Methods and apparatus for correcting servo signals

Claim 3

A method as claimed in claim 1, wherein: said corresponding waveform of said provided signal is provided with a polarity opposite to the polarity of said electric signal component waveform; said opposite polarity waveform of said provided signal is synchronized with the revolution of said rotating drive; and said error signal component is eliminated with the aid of said provided signal having said synchronized corresponding opposite polarity waveform.

Claim 4

In a servo system wherein a tachometer signal of a servo control of a rotating drive is affected by an electric error signal component having a waveform recurring with each revolution of said rotating drive, the improvement comprising in combination: means for providing an electric signal having a waveform corresponding to said waveform of said signal component; means coupled to said servo system and to said signal providing means for synchronizing said corresponding waveform of said provided signal with the revolution of said rotating drive; and means coupled to said signal providing means and to said servo system for eliminating said error signal component with the aid of said provided signal having said synchronized corresponding waveform.

Claim 5

In a servo system wherein a tachometer signal of a servo control of a rotating drive is affected by an electric error signal component having a waveform recurring with each revolution of said rotating drive, the improvement comprising in combination: means for providing an electric signal having a waveform corresponding to said waveform of said signal component; means coupled to said servo system and to said signal providing means for synchronizing said corresponding waveform of said provided signal with the revolution of said rotating drive; and means coupled to said signal providing means and to said servo system for eliminating said error signal component with the aid of said provided signal having said synchronized corresponding waveform.

Claim 6

A servo system as claimed in claim 3, wherein: said apparatus includes means for providing a version of said synchronized corresponding waveform being opposite in polarity to said waveform of said signal component; and said eliminating means include means for eliminating said error signal component with the aid of said opposite polarity version of said synchronized corresponding waveform.

Claim 7

A servo system as claimed in claim 3, wherein: said synchronizing means include means for sensing revolutions of said rotating drive, and means connected to said revolution sensing means and to said corresponding waveform providing means for synchronizing said corresponding waveform providing means in response to said sensed revolutions.

Claim 8

A servo system as claimed in claim 3, wherein: said corresponding waveform providing means include a variable waveform generator.

Claim 9

A servo system as claimed in claim 6, wherein: said synchronizing means include means connected to said waveform generator for synchronizing said variable waveform generator.

Claim 10

A servo system as claimed in claim 6, wherein: said synchronizing means include means for sensing revolutions of said rotating drive, and means connected to said revolution sensing means and to said variable waveform generator for synchronizing said waveform generator in response to said sensed revolutions.

Claim 13

A method as claimed in claim 9, wherein: said corresponding waveform is provided with a polarity opposite to the polarity of said electric error signal component waveform; said opposite polarity waveform of said provided signal is synchronized with the revolution of said rotary drive; and said zero crossovers of said tachometer signal are modulated with said synchronized opposite polarity waveform to eliminate said electric error signal component.

Claim 14

In a servo system wherein a tachometer signal having a frequency varying as a function of angular velocity of a rotary drive is affected by an electric error signal component having a waveform recurring with each revolution of said rotary drive, the improvement comprising in combination: means for detecting zero crossovers of said tachometer signal; means for counting down said tachometer signal for a division of said frequency; means connected to said counting down means for generating in response to said counted-down tachometer signal a waveform corresponding to said waveform of said error signal component; means connected to said counting down means for synchronizing said corresponding waveform with the revolution of said rotary drive; and means connected to said detecting means for modulating said zero crossovers of said tachometer signal with said synchronized waveform to eliminate said electric error signal component.

Claim 15

In a servo system wherein a tachometer signal having a frequency varying as a function of angular velocity of a rotary drive is affected by an electric error signal component having a waveform recurring with each revolution of said rotary drive, the improvement comprising in combination: means for detecting zero crossovers of said tachometer signal; means for counting down said tachometer signal for a division of said frequency; means connected to said counting down means for generating in response to said counted-down tachometer signal a waveform corresponding to said waveform of said error signal component; means connected to said counting down means for synchronizing said corresponding waveform with the revolution of said rotary drive; and means connected to said detecting means for modulating said zero crossovers of said tachometer signal with said synchronized waveform to eliminate said electric error signal component.

Claim 16

A servo system as claimed in claim 11, wherein: said generating means include means for providing said corresponding waveform with a polarity opposite to the polarity of said electric error signal component waveform; and said modulating means include means for modulating said zero crossovers of said tachometer signal with said opposite polarity waveform to eliminate said electric error signal component.