Audio Scrambler and Sub-Audio Signalling Processor
CMX138A
10
0
25kHz ch Template (TIA/EIA)
12.5kHz ch Template (TIA/EIA)
All Filters Off ($C2=0000)
+1dB/-3dB WRT ref.
3kHz
25kHz & HPF Enabled ($C2=0C00)
-10
-20
-30
-40
-50
-60
-70
-80
-90
-60 dB/decade
(-50 dB)
-100 dB/decade
(-82.5 dB)
20kHz
10.0
100.0
1000.0
10000.0
100000.0
Frequency (Hz)
Figure 6 Rx 25kHz Channel Audio Filter Frequency Response
20
+11.4dB
Template (TIA/EIA)
12.5kHz Enabled ($C2=3000)
12.5kHz & HPF Enabled ($C2=3400)
10
0
-6dB/octave
-10
-20
-30
-40
-50
-60
-70
-80
-90
10.0
100.0
1000.0
10000.0
100000.0
Frequency (Hz)
Figure 7 De-emphasis Curve for TIA/EIA-603 Compliance
© 2010 CML Microsystems Plc
Page 18
D/138A/2
CMLMICRO [ CML MICROCIRCUITS ]
