Rangeless servo notch optimization

A method for placing notch filters in a servo control loop in a disc drive comprising steps of:na) measuring a structural response for the drive; b) calculating an open loop response for the structural response; c) determining a frequency peak in the open loop response; d) calculating a notch filter for the frequency peak; e) placing the notch filter in the control loop; f) recalculating the open loop response; g) repeating steps (c) through (g) until no frequency peaks are determined; and h) changing the gain threshold if no peaks are determined, and repeating steps (c) through (h) until a maximum number of notches has been placed in the control loop.

A test system for setting notch filters in the servo control system control loop of a data storage device, the test system comprising:na memory; and means for detecting resonance peaks in a data storage device open loop response spectrum stored in the memory and dynamically setting a notch filter in the servo control system for each resonance peak sequentially in order of resonance magnitude.

A disc drive servo control system test system for setting notch filters in the servo control system control loop of a disc drive, the test system comprising:na memory module; a resonance detection module for detecting resonance peaks in a disc drive open loop response spectrum stored in the memory; and a dynamic notch filter module for dynamically setting a notch filter in the servo control system for each resonance peak that exceeds a predetermined threshold amplitude in the open loop response in order of resonance peak amplitude.

A method for placing a predetermined number of notch filters in a data storage device servo control system comprising steps of:na) selecting a predetermined frequency range; b) storing a response spectrum of noise generated by the data storage device in the predetermined frequency range in a memory; c) calculating an open loop response for the response spectrum; d) determining whether any noise frequencies in the open loop response exceed a selected gain threshold; e) if there are any noise frequencies that exceed the gain threshold, calculating a notch filter for each noise frequency; f) mathematically applying the notch filter into the servo control system; g) repeating steps (c)-(g) until no noise frequencies exceed the gain threshold; h) select another frequency range; i) if the another frequency range is less than a maximum range, repeat steps (c) through (i); j) reduce the gain threshold; and k) repeat steps (c)-(j) until the predetermined number of notch filters have been placed.

A system comprising:na memory to store information relating to frequency response of a channel, the channel having the frequency response across a frequency range; and a processor to generate a compensation filter for the channel by: (a) storing frequency response information for a portion of the frequency range into the memory; (b) identifying an amplitude specification for frequencies within the portion of the frequency range; (c) identifying frequencies at which an open loop response associated with the channel has an amplitude peak that exceeds the amplitude specification within the portion of the frequency range; and (d) applying a compensation filter comprising one or more notch filters to substantially attenuate the amplitude peak at each of the identified frequencies.

The system of claim 15, further comprising:n(e) repeating the operations (a)—(d) for different portions of the frequency range until the compensation filter includes a maximum number of notch filters or until the entire frequency range has been compensated.

A method to generate a compensation filter for a channel, the method comprising:n(a) providing a channel with a frequency response across a frequency range; (b) storing frequency response information for a portion of the frequency range; (c) identifying an amplitude specification for frequencies within the portion of the frequency range; (d) identifying frequencies at which an open loop response associated with the channel has an amplitude peak that exceeds the amplitude specification within the portion of the frequency range; and (e) applying a compensation filter comprising one or more notch filters to substantially attentuate the amplitude peak at each of the identified frequencies.