Model3490APERFOBMANGECHECKS

Section V

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Figure5-4. AC Normal-ModeReiectionTest.

f.Connect jumper across I MQ resistor and note 3490A reading.

g.Remove jumper. 3490A reading should change between 000.908V and 000.910V. This verifies an input resistanceof 10 MQ x O-15%.

5-28AC.VOLTMETEHINPUTIMPEDANCETEST.

5-29. A test oscillator (-hp 652A) and two precision resistors, I MO t O.l % (-hp- 06984369) and l0 kQ t 0.1 % (-hp-06984157),arc requiredfor this test.

a.Connect 3490A, test oscillator,and I Mfl resistor

(\)as shown in Figure 5-6. Connect jumper across

resistorasindicated.

b.Set 349OAFUNCTION to AC, RANGE to I V.

c.Adjust test oscillator frequencyto 25H2. Adjust output amplitude to obtain a 3490A reading of 1.00000v.

d.Remove jumper from resistor Rs. 3490A display shouldbe not lessthan 0.65975V if the instrument does not have the rear input connector, or not less than 0.65804 if it doeshavea rearinput connectorin parallel with the front input terminals.

e.Replace the l Mfl resistor (R5) with a l0k{-2 resistor.Connectjumper acrossresistor.

f.Adjust test oscillator frequency to 250 kHz. Ad- just output amplitude for 3490A readingof 1.00000V.

g.Removejumper from lOkfl resistor.3490A dis- play should be not less than O.492ll V if the 3490A does not have rear input connector, or not less than 0.41321V if it doeshavethe rearinput.

$30.SAMPLE/HOLDPERFORMANCE (0ption040/045).

--5-31. The dc voltage meursurementperformance of the 3490A must be within specification before proceeding

D C S T A N D A R DD/I F F E R E N T I A L

VOLTMETER

MULTIMETER

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3490A B - 2948

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Figure5-5. DC Voltmeter Input ResistanceTest.

5-5