Wavetek 3000 Instruction Manual page 46

PERFORMANCE TESTS
METHOD
Total Level +13 to
-7
dBm :
±1 .25
dB
(Typ ±0 .75 dB)
Accuracy
-7
to
-77 dBm : ±1 .95
dB
(Typ
±1 .25
dB)
<-77 dBm
±2 .75
dB (Typ
±1 .5
dB)
Accuracy Breakdown
Flatness
(+13 to
-7
dBm) ±0 .75 dB (Typ ±0 .5 dB)
Output Meter
±0 .5
dB
Step Attenuator
±0 .5
dB to
70
dB
(±0 .2
dB calibration error)
±1 .0 dB to 130 dB (±0 .5
dB calibration error)
The
±1 .25
dB level accuracy between +13 and
-7
dBm consists
of the sum of the output meter error
(±O .5
dB) and the flat-
ness
(±0 .75
dB) . Both errors are measured with a power
meter .
The output meter error is measured at
50 MHz in two 10 dB
output ranges (+13 to +3 dBm and +3 to -7 dBm) .
The flatness is measured relative to
50
MHz in 10 MHz steps
between 10 and
520
MHz at
+12,
+3 and -7 dBm output levels .
The level accuracy below -7 dBm depends upon the
output
step attenuator error in addition to the output meter error
and the flatness .
The output step attenuator is a combination of pi-pad sec-
tions of
10, 20,
30, 30 and 40 dB .
These five pi-pads are
programmed by cams to provide 0 to 130 dB of attenuation in
10 dB steps as shown in the table below .
OUTPUT STEP
ATTENUATOR POSITION
ACTIVE STEP ATTENUATOR PADS (X)
dBm 10 dB 20 dB 30 dB 30 dB 40 dB
+ 10
0
- 10 x
- 20
x
- 30 x
- 40 x x
- 50
x x
- 60
x x
-
70 x
x x
- 80 x x
x
- 90
x x
x
-100 x
x x
-
x x x
x
- III
x x x x
-130
x
I
x
'
x
x
x
i