PMR Signalling Processor
CMX881
AC Parameters (cont.)
Notes
Min.
Typ.
Max.
Unit
Analogue Channel Audio Filtering
Pass-band (nominal bandwidth):
Received voice
71
72
73
300
300
300
3000
2550
3000
Hz
Hz
Hz
dB
dB
dB
dBp
12.5kHz channel transmitted voice
25kHz channel transmitted voice
Pass-band Gain (at 1.0kHz)
Pass-band Ripple (wrt gain at 1.0kHz)
Stop-band Attenuation
0
-2
+0.5
33.0
Residual Hum and Noise
76
-50
Pre-emphasis
De-emphasis
74
75
6
dB/oct
dB/oct
−6
71
The receiver voice filter complies with the characteristic shown in Figure 5. 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 6.
dBp represents a psophometrically weighted measurement.
Notes:
72
73
74
75
76
2004 CML Microsystems Plc
55
D/881/7
CMLMICRO [ CML MICROCIRCUITS ]
