Pulse Modulated Amplifiers of both analog and digital input type, have won great interest during the past few years. The technology is now so advanced that excellent audio performance can be combined with the inherent high effciency of the switching Class-D operation of the output stage. This paper describes advances made within digital input Pulse Modulated Amplifier based on digital pulse modulation. An advanced feedback method is evaluated that does not require A/D conversion - PEDEC (Pulse Edge Delay Error Correction). PEDEC decreases significantly harmonic distortion as well as it contributes to minimising the effects of supply pumping problems. A PEDEC based digital PMA system is benchmarked against the well known non-feedback digital PMA by actual hardware measurements. Lastly a new method, Intelligent Volume Control, is introduced as a solution to overcome the inherent dynamic range imitations and in addition to offer significant e ciency and Electromagnetic Interference (EMI) advantages.
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