Tektronix 494AP service manual +tAF. x BEF + 20 + 4NHz, Freouencyrelatedcharacteristics

Characteristic

SignalCounter(continued) DeltaFrequencyAccuracy

Sensitivity

ReadoutResolution

ReferenceFrequencyError

AgingRate

ShortTerm

Specification- 494Al4g4ApService,Vol. 1

-Tabte2-1(Continued)

FREOUENCYRELATEDCHARACTERISTICS

		tal Inlormation
+tAF. x BEF)+	(20 + 4N)Hz	Refer to lF Frequency,
	+
1LSD]		LO Range,
		and HarmonicNumber specification
Where		laterin thistablefor the N vatue

AF: DeltaFrequency

REF Reference Frequency Error

N : HarmonicNumber !9D - LeastSignificantDigit

Signallevel,at center screenor at marker, must be 2A dB or rnore above the averagenoise level and within60 dB of the referencelevel.

Selectablefrom Hz to 1 GHz with <blue-SHIFT>COUNT RESOLU- TIONpushbutton.

(1x19 - s perday

(7x10-e perweek

Firstsix months

After the first six months

Accuracy during warmup at +25oC(30qlin.afterpoweron)

Temperaturesensitivity

ResidualFM

Bands1 & 5-12 with SpAN/DV ((7 kHz)Ntotalexcursionin 20 ms

>200 kHz, and Bands2-4 with SPAN/DIV>100 kHz

(1x10 - 7 in first six months

(1x.t0-z peryear

within 5x10-8 of the frequencyafter 24 hours

Within 2x10-8 over the instrument operatingrange ol -1SoCto +55"C (referencedto +25"C)

Shortterrn,after t hourwarmup

Refer to lF Frequency,LO Range, and HarmonicNumberspecification laterin thistablefor the N value

Bands 1 & 5 - 12 with SpAN/DIV (200 kHz, and bands 2-4 with SPANIDV(100 kHz

1st LO lock

Static Resolution Bandwidth (6 dB down)

ShapeFactor

60 dB bandwidth

{(10+2N)Hz total excursionin 20 rns

Within 20/" ot selectedbandwidth

( 1 5 0 H z

Refer to lF Frequency, LO Range, and Harmonic Number specification later in this table for the N value

10 Hz to 1 MHz in decadesteps,and M H z

Within 20"h, impacted by residual FM and drift during sweep time

3 MHz-100Hz

Noise Sidebands

7.5:1or less

At least -70dBc at an offset of 30 x the selectedbandwidthfor resolution bandwidthsof 100 Hz and 1OHz

At least -75dBc at an offset of 30 x the selected bandwidth for all other bandwidths

2-3