NF WAVE FACTORY WF1967, Instruction Manual (Operations

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10.1 Purpose of Using External Frequency Reference
WF1967/WF1968 10-2
10.1 Purpose of Using External Frequency Reference
This product uses a built-in crystal oscillator as the frequency reference, but you can also use the external
10 MHz clock as the frequency reference.
Generally, the external frequency reference is used for the following purposes:
•
Use the higher accuracy of the frequency reference (for example, a rubidium frequency standard)
than that of the frequency reference built in this product to improve the accuracy and stability of the
frequency.
• Use the common frequency reference with other units to share the common frequency accuracy.
• Synchronize with other WF1967 or WF1968. For this synchronous operation of multiple units,
☞
P.9-2
10.2 Connection and Usage Procedure of External Frequency
Reference

To connect 10MHz signal
Connect the external 10MHz signal to the external 10MHz frequency reference input (10MHz REF
IN) BNC terminal on the rear panel.
WF1967 WF1968
Input characteristics are as follows:
Input voltage 0.5Vp-p to 5Vp-p
Maximum allowable input 10Vp-p
Input impedance
1kΩ, AC coupling
Input frequency 10MHz (± 5ppm(± 50Hz))
Input waveform Sine or square wave (50±5% duty)
Signal GND
Insulated from the enclosure and each channel waveform output (maximum
42Vpk)
If reflection is problem, use the terminating resistor since the input impedance is not 50Ω.
The signal ground of the external 10 MHz frequency reference input is insulated from the enclosure.
Therefore, noise caused by ground-loop does not affect the connection with a frequency standard.
Nor does noise caused by ground-loop affect the connection even when synchronously connecting
multiple units of WF1967 and WF1968.
Note that, in all cases, the floating voltage should be limited to 42Vpk (DC + AC peak) or lower to
prevent electric shocks.
For the caution for the floating ground connection,
☞
"
3.3
Cautions on Floating Ground
Connection".
10MHz
10MHz