104 XLi IEEE 1588 Clock
997-01510-03, Rev. C, 12/12/2006
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Setting the J2 Output Configuration
To set the J2 Output Configuration, send a character string with the previously defined F111 entry format
to the Serial/Network port. Only valid values are accepted. The J2 Output Configuration can be set to
specify one of several predetermined rates. The following sections provide examples (and some
explanations) for each.
Predetermined RATE output
For example, to produce a fixed 100 kPPS rate output, enter:
F111 RATE 100KPPS<CR>
The XLi responds:
OK<CR><LF>
F113 – J3 Input Configuration (Aux Ref)
Note: Freq Meas is currently unavailable as an option for the standard XLi IEEE 1588 clock. Most of the
Freq Meas related information has been removed from this section.
Use function F113 to configure the J3 Input for one of the following settings:
• Auxiliary Reference (Aux Ref) input
• Disable all J3 inputs
F113 offers the following keypad settings:
• J3 Input Configuration: Aux Ref, Freq Meas, Disabled
• J3 Input Frequency: 1 MHz, 5 MHz, 10 MHz
• J3 Input Impedance: 1kΩ, 50 Ω
The factory settings are Disabled, 10 MHz, and 1kΩ.
For J3 Input specifications, see “J3 Input – Auxiliary Reference” on page 13.
Auxiliary Reference (Aux Ref) Input:
If an external frequency reference with better long-term stability than the XLi's own oscillator—such as a
Cesium reference—is available, connect it to the J3 connector and enable Aux Ref using F113. Once
this is done, the XLi will use the Aux Ref input (rather than its own oscillator) as its frequency source if
the XLi's reference source(s) become unavailable.
For example, with a single GPS receiver card configured as PRIMARY in F119, and F74 – Clock Source
Control set to PRI,