Nautel XR6 Preinstallation Manual

Nautel XR6 Preinstallation Manual Manual pdf 57 page image

XR6/XR3 Pre-installation Manual Other considerationsIssue 3.0 2009-07-15 Page 7-1Section 7: Other considerationsThis section describes other considerations regarding the XR6/XR3 transmitter.• External RF drive source• External 10 MHz frequency reference - see page 7-2External RF drive sourceYou can apply an externally generated RF drive (carrier frequency only) to the remote interfaceboard’s digital EXT RF IN BNC connector (J6). This replaces the internal carrier frequency oscillatorfor one or both exciters (A/B).The external RF drive must:• be the carrier frequency (ƒc), within ± 5 Hz or 5 parts per million (ppm), whichever isgreater, when it is not being modulated.• have a peak-to-peak amplitude of between 5.0 V and 12 V (sine wave or square wave).• be spectrally pure when it is not being modulated.Note: There is only one external RF drive input. If you use it for both exciters,duplicate the RF drive source (main/standby), and incorporate an automaticchangeover circuit to select the standby source if the main source fails.Note: Any signal connected to the EXT RF IN input may affect the transmitter’s RFoutput. To comply with regulatory limits on emissions, ensure that the RF drivesource is acceptable.