Scan Width Accuracy

TM 11-6625-2781-14&P-2

Section IV

PERFORMANCE TESTS (cont'd)

4-23. Input Impedance (cont'd)

4. Set oscillator for 500 kHz and an output level of 15 mV indicated on the voltmeter. -

5. Replace 50-ohm Termination with a cable assembly and connect to analyzer RF INPUT.

6. Measure voltage across analyzer input. For a VSWR of less than 1.3 the voltmeter should indicate should indicate

between 11.8 and 19.0 mV.

11.8

19.0 mV

7. Change oscillator frequency in steps from 500 kHz to 2 kHz. Repeat steps 3 through 6 at each frequency step.

8. Repeat steps 1 - 7 with INPUT ATTENUATION set to 20 dB, then 10 dB.

4-24. Scan Width Accuracy

SPECIFICATION:

Scan widths 10 MHz/div and 20 kHz/div to 20 Hz/div (8552B) or 200 kHz (8552A); frequency error between two points on

the display is less than +3% of the indicated frequency separation between the two points. Scan widths 1 MHz/div to 50

kHz/div; frequency error between two points on the display is less than +10% of the indicated frequency separation.

DESCRIPTION:

Wide scan widths are checked directly using a comb generator. Narrow scan widths are checked using a comb generator

modulated by an audio oscillator. Comb generator frequency components line up opposite graticule lines, and the

amount of error is measured at the +3 graticule line.

Figure 4-5. Scan Width Accuracy Test: 10 MHz/Div

EQUIPMENT:

Comb Generator ................................ ................................ ................................ ................................ ....... HP 8406A

Audio Oscillator ................................ ................................ ................................ ................................ ........HP 200CD

BNC Cable Assembly................................ ................................ ................................ .............................. HP 10503A

Cable Assembly ................................ ................................ ................................ ................................ ...... HP 11001A

Type N to BNC Adapter ................................ ................................ ................................ .......................... UG-201A/U

4-8