HFA3726
Typical Performance Curves, Modulator (Figure 23 Test Diagram) (Continued)
1dB/DIV.
+10%
0dB
-3dB
1MHz
2MHz
10MHz
FIGURE 18. TYPICAL MODULATOR I/Q 3dB CUTOFF
FREQUENCY CURVE
2%/DIV.
+10%
-10%
-15
-10
-5
0
+5
+10 +15
((900-RTUNE)/RTUNE) * 100%
FIGURE 19.
LPF
TA =
CUTOFF
25oC
FREQUENCY
vs
RTUNE,
VCC
=
3V,
-24dBm
0%
-10%
-60 -40 -20 0 20 40 60 80 100
TEMPERATURE
FIGURE 20. LPF CUTOFF FREQUENCY vs TEMPERATURE
AND VCC (NOTE 14 ON AC ELECTRICAL SPECS,
MODULATOR PERFORMANCE TABLE)
SPAN 50MHz
BW = 100kHz
VBW = 30kHz
VIDEO AVERAGE
280MHz
FIGURE 21. TYPICAL MODULATOR SPREAD SPECTRUM
OUTPUT 11M CHIPS/s, QPSK. RTUNE = 900Ω
12