226 Keysig ht N9923-90001 User’s GuideSystem SettingsSystem ConfigurationSaving Data with GPS EnabledGPS position and clock data are included when data is saved with the followingfiles types: *.csv, *.SnP, State, State+Trace data save.A warning is shown if the GPS is ON but unlocked at time of save, or if the GPSfeature is ON but no GPS is physically present at time of save.The following is a sample S1P file with GPS information:!GPS Latitude: 38 28.87717 N!GPS Longitude: 122 42.66625 W!GPS TimeStamp: 06/25/2010 16:24:48!GPS Seconds Since Last Read: 2sFrequency Reference SourceThe FieldFox internal frequency reference source is used to make accurate andstable measurements. To improve measurement accuracy and stability, youcan use a highly-stable external 10 MHz reference source.The External Reference setting will surviv e a Factory Preset or Mode Preset andis saved as part of the Instrument State. When resuming after Standby, theFieldFox will display an Unlock message while it acquires a lock to an externalor GPS source.How to use an External ReferenceConnect the 10 MHz External Reference to the EXT TRIG/EXT REF BNCconnector on the FieldFox top panel. External Triggering is NOT available onthe N9923A.— Press System 7— Then System Configuration— Then Frequency Ref— Then Freq Ref Source Int ExtWhen switched to Ext, if the FieldFox do es NOT find an appropriate signal withwhich it can lock, then Ext Ref UNLOCKED is displayed in the lower-left cornerof the screen. This can occur when any of the following conditions exist:— NO external reference signal is present.— A low-level external reference signal is present.— A very high-level external reference signal is present.The FieldFox may take up to 10 seconds to lock to a valid ExternalReference source.
