Filter
Top Products
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:
[CENTER FREQUENCY)......................................
.20
MHZ
FREQUENCY
SPAN]
.........................................
.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
-10
-10
-20
-20 -30
-30 -40
-40
-50
-50 -60
-60 -70
-70
-80
-80
-90
<*l.O
dB
~f1.5
dB
2-42 Performance Tests