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ddnp-prml Schedule for this course

2 Day Course

This course is for anyone who needs to come quickly up-to-speed on data storage read channels. It focuses on detection methods and practical considerations for perpendicular recording that lead from the fundamentals of signal detection to Noise Predictive Maximum Likelihood (NPML), or Noise Predictive Viterbi (NPV), and on to Data-Dependent Noise Prediction (DDNP).

You will understand the difference between PR (partial response) and ML (maximum likelihood sequence detection) and how they work together to form the industry standard of data detection. Plus, you will gain an intuitive understanding of correlated noise, its causes, and how it affects NPML/NPV channels. You will also understand key practical considerations such as data dependencies, non-linearities, detector target optimization, recording codes, gain and timing recovery, and filter adaptation, as well as how the system works and its tradeoffs.

Additionally, many attendees from the tape, optical disc, and flash memory industries have found the course material and insights provided useful and applicable to their systems. We also briefly introduce current topics such as turbo codes, LDPC codes, iterative detection, discrete-track recording, low SNR timing recovery, and “software” channels. Some of topics are covered in greater detail in our companion course Introduction to Iterative Detection.

The course is designed for those new to recording channels, while providing industry veterans with a clear, concise review of key topics and the insight and context needed to understand and assess new developments. Suitable industry experience or previous disk drive technology training will satisfy the prerequisites.
 

Perpendicular Recording Process Overview
Read and Write Process
NRZ and NRZI Data Sequences
Response Models
Intersymbol Interference (ISI)
User Density

Read Channel Basics

The Typical Drive Layout
Data Rate
Error Mechanisms
White Gaussian Noise 
Calculating BER Performance

Maximum Likelihood Sequence Detection

The Viterbi Algorithm Revealed!
Path Metric Calculation
Simplifications

Signal Non-Linearities

What is Linearity?
Non-Linear Transition Shift (NLTS)
Media Noise (Transition Jitter)
Partial Erasure 
Asymmetry
Thermal Asperities

Signal Processing Basics

Sampling Bandlimited Signals
Aliasing
Transforms: D, Fourier
Sinc Function
Filtering and Modeling

Traditional Partial Response Targets
Developing Intuition
Class 4 Partial Response
Traditional PR4, EPR4, EEPR4 Targets
'Natural Density'
Class 1 and Class 2
The ‘Ideal’ Target?

Error Events in Sequence Detectors

(Minimum) Euclidean Distance
Calculating BER Performance
What Causes an Error?
Error Event Notation  

Adaptive Equalization
Target Spectra
Designing the Equalizer
Continuous-Time Filters
LMS Adaptation of FIR

Gain and Timing Recovery: AGC & PLL
Where Does Timing Information Come From?
The Effects of ISI
Preliminary Target Determination
Timing Function (Timing Error Detector, TED)
Introduction to Interpolated Timing Recovery (ITR)
Interaction of Feedback Control Loops

Coding
Run-Length Limited (RLL) Code Basics
d=0 Codes for PRML
Introduction to Distance Enhancing Codes
Quantifying Error Events
Maximum Transition Run (MTR) Codes
Rate-1 Codes?
Permuted Architectures
Parity-Assist

PRML, GPR, NPML, NPV, PPNP, DDNP

Methods for Comparing Channels
Introduction to Noise Prediction and Non-Standard    Targets
Noise Whitening Filters
Non-Linear Transition Jitter Noise Model
SNR Definition in Media Noise
Data-Dependent Noise Prediction

Conclusions and Future Trends

The Big Picture
Introduction to LDPC, Turbo Codes,
   Iterative Detection, Turbo Equalization,
   and Low SNR Timing Recovery
Discrete Track Media
The Next dB
Effects of Emerging Market Segments 
New Challenges

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