Special Modes
Giga-tronics 2500B Series Microwave Signal Generators
Page 74
Operation Manual, Part Number 34737, Rev C, June 30, 2011
6.3
Use the External Reference Input
Internally, the 2500B generates a 100 MHz reference signal for the instrument. This reference signal is normally phase-
locked to a high-stability internal 10 MHz signal.
However, if an external 10 MHz or 100 MHz signal is connected to the rear EXT REF IN connector, the internal 100 MHz
reference signal phase-locks to this external signal. When an external signal is connected to the EXT REF IN connector,
the instrument detects and automatically routes it through the instrument.
Required Equipment
External signal reference (see Table 39 on page 88 for reference specifications)
Cables and connectors to connect the equipment
NOTE 1:
The example procedure in this section uses specific parameters to illustrate how to setup the 2500B. You can
use this procedure for real-life situations by simply changing the parameters to fit your needs.
NOTE 2:
If the external reference has excessive noise or drift, this will degrade the performance of the 2500B.
The procedure below describes how to use the EXT REF IN connector on the rear of the 2500B.
Table 30: Use an External Frequency Reference
Use an External Frequency Reference
Step
Action
1.
Verify that the RF output is NOT energized by checking the RF on/off indicator on the front of the
2500B (see Figure 3 on page 11). If the indicator is lit, press the
button to de-energize
the RF output.
2.
Energize the external frequency reference and let it warm up according to the manufacturer’s
recommendations.
NOTE 4:
Observe Notes 1 and 2 above regarding the integrity and specifications of the reference
signal.
3.
On the rear of the 2500B, locate the EXT REF IN connector (see Figure 6 on page 19).
4.
Connect the external frequency reference to the EXT REF IN connector on the rear of the 2500B.
NOTE:
The Ext Ref indicator on the front panel (see Figure 3 on page 11) illuminates when an
energized, appropriate external frequency reference is connected to the EXT REF IN connector.
5.
Proceed to use the 2500B as you normally would.
End of Procedure
.
RF ON
