labeled and positioned sequentially from left to right on the
front panel of the instrument. The RF Output ports are protected against reflected
power with a maximum damage threshold of 25V (+10dBm or 10mW).
DC

7.2 REFERENCE INPUT / OUTPUTS

The reference input and output ports are
located on the right side of the rear panel.
NOTE that the internal reference distribution
subsystem must be manually set for the type
of reference being used. The factory default
setting is for the internal reference (free
running). Users can change the reference
setting using the Application GUI or by
sending ASCII commands.

7.2.1 10/100 MHz EXTERNAL REFERENCE

When a 10MHz or 100MHz External Reference signal is applied and External 10MHz or
External 100MHz is selected in software, the system enables a 20Hz digital PLL which
phase locks the internal OCXO to the external reference signal. The internal OCXO
remains operating in both scenarios to maintain optimal phase noise levels at >20Hz
offset. The performance of the synthesized channel output signals as well as the fixed
10MHz and 100MHz Reference Output signals are based on the 10 or 100MHz external
reference for offsets of <20Hz; performance is based on the integrity of the 100MHz
internal OCXO at offsets of >20Hz.
This architecture is often used in laboratories and systems as a cleanup loop for 10MHz
Rubidium, Cesium, GPS disciplined, etc. references; as it provides an optimal reference
signal for the internal channels as well as both the 10MHz and 100MHz reference
outputs.
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