Compensation apparatus for a servo system with periodic command signals
Variable characteristic filters
Head positioning mechanism for rotating disk data storage system
Video signal recording apparatus Patent #: 4656529
ApplicationNo. 321108 filed on 03/09/1989
US Classes:318/621, Lead or lag networks318/662, Variable capacitor systems360/77.05By servo signal component from carrier surface separate from information signal bearing surface
ExaminersPrimary: Shoop, William M. Jr.
Assistant: Bergmann, Saul M.
Attorney, Agent or Firm
Foreign Patent References
International ClassG05B 006/02
Foreign Application Priority Data1988-03-10 JP
AbstractA notch filter, used in a servo loop, for dampening a mechanical resonance of a mechanism to be servo-controlled, including a serial T-type filter with a capacitor-resistor (CR) network having a serial connection of a first, second and third capacitors connected between an input terminal of the serial T-type filter and an output terminal of the Cr network; a first resistor connected between a return terminal of the CR network and an interconnection of the first and second capacitors; a second resistor connected between the return terminal and an interconnection of the second and third capacitors; and a third resistor connected in parallel to the three serial capacitors. A notch frequency of the notch filter is adjusted by varying the resistance values of the first and second resistors. The first and second resistors may include fixed and/or potentiometer-type variable resistors. An output from the CR network may be divided to be fed back to the return terminal to provide feedback. Amplifiers may be added to the output of the CR network and the feedback circuit to provide isolation. The first and second resistors for adjusting the notch frequency may be separately installed in a detachable disk unit which includes the mechanism to be servo-controlled. As a result, the notch frequency can be efficiently adjusted by replacing only two fixed resistors or by adjusting the variable resistor, and the cost of the disk unit can be reduced.