CAUTIONS
1.
ThesignalvoltageappliedtoINPUTshouldbelower
than17Vrms.
2.
Toavoidleakageofsignalandminimizetheeffectof
phasedeviation,besuretouseshieldedcablesonthe
inputandoutputoftheunit.Thesecablesshouldbeas
shortaspossible.Thisisparticularlyimportantwhen
pulsesignalsareusedasa signalsource.
3.Whentheunitisusedwiththecasegroundfloatedfrom
thecircuitground,thepotentialdifference(DC+ AC
peak)betweenthesetwopointsshouldnotexceed
±600V.
4.
Dialsetting
Selectappropriatedialsforthedesiredattenuationat
anyfrequency.Notethatthemarkingsoneachdial
indicateapproximatesettingsofattenuationincluding
error.A typicalexampleofattenuationerrorandfre-
quencycharacteristicerrorisshowninTable1,where
100kHzsignalisattenuatedto100dB,e istheerror
3
at1 kHzofeachdialand£fistheerroroffrequency
characteristic.
Theoverallerrordependsonthenumberofdialstobe
usedasexplainedbelow.
I)Whenthedialsaresetto30dBx2=60dB,10dBx 3
=30dB,1 dBx 9 = 9 dBand0.1dBx 10= 1 dB,
thentheoverallerror(e) causedbyeachdialand
frequencycharacteristicisobtainedfromthefollow-
ingequation:
£=
±V(0.152
+ 0.12)+ (0.12+0.12)+ (0.12+0.052;
+
(0.012
+0.052)=±0.28dB
II)Whenthedialsaresetto30dBx 2 = 60dB,10dBx
4= 40dB,then:
£=
±V(0.152
+ 0.12)+ (0.12+ 0.12)= 0.23dB
Aswillbeunderstoodfromtheaboveequations,the
lessthenumberofdials,thehighertheaccuracy.
Table1.TypicalExampleofAttenuationErrorand
FrequencyCharacteristicError
Error 30dBstep 10dBstep 1dBstep 0.1dBstep
±0.15dB ±0.1dB ±0.1dB ±0.01dB
£f ±0.1dB ±0.1dB ±0.05dB ±0.05dB
7
