Abstract: A system and method for calibrating a multi-bit feedback quantizer in a delta-sigma modulation system. A digital data pattern corresponding to a particular DAC code of a multi-bit digital-to-analog converter is transmitted in the transmit channel, where the DAC code is proportional to an analog voltage signal. An effective DC component of the digital data pattern is realized and converted to corresponding digital DC component values. A predetermined number of samples of the digital DC component values are averaged to provide an average sample value. A digital code in the multi-bit feedback quantizer is replaced with the average sample value.

Abstract: A method is provided for elimination of periodic inter symbol interference (ISI) resulting in timing phase steps and channel amplitude control steps occurring following a periodic preamble pattern, such as a 1/4 T sine wave pattern and at the beginning of a random pattern user data field in a partial response, maximum likelihood digital magnetic data storage channel. The method comprises the steps of: determining a periodicity of periodic ISI events in relation to main magnetic flux transitions during playback of a periodic signal waveform thereof, writing a new preamble field to the magnetic data storage channel of a periodic signal waveform preceding the user data field in which the phase of the periodic signal waveform is shifted, e.g.