Tool/software:
When measuring the frequency response with Audio Presicon, CH1 and CH3 showed a drop of about 0.1 dBV in the low frequency range.
(The FR of CH2 and CH4 is flat.)
<Question>
Do you know the reason why CH1 and CH3 showed a drop of about 0.1 dBV in the low frequency range?
Please advise on what to check in order to make it flat.
<What I checked>
• Replaced the AP measurement cable.
• Replaced the 4-ohm resistor.
• Replaced the cable between the EVM board and the 4-ohm resistor.
<Test Conditions>
• The PPC3 and register settings are set to default.
• PVDD = 14.0V
• A 4-ohm resistor is connected to the OUT terminal.
• Audio data is input to the EVM board from the AP via optical connection.
• Normal output is confirmed from CH1 to CH4.
