Patents by Inventor Tsuji Masaaki

Tsuji Masaaki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method and apparatus for optical disk recording capable of reducing settling time and generating an accurate channel clock signal
    Patent number: 7200082
    Abstract: An optical disk recording apparatus includes a first comparator, a second comparator, a third comparator, a selection circuit, a control voltage generator, a voltage control oscillator, and a control circuit. The first comparator compares frequency-divided signals to output an error signal. The second and third comparators compare a signal pre-recorded on an optical disk and the frequency-divided signal to output an error signal and a frequency differential signal. The selection circuit selects any one of the error signals to output the signal selected. The control voltage generator generates a control voltage from the signal from the selection circuit. The voltage control oscillator generates and outputs the write reference clock signal having a frequency corresponding to the control voltage from the control voltage generator. The control circuit controls operations of the selection circuit according to the frequency differential signals.
    Type: Grant
    Filed: November 25, 2003
    Date of Patent: April 3, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuji Masaaki, Ryohsuke Sugiyama
  • Method and apparatus for optical disk recording capable of reducing settling time and generating an accurate channel clock signal
    Publication number: 20040165498
    Abstract: An optical disk recording apparatus includes a first comparator, a second comparator, a third comparator, a selection circuit, a control voltage generator, a voltage control oscillator, and a control circuit. The first comparator compares frequency-divided signals to output an error signal. The second and third comparators compare a signal pre-recorded on an optical disk and the frequency-divided signal to output an error signal and a frequency differential signal. The selection circuit selects any one of the error signals to output the signal selected. The control voltage generator generates a control voltage from the signal from the selection circuit. The voltage control oscillator generates and outputs the write reference clock signal having a frequency corresponding to the control voltage from the control voltage generator. The control circuit controls operations of the selection circuit according to the frequency differential signals.
    Type: Application
    Filed: November 25, 2003
    Publication date: August 26, 2004
    Inventors: Tsuji Masaaki, Ryohsuke Sugiyama