Tektronix 1L40, Инструкция по эксплуатации

Страница: 64 / 145

Performance C heck/Calibration— Type 1L40
Fig. 5-8. Test oscilloscope d ispla y when C 504 and C508 are cor­
rectly adjusted. DISPERSION 50 kH z/C M , RESOLUTION fu lly clock­
wise.
(A ) Adjustm ents on honeycomb assembly.
Fig. 5-9. Location o f the resolution adjustments.
1. A djust R543 fo r a
resolution ba ndw idth
> 100 kHz w ith
RESOLUTION control
fu lly clockwise and
on a p p r o x i m a t e
ba n d w id th o f 60
kHz fo r this display
(one position back
from fu lly c w ).
2. A djust L624 fo r op­
timum signal a m p li­
tude
w ith rounded
shoulders a t this
point.
4. A djust C620 fo r sym­
metry in this region.
3. A djust C610 fo r sym­
metry in this region.
(A ) Correct d isp la y w ith RESOLUTION control a t the 1st
position back from the Full clockwise (1 0 0 kHz) posi­
tion.
Dispersion 50 kH z/cm .
(B) Incorrect displa y L624 misadjusted. Shoulders are too
pronounced.
Fig. 5 -1 0 . Typical displays when adjusting the resolution ba ndw idth
w ith C610, C620, L624 and R543.
I. Adjust the bandpass of the 5 MHz filter as follows:
(1) . ADJUST— the 100 kHz Resol Cal R543 (Fig. 5-9), to
obtain a bandpass between 100 kHz and 120 kHz at the -—6
dB point. (Fig. 5-6A.)
(2) . Switch the RESOLUTION control back one step from
the fully clockwise position.
(3) . ADJUST— C610, C620 and L624 (Fig. 5-9) for a re­
sponse on the indicator oscilloscope similar to Fig. 5-1OA.
Adjust C610 for optimum symmetry at the base of the band­
pass response and adjust C620-L624 for response slope and
symmetry at the upper portion of the display.
NOTE
Install the Type 1 L40 info the com partm ent o f the
a n a ly z e r oscilloscope and a llo w the unit to s ta b i­
lize to the o p e ra tin g tem perature. Check the b a n d ­
pass response. If the response is non-sym m etrical,
remove the oscilloscope side panel and adjust
C 610 a slig h t am ount fo r correct symmetry.
(4) . Switch the RESOLUTION control to the fully clock­
wise position. Adjust the G A IN control for a 6 cm display
5-10