Digital PMR Radio Processor
CMX7131/CMX7141
6.14 Tx Spectrum Plots
The following figure shows the Tx spectrum when using a suitable signal generator as measured on a
spectrum analyser using the CMX7131/CMX7141 internal PRBS generator. Note that the I/Q mode is
sensitive to variations in dc offset in the modulation path and these must be minimised.
Marker
1
[T1]
-75.85 dBm
RBW
VBW
SWT
500 Hz
kHz
700 ms
RF Att
10 dB
dBm
-75.85 dBm
Marker
1
[T1]
-76.30 dBm
RBW
VBW
SWT
500 Hz
kHz
700 ms
RF Att
10 dB
dBm
-76.30 dBm
Ref Lvl
-18 dBm
2
Ref Lvl
-18 dBm
2
446.09631250 MHz
Unit
446.09631250 MHz
Unit
-18
-18
1
[T1]
1
[T1]
A
A
446.09631250 MHz
-21.19 dBm
-66.25 dB
446.09631250 MHz
-22.02 dBm
-63.35 dB
CH PWR
ACP Up
CH PWR
ACP Up
-30
-40
-50
-60
-70
-80
-90
-100
-30
-40
-50
-60
-70
-80
-90
-100
ACP Low
ALT1 Up
ALT1 Low
-67.42 dB
-83.63 dB
-84.58 dB
ACP Low
ALT1 Up
ALT1 Low
-67.65 dB
-74.93 dB
-74.22 dB
1VIEW
1SA
1VIEW
1RM
1
1
cu2
cu2
cu2
cu2
cu1
cu1
cu1
cu1
C0
C0
C0
C0
cl1
cl1
cl1
cl1
-110
-118
-110
-118
cl2
cl2
cl2
cl2
Center 446.1 MHz
3.5 kHz/
Span 35 kHz
Center 446.1 MHz
Date:
3.5 kHz/
Span 35 kHz
Date:
13:45:44
13:30:09
Two-point modulation spectrum
I/Q modulation spectrum
Figure 27 Tx Modulation Spectra - 4800bps
2014 CML Microsystems Plc
Page 60
D/7141_FI-3.x/6
CMLMICRO [ CML MICROCIRCUITS ]
