12. Amplitude Fidelity Test

Equipment Frequency Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3335A Adapter, Type N (m) to BNC (f) . . . . . . . . . . . . . . . . . . . . . HP 1250-0780

Procedure Log Fidelity

1.Set the frequency synthesizer for an output frequency of 20.000 MHz and an output power level of + 10 dBm. Set the amplitude increment for 10 dB steps.

2.Connect equipment as shown in Figure 2-21.

3.Press ~NSTR PRESET) on the analyzer. Key in analyzer settings as follows:

[ C E N T E R F R E Q U E N C Y ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 MHZ FREQUENCY S P A N ] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 kHz

CREFERENCE LEVEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . + 10 dBm

4.Press MARKER SPEAK SEARCHJ@~K~GTJ~MKR + REF LVL) to

center the signal on the display.

5. Key in the following analyzer settings:

FREQUENCY SPAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O Hz

[&Xi, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Hz

6.Press MARKER A. Step the frequency synthesizer output amplitude from + 10 dBm to -80 dBm in 10 dB steps, noting the MARKER A amplitude (a negative value) at each step and recording it in column 2 of ‘fable 2-16. Allow several sweeps after each step for the video filtered trace to reach its final amplitude (see Figure 2-22).

7.Subtract the value in column 1 from the value in column 2 for each setting to find the fidelity error.

 

 

 

‘Ihble

2-16. Log Amplitude Fidelity

 

 

 

 

 

 

 

 

 

 

 

 

 

Frequency

1

2

 

 

 

Fidelity Error

Cumulative

Cumulative

Synthesizer

Calibrated

MARKER A

Amplitude

(Column 2- Column 1)

Error

Error

Amplitude

Amplitude

 

(dB)

 

WV

0 to 80 dB

0 to 90 dB

(mm)

Step

 

 

 

 

 

 

 

(9

(dW

+lO

0 (ref)

 

0 (ref)

 

0 (ref)

 

 

0

- 1 0

 

 

 

 

 

 

 

 

 

- 1 0

-20

 

 

 

 

 

 

 

 

 

-20

-30

 

 

 

 

 

 

 

 

 

-30

-40

 

 

 

 

 

 

 

 

 

-40

-50

 

 

 

 

 

 

 

 

 

-50

-60

 

 

 

 

 

 

 

 

 

-60

-70

 

 

 

 

 

 

 

 

 

-70

-80

 

 

 

 

 

 

 

<*l.O dB

 

-80

-90

 

 

 

 

 

 

 

~f1.5 dB

 

 

 

 

 

 

 

 

 

 

 

2 - 42 Performance Tests

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HP 8568B manual +lO ~f1.5 dB