Tektronix 494AP service manual A o o o o a a o o o a o o o o, Generalterms, Vtdeoimarker

o o a a

O

o

Appendix A - 4g4Al494Ap Service, Vol. 1

GLOSSARY

a

I

o

t

o

O

o o

Io

a

t

o o a o o o o a a o o o a o o o o

O

o

t

I

o o o

gtossary is presentedas an aid

.._-Il"^^1"_l':,*ingto understandthe termsas they aie usedin thi" do"urn"nt and with reference

to spectrumanatyzers.

GENERALTERMS

Center Frequency. That frequencywhichcorresponds to the centerof a frequencyspan,expresseOin hertz.

Baselinecftpper (rntensrfier).

theA meansof increasing tionbrightnessof the signatretativ"i;l;; basetinepor_

of the display.

dBc. Decibelsreferenced

to carrierlevel.

1_8i.. .A unit_to express power level in decibelsrefer- encedto 1 milliwatt.

dBmV. A unit to express voltage levels in decibels referencedto 1 millivolt

dBpV. A unit to express voltage levels in decibets referencedto 1 microvolt.

Efrectlve.Frequency_.T:1g.".
				That range of frequency
over which the instrument performanie is specified.
The lowerand upperlimitsare						n".tr.
EnvelopeDisplay.				"if.""r"t:in
		The displayproduced
anatyzerwhen the resotutibn					on a spectrum
						greatertnan
the spacingof the individual bino*iOt ii
				trequenci
FreguencyBand. A			part		"o,ipon"nt".
				of effectjve
					frequency
overwhichthe freouency							range
			can be adlusted,
hertz.						Lxpressedin
Full .Span	(MaximumSpan). A rnode of operation in
whichthe spectrumanatyzer							tr"qu"n"y
band.				"""n,	"n "ntir"
lnterm-odulation
Distortion	-	Spurious Response(lntermodulation
		tMD). An..unwanre; ;d;i;*					anatyzer
responseresultingfrom the mixing					of the nth order fre_
quencies,
due to non-linear							spectrum
				elemintsot in"
analyzer, the resultant unwanted ,".fonr" being
displayed.
Llne Display. The display produced on a							spectrum
anatyzerwhenthe resolution'bandwidih							thanthe
spacingof	the signarampritudes				i"	t"."
				of the individuar
qu€ncycomponents.							fre-
Llne SpectruT.A spectrumcomposed
tudesof the discrete					of signalampli-
		frequency
				components.

Markers.The instrumentusesthreetyp€s of markers:

WaveformMarkers. _ Whenthe Markerfunction is enabled, it provides a movable cursor with readoutof frequencyand amplitudeat the marker position.Whenthe deltamarkermodeis enabled,a second marker allows operations and readout between the two_ marker positions. (Also see WaveformMarkerTerms.)

UpdateMarker. - Marksthe currentsweepposi_ tion in a digitat storage disptayas the disptiy is beingupdated.

Video Mark

VTDEOIMARKER

9{"_rrylinpul from a Tektronix 1405 TelevisionSidebandAnalyzer. The Video Markersmark frequenciesof intereston the televi- sionsignal.

MaximumSafeInputpower

WITHOUTDAMAGE...Themaximumpower apptied at the inputwhichwill not causedegiadationoi the instrumentcharacteristics.

WITHDAMAGE.The minimumpowerappliedat the

'

inputwhichwill damagethe instrument.

PulseSfetcher. A pulse shaperthat producesan out_ put pulse, whose durationis greaterthan that of the inputpulse,and whoseamplitudeis proportionalto that of thepeakamplitudeof the inputpui"e.'

ScanningVelocity. Frequencyspan dividedby sweep timeandexpressedin hertzpir second.

Signal ldentitier. A meansto identifythe spectrurno, theinputsignalwhenspurious,esponsesarepossible.

Video. The term is usedheregenerallyto meana sig_ nal afterthe detectorstage. lt can also be usedmore specificallyto meana baseband(zerocarrierfrequency) televisionsignal.

VideoFilter.A post detectionlow_passfilter.

Zero Span.A modeof operationin whichthe frequency spanis reducedto zero.

o

A-1

I