Tektronix 494AP service manual @o@o@g@@, Ext

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PerformanceCheckprocedure- 4g4Al4g4ApServiceVol. 1

TEST SPECTRUMANALYZER

TO10tlHz tFOUTPUT	STEP ATTEI{UATOR			RF INPUT
(REARPANEL)
				SIGNAL GENERATOR	POWERMETER
			@o@o@g@@
SPECTRUTTI		RF INPUT		OUTPUT
ANALYZER

UNOERTEST

STEP ATTENUATORS

Flgure4'19.Test equrpmentsetuptor checkrng1 dB inputcompressionpoinl

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-20l. Checkthat the 1 dB compressionpointoccursat dBm or less(20dB or less attenuationOetweenthe

generatorandthe RF INPUT).

26.Check External Reference Input power (+15dBmto -15dBm)

(1MHz,2 MHz,5 MHz,or 10 MHz.)

a. Connectthe outputof a signalgenerator

to a fre- quency counter and set the generator frequencyto 10MHz*50 Hz.

b.Disconnect the generator output from the counter,and connectit to the EXTERNALREFERENCE Input connectoron the rear panel of the Spectrum Analyzer.

c.Setthe generatoroutputlevelto *1 5 dBm.

...d..Monitorthe SpectrumAnalyzerCAL OUTsignal withthe frequencycounter.

e.Checkthat the crt readoutfor REF OSC reads

EXT.

f.Checkthatthe frequencycounterreads100MHz.

g.Reset the output of the signal generator to

-15 dBm .

h.Checkthat crt readoutstill readsEXTandthe fre_ quencycounterstillreads10x the referencesourcefre_ quency. lf the crt readout changesto E_U(External Unlock), recheck the external referencesource fre- quencytor 10MHz *S0 Hz at -15dBm.

27.Check Triggering Operation and Sensitivity

.(lnternaltrigger:2 divisionsor more)

{Externaltrigger:1.0V peakfrom.t5 Hz to 1 MHz)

a.Connectthe test equlpmentas shownin Figure

4-20.

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4-31