Method for Evaluating Partial Response Maximum Likelihood System Performance Using Sequenced Amplitude Margin

We improve a media evaluation method for partial response maximum likelihood (PRML) systems using a sequenced amplitude margin (SAM). The improved method has many advantages over direct bit error rate (BER) measurement; it needs fewer samples and less time, it does not require a known test pattern, and it enables easy measurement of media characteristics without the influence of media defects. Some experimental results indicated that the calculated BERs correspond to the directly measured BERs in any type of optical disk system.