Tektronix 494AP service manual SETTTNGS2, Rcsct, Tion Bandwidth, Tionbandwtdth

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Adjustnent Procedure-

4g4[l4g4Ap Service Vot. 1

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Figure 5-17. Adiu3tments on the front of the Variabte Resolution module.

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(29) PressRECALL

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SETTTNGS2.

p.

Deactivate SAVE A and then reactivate to save

Adjust C4060.in

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!30)

the 10 Hzl100

the 10 kHz display.

Hz Bandpass

Filterassemblyfor bestsymmetry.

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lgtt Repeat parts 2g

through 31 to etiminate

q. Set FREQ SPAN/DV to 50 kHz and RESOLU_

TION BANDWIDTHto 100 kHz.

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interaction.

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(32) Removeail jumpers from the 10 Hzl100Hz

,

r.

Adjust C3045, C3039, and C3030 (Figure 5_15)

Bandpass

for

100 kHz

response centered about

the

Filterassembly.

the best

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(33) press

<Btue-SHtFT>CAL to startthe internat

10 kHz filter reference.

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calibrationroutine. press

FINEto continu€calibra_

s. Check the waveshape, bandwidth, and centering

tion as prompted.

of all filters. lf necessary, make only fine or minor

t

K. RCSCT

adjustments.

Figure

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5-1

shows typical response

thE RESOLUTIONBANDWIDTHtO1OOHZ

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and FREQ SpAN/Dtv to 50 Hz. set the REF LEVEL

shapes.

su-chthat the responseis near the amplitude

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reference.

of the

t.

Level th€ gain of the filters as follows:

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L Disconnectthe 10

MHz third converter

(1) SCt thE FREQ SPAN/DIVtO 5OOKHZ,RESOLU-

from J683 and

reconnectit

lF signal

to

p6g3

to

TION BANDWIDTH to 1OOKHz, and REF LEVEL to

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J683.

J690. Reconnect

-20 dBm.

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m. set the FREQspAN/DlV

to 1 kHz, RESOLU-

TION BANDWIDTH

(2)

Adjust all filters to the 1OOkHz tevet as p€r

the

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to 1 kHz and reset the REFLEVEL

tor a 7 divisiondisptay.ActivateSAVEA.

follovying Table 5-3.

Change FREQ SPANIDIV as

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n. set

necessary to maintain a

display.

th€ FREQspAN/DtV

"suitable

TIONBANDWTDTH

to 10 kHz, RESOLU-

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to 10 kHzandadjustREFLEVEL

u.

Press

<Blue-SHtFT> PULSE STRETCHER

a 7 divisiondisplay.

for

(DIAGNOSTIC FUNCTTONS) and setect item

#s

t

o. Adjust C2030(Figure5-1S)for the best 1OkHz

(DISABLE/ENABLEUSE OF CAL FACTORS),then item

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responsecenteredaboutthe 1 kHz reference.

#1 (USE RESULTS),to re-enable use of cal factors.

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5-17

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