Nokia RM-237 Service Manual page 135

RM-237
BB Troubleshooting and Manual Tuning Guide
The gain values presented in the table apply for a differential output vs. single-ended/differential input.
Loop test
External Mic to
External Earpiece
External Mic to
Internal Earpiece
External Mic to
Internal handsfree
Internal Mic to
External Earpiece
Measurement data
Figure 37 Single-ended output waveform of the Ext_in_HP_out measurement when earpiece is connected.
Issue 1
Input Output
terminal terminal
XMICP and HSEAR R
GND and GND
HSEAR L and
GND
XMICP and EarP and
GND GND
EarN and
GND
XMICP and E2101 pad
GND
E2102 pad
B2100 (OUT/ HSEAR R
GND) and GND
HSEAR L and
GND
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Path Input
gain voltage
[dB] [mVp-p]
(fixed) voltage
-2.9 1000
-4.0 750
8.5 920
22.7 100
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Differe Outp Output
ntial ut DC current
output level [mA]
[V]
[mVp-
p]
720 1.2 NA
490 1.2 NA
2520 0 25mA
(calc.)
1360 1.2 NA
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