8560E IF Input / Built-in Tracking Generator Configuration Question - Page 1
Forum section: electronics / testgear

author: Electro Fan
author_rank: Super Contributor
timestamp: February 22, 2015, 05:35:24 pm
content: If a HP/Agilent 8560E has a built-in tracking generator it appears that the TG (RF Out) takes up a place on the front panel that would otherwise have had a IF Input. Is it possible that adding the TG would preclude the use of an external mixer? Or can the built-in TG and an external mixer both be used on a 8560E with the built-in TG? Thanks

author: Electro Fan
author_rank: Super Contributor
timestamp: February 22, 2015, 10:55:04 pm
content: Ok, might have found the answer - but it would be great if someone here with more knowledge and experience could confirm if this is correct...I decided to RTFM (Read The Fine Manual) and saw this on page 237:http://cp.literature.agilent.com/litweb/pdf/08560-90158.pdf"EXT MXR PRE UNPRNot available with an 8560E/EC Option 002 and non-functional in instruments with Option 327. Selects either preselected external mixing mode or unpreselected external mixing mode. This softkey sets the external mixer type, but does not select external mixing. Select external mixing with the EXTERNAL MIXER softkey under AUX CTRL.If the preselected external mixer mode is selected, rear-panel output J8 of the analyzer is automatically switched to the 0.5 V/GHz (FAV) mode with an output of 1.5 V/GHz of the LO frequency. The 1.5 V/GHz of the LO frequency definition is required for the Agilent 11974 Series preselected external mixers. Front-panel key access: CONFIGNOTEThere are two different types of external mixers available, preselected and unpreselected. The EXT MXR PRE UNPR softkey function applies only to the selection of the type of external mixer to be used. It does not switch the analyzer from internal to external mixing.EXTERNALSets the trigger to external mode. Connect an external trigger source to J5 EXT/GATE TRIG INPUT on the rear panel of the spectrum analyzer. The source must range from 0 V to 5 V dc (TTL). The trigger occurs on the rising or falling edge of the signal (about 1.5 V) as selected by the TRIG POL POS NEG softkey function.EXTERNAL MIXERNot available with Option 002 and non-functional in instruments with Option 327. Accesses a menu of functions that allow you to extend the spectrum analyzer frequency range using external mixers. These functions include band and harmonic selection, amplitude correction, signal identification (if available), and setting the external mixer bias.Front-panel key access: AUX CTRLNOTENo external mixing capabilities are available with an 8560E/EC Option 002.Resolution bandwidths less than 300 Hz are not available with external mixers."This would indicate that Option 002 (the built-in Tracking Generator) precludes the use of external mixers, correct?If this is the correct interpretation, it would seem that the choice is either a built-in Tracking Gen with no good ability to get to higher frequencies, or forgo the built-in TG and have the ability to get to higher frequencies with an external mixer. Or maybe there is a work around?Any advice on whether I've got this correct or incorrect would be appreciated. Thanks!

author: Electro Fan
author_rank: Super Contributor
timestamp: February 22, 2015, 11:16:23 pm
content: A few attachments to help clarify the question/problem:When the IF input on the 8560 is removed to make room for the Tracking Generator RF output - how could an external mixer's IF output be connected to an IF input somewhere on the 8560? Or is this a "No Op"? Thx(Why would HP/Agilent have put a zillion I/O connectors on the back of the 8560 and not provided for an IF input for customers who use a built-in Tracking Generator? I'm sure I'm missing something, probably a lot.)

author: alex.forencich
author_rank: Frequent Contributor
timestamp: February 23, 2015, 12:45:48 am
content: The cable for the IF input goes to a port on the 3rd converter. The 3rd converter has an internal switch. I'm not sure what connector is required offhand; it's probably either a right-angle SMA or SMB. This connector should still be available internally; you may just need to route it out somewhere; perhaps to an empty knockout on the back panel.