Nokia 300 Service Manual page 72

RM-781
BB Troubleshooting and Manual Tuning Guide
Measurement data
If a special low-pass filter designed for measuring digital amplifiers is unavailable, the measurement must be performed with a
current probe and the input signal frequency must be 2kHz.
Figure 7 Differential output waveform of the Ext_in_IHF_out out loop measurement when speaker is connected.
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