Low Power V.32 bis Modem
CMX869
DTMF Decoder
Notes
Min.
Typ.
Max.
Unit
Valid input signal levels
(each tone of composite signal)
7
7
-30.0
-
0.0
dBm
Not decode level
(either tone of composite signal)
Twist = High Tone/Low Tone
Frequency Detect Bandwidth
Frequency Not Detect Bandwidth
Max level of low frequency noise (i.e dial tone)
Interfering signal frequency <= 550Hz
Interfering signal frequency <= 450Hz
Interfering signal frequency <= 200Hz
Max. noise level wrt. signal
DTMF detect response time
DTMF de-response time
Status Register b5 high time
‘Will Detect’ DTMF signal duration
‘Will Not Detect’ DTMF signal duration
Pause length detected
-
-
-
-
-
-36.0
6.0
-
dBm
dB
%
-10.0
±1.8
-
±3.5
%
11
11
11
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.0
10.0
20.0
-10.0
40.0
30.0
-
-
-
-
dB
dB
dB
dB
ms
ms
ms
ms
ms
ms
ms
11, 12
14.0
40.0
-
30.0
-
25.0
-
-
Pause length ignored
15.0
Notes:
11. Referenced to DTMF tone of lower amplitude.
12 Flat Gaussian Noise in 300-3400Hz band.
Receive Input Amplifier
Notes
Min.
Typ.
Max.
Units
Input impedance (at 100Hz)
Open loop gain (at 100Hz)
Rx Gain Control Block accuracy
10.0
MΩ
V/V
dB
10000
-0.25
+0.25
© 2004 CML Microsystems Plc
43
D/869/4
CMLMICRO [ CML MICROCIRCUITS ]
