CMX868 View Datasheet(PDF) - CML Microcircuits
Part Name
Description
MFG CO.
'CMX868' PDF : 48 Pages View PDF
Low Power V.22 bis Modem
CMX868
Transmit Output Level
Modem and Single Tone modes
DTMF mode, Low Group tones
DTMF twist (level of high group tones wrt low
group) setting accuracy
Tx output buffer gain control accuracy
Notes
7
7
Min.
-4.0
-2.0
7
-1.0
7 -0.25
Typ.
-3.0
-1.0
-
–
Max.
-2.0
0.0
+1.0
+0.25
Units
dBm
dBm
dB
dB
Notes:
5. % carrier frequency accuracy is the same as XTAL/CLOCK % frequency accuracy.
6 Tx signal % baud or bit rate accuracy is the same as XTAL/CLOCK % frequency
accuracy.
7. Measured between TXA and TXAN pins with Tx Level Control gain set to 0dB, 1k2Ω load
between TXA and TXAN, at VDD = 3.0V (levels are proportional to VDD - see section
1.4.2). Level measurements for all modem modes are performed with random
transmitted data and without any guard tone. 0dBm = 775mVrms.
0
-10
Bell 202
-20
-30
dBm
-40
-50
-60
Notes:
-70
10
100
1000
10000
100000
Hz
Figure 14 Maximum Out of Band Tx Line Energy Limits (see note 8)
8. Measured on the 2 or 4-wire line using the line interface circuits described in section
1.4.2 with the Tx line signal level set to -10dBm for QAM, DPSK, FSK or single tones, -
6dBm and -8dBm for DTMF tones. Excludes any distortion due to external components
such as the line coupling transformer.
© 2004 CML Microsystems Plc
42
D/868/9
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