HP 8559A +24, 4-26. DISPLAY FIDELITY (Cont'd)

MODEL 8559A PERFORMANCETESTS

PERFORMANCE TESTS

4-26.DISPLAY FIDELITY (Cont'd)

Algebraically subtract each converted reading (Theoretical Reading Subtracted from Corrected DVM Reading) from previous converted reading. Record results in Table 4-16 (see sample computations). Maximum difference between adjacent readings should not exceed +10 mV, corresponding to f1 dB/10 dB or +0.1 dB/dB. Divide maximum value by 100 to calculate Log Incremental Error (in dB/dB).

dB/dB Log Incremental Error

Replace 10-dB step attenuator with 1-dB step attenuator. Set step attenuator to 0 dB.

Set spectrum analyzer Amplitude Scale to LIN and adjust TUNING control for maximum reading on DVM.

Adjust signal generator OUTPUT LEVEL for DVM reading of 800 mV + offset (step 2) +0.5 mV. Trace should be approximately at top CRT graticule line.

Record DVM reading for step attenuator settings of 6 dB and 12 dB in Table 4-17.

Calculate each Corrected DVM Reading by algebraically subtracting offset recorded in step 2. Record results in Table 4-17.

Algebraically subtract corresponding Theoretical Reading from each Corrected DVM Reading, recording results in Table 4-17. Maximum value should not exceed +24 mV, corresponding to +3% of 800 mV Reference Level. Divide maximum value by 8 to calculate Percent Linear Error.

					% of Reference Level Linear Error
	TABLE 4-17.	AMPLITUDELINEARDISPLAY ACCURACY
Attenuator	D V M		Theoretical			Theoretical
		D V M			Reading Subtracted
Setting	Reading		Reading		From Corrected
		Reading*
(dB)	(mV)			(mV)	D V M Reading
		(mV)
						(mV)
0		+800 (Ref.)	+800		0
6			+401

12+201

I *DVM Reading minus offset recorded in step 2.