Data and servo sampling in synchronous data detection channel

摘要

An analog-to-digital converter circuit in a sampling data detection channel of a disk drive synchronously samples user data in the data track areas at a first quantization resolution and samples servo bursts from the spoke areas at a second quantization resolution effectively greater than said first quantization resolution. An offset circuit provides a predetermined analog offset signal to a combining circuit which combines it with an incoming analog signal to provide a composite signal during a spoke servo burst sampling interval. An analog-to-digital converter samples the composite signal during the servo spoke burst sampling interval, and synchronously samples the analog signal during a user data sampling interval. A digital averaging circuit averages the servo spoke samples over a predetermined averaging interval to provide averaged burst samples having increased bit resolution.