Tektronix 494AP service manual O o a o o A o, O o a a a, A o o o o o a

PerformanceCheckprocedure- 4g4A/494ApServiceVol. 1

^	b:	Check frequency response from	10 kHz to
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10 MHz(lowerendof Band1).

(1) Reconnectthe_testeguipmentas shownin Fig- ure4.12. ResetCENTERFREQUENCYIo 10MHz.

(2) Set the generator output for _20 dBm at 10 MHz,and set the SpectrumAnalyzercontrolsas follows:

CENTERFREQUENCY 10 MHz

SPAN/DIV	500kHz
RESOLUTION	1 MHz
REFLEVEL	-20 dBm
VERTCALDTSPLAY	2 dBlDlV
MIN RF AfiEN dB	O
TIME/DIV	AUTO
PEAK/AVERAGE	FullyCounterclockwise

(3)Manuallytune the Signal Generatortowards 10kHz while simultaneoustytuning the CENTER FREQUENCYcontrol to hold the signal at center screen. Note amplitudedeviation,and the highest and lowestpeaks.

SlOllAL SOTRC€ (10 kltr -.t0 lrtltr)

As the Signal Generatoris tuned towards 10 kHz, the RESOLUTTONon the Spectrum Analyzer must be reset to 100kHz when the generator output frequency reaches

2MHa Also,at approximatety200kHz,the SpectrumAnalyzer SPAN/DIVand RESO- LUTION BANDWIDTHmust be reset to

50kHz and 10 kHz respectivelyto prevent

the 0 Hz spur from interferingwith the sig- nal.

Continue resetting the SpAN/DlV and RESOLUTIONas the generatorfrequencyis luneddowntowards10 kHz.

SPECTRT'TAIIALYZERUIIDERTEST

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Figure4-12.Testequipmentsetupfor measuring10 kHz to 10 MHzfrequencyresponse,

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