Design of analog equalizers for partial response detection in magnetic recording

Analog equalizers offer several advantages, such as high speed, small size, low power, and minimum delay, over sampled digital equalizers. (In this paper, the phrase analog equalizer refers to continuous-time equalizers having poles and zeros.) However, because of their feedback nature, their design often involves extensive search procedures. Recently, an analytical design technique based on equation-error formulation was proposed. In this paper, we study this approach for partial response (PR) equalization and show that it is quite sensitive to the choice of timing phase and it could result in quite suboptimal solution. We improve on it by using an iterative approach similar to that of Steiglitz and McBride. We also present a thorough simulation study to assess the performance loss incurred by low-order analog equalizers and produce performance charts that can be used for selecting the PR target for different channel characteristics. Application of this approach to multi-level decision feedback equalization detection is also discussed