Real-time correction of repeatable runout for multiple harmonic frequencies is provided by using convolution of a position error signal, or similar real-time signal, with an impulse response of a specific transfer function, such as the inverse of the disturbance transfer function. Multiple harmonic frequencies can be followed substantially simultaneously to achieve small position error and good tracking misregistration (TMR) performance. The impulse response can be obtained, calculated and stored off-line. The impulse response can be configured to substantially eliminate correction of one or more frequency or frequency ranges. Convolution can be done relatively quickly with proper arrangement of memory.
Convolution based multiple harmonic frequency repeatable runout compensation method and apparatus