Baseband Processor For Mixed Mode Land Mobile Radio
CMX880
CTCSS Encoder
Frequency Range
60.0
-1.0
260
0.2
+1.0
4.0
Hz
%
dB
%
Tone Frequency Resolution
Tone Amplitude Tolerance
Total Harmonic Distortion
61
62
2.0
2.0
Selcall Encoder
Frequency Range
300
-1.0
3000
0.2
+1.0
4.0
Hz
%
dB
%
Tone Frequency Resolution
Tone Amplitude Tolerance
Total Harmonic Distortion
65
62
DTMF Encoder
Output signal level
High tone
Low tone (twist on)
(twist off)
0
-2
0
dB
dB
dB
%
66
66
Output distortion
2
5
DCS Encoder
Bit Rate
Amplitude Tolerance
134.4
775
bits/s
dB
61
-1.0
-1.0
+1.0
FFSK/MSK Encoder
Output signal level
Output level variation
Output distortion
mVrms
dB
+1.0
5
3
%
%
3rd harmonic distortion
Logic 1 freq
Logic 0 freq
1200baud and 2400baud
1200baud
2400baud
1198
1798
2398
1200
1800
2400
1202
1802
2402
40
Hz
Hz
Hz
ms
Isochronous distortion (0 to 1 and 1 to 0)
C4FM Encoder
Output signal level
Output DC offset wrt VDD/2
Symbol Rate
63
63
1000
+50
mVrms
mV
S/s
-50
-50
4800
4800
Symbol Rate Drift
64
10
ppm
CQPSK Encoder
Output signal level
Output DC offset wrt VDD/2
Symbol Rate
63
63
1000
+50
mVrms
mV
S/s
Symbol Rate Drift
64
10
ppm
Notes:
61.
62.
63.
VDD(A) = 5.0V and TX Sub-Audio Level set to 88mV p-p (31mV rms).
Measured at MOD_1 or MOD_2 output.
Measured after external RC filter (R10,C12/R11,C13) for a “+3 +3 - 3 - 3 ...” symbol
sequence, with VDD = 5V and the Unit Level set to 2048. The output levels are
proportional to VDD
.
64.
65.
66.
Dependant on crystal or clock accuracy.
VDD(A) = 5.0V and TX Selcall Level set to 881mV p-p (308mV rms).
With respect to High Tone
ã 2001 Consumer Microcircuits Limited
74
D/880/1
CMLMICRO [ CML MICROCIRCUITS ]
