Marine VHF Audio and Signalling Processor
CMX885
AC Parameters (continued)
Analogue Channel Audio Filtering
Pass-band (nominal bandwidth):
Received Audio
Notes
Min.
Typ.
Max.
Unit
91
92
93
300
300
300
–
−2.0
33.0
–
–
–
–
0
0
–
−47
−74
3300
2550
3000
–
+0.5
–
Hz
Hz
Hz
dB
dB
dB
dBm
dBm
12.5kHz Channel Transmitted Audio
25kHz Channel Transmitted Audio
Pass-band Gain (at 1.0kHz)
Pass-band Ripple (wrt gain at 1.0kHz)
Stop-band Attenuation
Residual Hum and Noise Tx
Residual Hum and Noise Rx
96
96
–
–
–
Pre-emphasis
De-emphasis
94
95
–
–
+6
−6
–
–
dB/oct
dB/oct
Audio Scrambler
Inversion Frequency
Passband
–
300
3300
–
–
Hz
Hz
3000
91
The receiver audio filter complies with the characteristic shown in Figure 6.
Notes:
The high pass filtering removes sub-audio components from the audio signal.
The 12.5kHz channel filter complies with the characteristic shown in Figure 9.
The 25kHz channel filter complies with the characteristic shown in Figure 8.
The pre-emphasis filter complies with the characteristic shown in Figure 10.
The de-emphasis filter complies with the characteristic shown in Figure 7.
Psophometrically weighted. Pre/de-emphasis and 25kHz channel filter selected.
92
93
94
95
96
© 2010 CML Microsystems Plc
66
D/885/3
CMLMICRO [ CML MICROCIRCUITS ]
