External Reference Lock Status Messages

These messages, which appear at the bottom of the window, indicate the status of the external reference.

Message	Explanation
<blank>	External reference status message. The 89600 VSA uses the reference signal generated internally by the input module.
EXT REF	External reference status message. The 89600 VSA is locked to a signal at the external reference connector.
INT REF	External reference status message. The 89600 VSA is locked to the clock signal provided by the reference instrument.
UNLOCKED	External reference status message. The Lock Reference state for a piece of hardware that is used in conjunction with other hardware modules has been changed from True to False. Or the external reference for a piece of hardware that has Lock Reference set to True could not lock to the external reference. If Ext Reference Frequency for an 89605B or 89606B module is set to 13 MHz Megahertz: A unit of frequency equal to one million hertz or cycles per second. and a 13 MHz signal is not connected to the Ext Ref In connector, calibration will fail.