Tektronix 494AP service manual A o a a a o a o o a O o o o, Narrow Videofilter PEAK/AVERAGE

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Performance procedure_ 4g4Ll4g4ApServlceVol.1 Check

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(4) Check that amplitude deviation from the

100MHzreference_does

checkthatflatn€ssis not,*.""J-*i.sdB. Atso within*1.5 dB.

andc. Connectthe CAL.OUTsignatto the RF tNpUT, performthe <Btue-SHIFT>CAf-iouiin".

15.,Chec_Displayk DVnamicRange and Accuracy (99 jB._il _10dB/DtV moOe,-wirrin-accuracy or :!1.0 dB/l0 dB to^-amaximumcumulativeerrorof *2.0 dB overthe g0 dB window;rO Oe-in2 dBlDtV rnodewfth an accuracyof *0.4 ABpia to a max_ imumcumulativeenor of *1.0 Oe'oveithe 16 dB window;Lin modeis 15% ot fuffica[l-'

a. Connectthe test equipmentas shownin Figure

4-13-using,the lOdB and 1'dBsiep"ti"nrutorr. S"t the SpectrumAnalyzercontrolsas foilows:

Signaf Source

*30 dBm to -80dBm

100 kHz to 10 GHz

CENTER FREQUENCY	100MHz
sPAN/DtV	20 kHz
AUTORESOLN	On
REFLEVEL	*10 dBm
MIN RF ATTENdB	0
VERTICALDTSPLAY	10 dB/DtV
NARROW	On
VIDEOFILTER
PEAK/AVERAGE	FullyClockwise
TrME/DtV
	AUTO

b.Set the attenuatorsfor OdB attenuation.Setthe generatorcontrolsfor a.100MHz outputfrequency,and carefullyset the outputlevelsuchttraitne signatpeakis at the top graticuletine.

c.Add 80 dB of externalattenuationin 10 dB steps and notethat th€ signalst€psdown in 10 dB steps.

SpecfrumAnalyzer UnderTed

Calibraled Altenuators 1 0 d B & 2 0 d 8

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Calfbrated 1OdB and 1 dB step ailenuators or separate 10 dB and i dB attenualors.

Figure 4-13'Test eguipment s€tup for checking dynamic range and accuracy, and preserecror image fejection.

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