Cross-Talk Measurement Circuit for Array Reader Magnetic Storage
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Solution Overview
Problem
In array reader magnetic recording systems, cross-talk between signals at read heads and transmission lines degrades system performance, necessitating effective measurement and characterization to mitigate noise and identify sub-optimal readers during fabrication.
Innovation Solution
An apparatus with multiple read heads, preamplifiers, and a cross-talk measurement circuit measures and characterizes cross-talk by driving a signal on one read head while others are un-driven, using pseudo-random bit sequences and de-biasing to isolate cross-talk effects, allowing for noise cancellation and identification of sub-optimal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-talk measurement is performed in array reader magnetic recording system, then measurement precision of cross-talk transfer function is improved, but device complexity increases due to additional measurement circuits and procedures
Solution Approach 1:
The system uses its own read heads and preamplifiers to measure cross-talk, rather than requiring external specialized measurement equipment. The measurement is performed by the system components themselves during normal operation or calibration modes, eliminating the need for separate measurement devices and reducing overall system complexity.
Solution Approach 2:
A measurement circuit acts as an intermediary between the preamplifiers and the control system, enabling cross-talk measurement without requiring direct modification of the preamplifier design. This intermediary circuit simplifies the measurement process by providing a dedicated interface for signal analysis while maintaining the independence of the original read channels.
2Productivity
If multiple read heads are used in array reader, then productivity of data reading is improved, but cross-talk between signals increases degrading system performance
Solution Approach 1:
The system measures cross-talk transfer functions between read heads and uses this measurement data to configure noise cancellation circuits. The measured cross-talk characteristics provide feedback that enables active compensation, allowing the system to maintain high productivity with multiple read heads while canceling the harmful cross-talk effects through signal processing.
Solution Approach 2:
The cross-talk signals that initially degrade performance are measured and characterized, then converted into useful information for noise cancellation. By measuring the cross-talk transfer functions, the system transforms the harmful cross-talk into a known disturbance that can be actively canceled, thereby improving overall system performance while maintaining the benefits of multiple read heads.
3Reliability
If noise cancellation is implemented, then system performance is improved, but device complexity increases due to additional processing circuits
Solution Approach 1:
Cross-talk transfer functions are measured and stored in advance during system initialization or calibration. This preliminary measurement allows the noise cancellation circuits to be pre-configured with accurate cross-talk characteristics, enabling effective noise cancellation during normal operation without requiring complex real-time adaptation or additional processing complexity during data reading.
Data Source
AI summary
An apparatus for measuring cross-talk in an array reader magnetic storage system includes an array reader with multiple read heads operable to read data from a magnetic storage medium, a first preamplifier connected to a first read head, a second preamplifier connected to a second read head, and a cross-talk measurement circuit connected to the first preamplifier and to the second preamplifier, operable to measure cross-talk between a first signal from the first read head and a second signal from the second read head.