CMX624P4 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX624P4' PDF : 26 Pages View PDF
V23 / Bell 202 Modem
CMX624
DTMF Transmitter
Level at TOP pin; tones in High Group
Twist (level of High Group tones WRT level of
Low Group tones)
Tone frequency accuracy (worst case)
Notes
4
Min.
-1.0
-
-0.5
Typ.
0.0
+2.0
-
Max.
+1.0
-
+0.5
Unit
dBm
dB
%
Tx Filter and Output Buffer
Change in level at TOP pin caused by changing
bit 2 of FSK MODE Register
Buffer output signal swing;
Load greater than 500Ω.
Notes
5
Min.
2.5
2.2
Typ.
3.0
-
Max.
3.5
-
Notes:
5. For each of the TXON (if enabled) and TXO pins, load between pin and VDD / 2.
Unit
dB
Vp-p
FSK Demodulator and Rx UART
Valid Input Level Range
Acceptable Twist (Mark level WRT Space level)
Acceptable Signal to Noise Ratio
Rx 1200bits/sec (V.23 mode)
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Rx 75bits/sec (V.23 mode)
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Rx 1200bits/sec (Bell 202 mode)
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Rx 150bits/sec (Bell 202 mode)
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Notes
6
7
8
8
8
8
Min.
-43.0
-7.0
20.0
1188
1280
2068
TBD
TBD
TBD
1188
1180
2168
TBD
TBD
TBD
Typ.
-
-
-
1200
1300
2100
75
390
450
1200
1200
2200
150
387
487
Max.
-9.0
+7.0
-
1212
1320
2132
TBD
TBD
TBD
1212
1220
2232
TBD
TBD
TBD
Unit
dBm
dB
dB
Baud
Hz
Hz
Baud
Hz
Hz
Baud
Hz
Hz
Baud
Hz
Hz
Notes:
6. Measured at point A in Figures 8a and 8b, for VDD = 5.0V. The internal threshold levels
are proportional to VDD. To cater for other supply voltages or different signal level ranges
the voltage gain of the Rx Input Amplifier should be adjusted by selecting the appropriate
external components as described in Section 1.6.1.
7. Flat noise in 300-3400 Hz band for V.23, 200-3400 Hz for Bell 202.
8. Set by Rx UART and Xtal frequency.
2100Hz Detector
‘Will Decode’ Frequency Range
‘Will Not Decode’ Frequency Range
‘Off’ to ‘On’ time
‘On’ to ‘Off’ time
Notes
9
9
Min.
2040
<2010
-
4.0
Typ.
-
-
-
-
Max. Unit
2235
Hz
>2265 Hz
25
ms
-
ms
Notes:
9. 2100Hz detection requires a signal within the amplitude range given in the Rx Energy
Detector section.
2003 CML Microsystems Plc
21
D/624/7
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