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Design >> Analog Design >> how to understand noise in class-D amplifier.
https://designers-guide.org/forum/YaBB.pl?num=1528722889

Message started by Jacki on Jun 11^th, 2018, 6:14am

Title: how to understand noise in class-D amplifier.
Post by Jacki on Jun 11^th, 2018, 6:14am

Hi,
Normally in Class-D amplifier, we focus on power supply noise, THD, power efficiency, and the SNR is usually quite good, and depends on the amplitude of the output signal.
I wonder how to analyze the internal noise of the class-D amplifier if we don't consider the power supply noise?
1. First I think we need to consider the load, normally it is a resistor in series with an inductor in the audio amplifier, I think we can use the KTL to calculate the noise from the load.
2. But how to analyze the noise from the class-D amplifier? Can we use the concept of jitter to look at this part? Because the jitter will change the duty cycle of the PWM waveform at the output of the class-D amplifier, and it will change the SNR.
3. Or how do we convert the internal noise of the class-D amplifier into a noise factor of the KTL?

Jacki