Tektronix 494AP service manual A a a, Peavaverage

POWERMETER

SPECTRUMANALYZERUNDERTEST

SIGNALSOURCE

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ADAPTEFADAPTER

POWEBDIVIDEB

POWERSENSORADAPTEF

LOWLOSSCOAXCABLEWITHSMACONNECTORS

Figure 4.14. RF attenuator test equipment setup,

Change step 14 as follows:

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14. Check Frequency Response

(Responseaboutthe midpointbetweenlwo exlremes measuredwith 10 dB of RF attenuationand peaking optimizedin the applicablebands for each cenrer lreguencysetting is as lollows:

Band1: +1. 5 dB from 10 kHz to 1 . 8GHz

Band2'r2. .5 dB from 1.71o5.5 GHz

Band3: f2.5 dB from 3 to 7.i GHz

Band4: +3.5 dB from 5.4 to 18 GHz

Band5: +5.0 dB from 15 to 21 GHz)

(Responsewith respectto 1OOMHz is as follows: Band 1: .t2.5 dB from I O kHz to 1.8 GHz

Band2: +3.5 dB from 1.7to 5.5 GHz Band3:13.5 dB from 3 to 7.1 GHz

Band4:14.5 dB from 5.4 to 18 GHz Band 5: +6.5 dB from 't5

to 21 GHz)

Thefolfowingproceduretestdisplayflatness(peakedat center of test frequency range, typically 1 dB greaterthan Trequencyresponse,see specificationTable 2-2)

lf any rangesegmentfailsto meetthe specification,set the FREOUENCY to the center of the range in question, apply a markerat the centerfrequencyof the range,andre- peak with the MANUALor AUTO PEAKING.Decreaselhe FREOUENCYSPAN/DlVto displaythat rangeand recheck the response.

The responseat eachcheckpointaboveband 1, should be peaked with the MANUALPEAK control.

a. Checklrequencyresponsefrom0.01GHzto 21GHz (Band 1 through5)

{1) Conneclthe CALOUTsignalto the RF INPUT,and performthe <Blue-SHIFT>CAL routine.

(2) Set the SpectrumAnalyzercontrolsas lollows:

CENTERFREOUENCY 100MHz

SPAN/DIV	500 kHz
RESOLUTION	3 MHz
REFLEVEL	-20d9m
VERTICALDISPLAY	2 dB/DIV
MIN RF ATTENdB	10
TIME/DIV	AUTO
PEA}VAVERAGE	Fully Counterclockwise

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