FSK Modem and DTMF Codec
CMX865
Rx Modem Energy Detector
Detect threshold (‘Off’ to ‘On)
Undetect threshold (‘On’ to ‘Off’)
Hysteresis
Notes
8, 9
8, 9
Min.
-
-48.0
2.0
Typ.
Max.
-43.0
-
-
Units
dBm
dBm
dB
-
-
-
8, 9
Detect (‘Off’ to ‘On’) response time
300 and 1200baud
150 and 75baud
8, 9
8, 9
8.0
16.0
-
-
30.0
60.0
ms
ms
Undetect (‘On’ to ‘Off’) response time
300 and 1200baud
150 and 75baud
8, 9
8, 9
10.0
20.0
-
-
40.0
80.0
ms
ms
Rx Answer Tone Detectors
Detect threshold (‘Off’ to ‘On)
Undetect threshold (‘On’ to ‘Off’)
Hysteresis
Detect (‘Off’ to ‘On’) response time
Undetect (‘On’ to ‘Off’) response time
Notes
8, 10
8, 10
8, 10
8, 10
8, 10
Min.
-
-48.0
2.0
30.0
7.0
Typ.
-
-
Max.
-43.0
-
Units
dBm
dBm
dB
ms
ms
-
-
33.0
18.0
45.0
25.0
2100Hz detector
‘Will detect’ frequency
‘Will not detect’ frequency
2050
-
-
-
2160
2000
Hz
Hz
2225Hz detector
‘Will detect’ frequency
‘Will not detect’ frequency
2160
2335
-
-
2285
-
Hz
Hz
Rx Call Progress Energy Detector
Bandwidth (-3dB points) See Figure 6a
Detect threshold (‘Off’ to ‘On)
Undetect threshold (‘On’ to ‘Off’)
Detect (‘Off’ to ‘On’) response time
Undetect (‘On’ to ‘Off’) response time
Notes
Min.
275
-
-42.0
30.0
6.0
Typ.
-
-
Max.
665
-37.0
-
45.0
50.0
Units
Hz
dBm
dBm
ms
8, 11
8, 11
8, 11
8, 11
-
36.0
8.0
ms
Notes:
9. Thresholds and times measured with continuous binary ‘1’. Fixed compromise line
equaliser enabled. Signal switched between off and -33dBm.
10. ‘Typical’ value refers to 2100Hz or 2225Hz signal switched between off and -33dBm.
Times measured wrt. received line signal.
11. ‘Typical’ value refers to 400Hz signal switched between off and -33dBm.
© 2005 CML Microsystems Plc
38
D/865/3
CMLMICRO [ CML MICROCIRCUITS ]
