Motor rotation controlling device

A rotation controlling device for controlling a rotation speed of a motor comprising:

• a rotation detecting means for detecting a rotation speed of a motor;
• a signal processing means for generating a control signal for constantly controlling said motor rotation speed in response to the rotation speed detected by said rotation detecting means;
• a comb-shaped filter means for removing a rotation period component and its harmonic component included in a control signal supplied from said signal processing means;
• a control means for varying a transfer function of said comb-shaped filter means at a transient response and a normal response according to said motor rotation speed;
• a driving means for driving said motor in response to said filtered control signal supplied from said comb-shaped filter means;
• and
• a limit means connected between said signal processing means and said comb-shaped filter means, for limiting the level of said control signal, wherein said limit means comprises:
• a first upper limit value generating means for generating a first upper limit value;
• a second upper limit value generating means for generating a second upper limit value;
• a first lower limit value generating means for generating a first lower limit value;
• a second lower limit value generating means for generating a second lower limit value;
• a first comparing means for comparing a first upper limit value supplied from said first upper limit value generating means with a control signal supplied from said signal processing means;
• a second comparing means for comparing a first lower limit value supplied from said first lower limit value generating means with a control signal supplied from said signal processing means;
• a first switching means for switching a control signal supplied from said signal processing means and a first upper limit value supplied from said first upper limit value generating means and a first lower limit value supplied from said first lower limit value generating means according to logic values of comparing signals supplied from said first and second comparing means;
• a first count means for counting the interval for a comparing signal generated in said first comparing means to keep a predetermined logic state and generating a carry signal when the counted value exceeds a predetermined value;
• a second count means for counting the interval for a comparing signal generated in said second comparing means to keep a predetermined logic state and generating a carry signal when the counted value exceeds a predetermined value;
• a gate means for timing said counter according to logic values of comparing signals supplied from said first and second comparing means;
• and
• a second switching means for switching a second upper limit value supplied from said second upper limit value generating means, a second lower limit value supplied from said second lower limit value generating means and an output of said first switching means to said comb-shaped filter means, according a logic value of carry signals supplied from said first and second count means and an output of said gate means.

A rotation controlling device for controlling a rotation speed of a motor comprising:

• a rotation detecting means for detecting a rotation speed of a motor;
• a signal processing means for generating a control signal for constantly controlling said motor rotation speed in response to the rotation speed detected by said rotation detecting means;
• a comb-shaped filter means for removing a rotation period component and its harmonic component included in a control signal supplied from said signal processing means;
• a control means for varying a transfer function of said comb-shaped filter means at a transient response and a normal response according to said motor rotation speed;
• a driving means for driving said motor in response to said filtered control signal supplied from said comb-shaped filter means;
• and
• a limit means connected between said comb-shaped filter and said driving means, for limiting the level of said control signal, wherein said limit means comprises:
• an upper limit value generating means for generating an upper limit value;
• a first comparing means for comparing a control signal supplied from said signal processing means with an upper limit value supplied from said upper limit value generating means;
• a first switching means for switching a control signal supplied from said signal processing means and an upper limit value supplied from said upper limit value generating means according to a logic state of a comparing signal supplied from said first comparing means;
• a lower limit value generating means for generating a lower limit value;
• a second switching means for switching an output of said first switching means and a lower limit value supplied from said lower limit value generating means to said comb-shaped filter means;
• and
• a second controlling means for making said second switching means select a lower limit value while a predetermined logic state of a comparing signal generated in said first comparing means exceeds a first predetermined interval.

A rotation controlling device for controlling a speed of a drum motor in a video cassette recorder comprising:

• a rotation detecting means comprising a frequency generator head and a phase generator head, said frequency generator head detecting an angular speed of said drum motor and said phase generator head detecting a rotation phase of said drum motor;
• a first signal processing means for generating speed control data for constantly controlling a rotation speed of said drum motor in response to the angular speed detected by said frequency generator speed;
• a comb-shaped filter means for removing a rotation period component and its harmonic component included in said first control data supplied from said first signal processing means;
• a control means for varying a transfer function of said comb-shaped filter means at an initial operation and a normal operation, according to a rotation speed of said drum motor;
• a limit means connected between said comb-shaped filter means and said signal processing means, for limiting said speed control data;
• a second signal processing means for generating phase control data for constantly controlling a rotation phase of said drum motor by said detected rotation phase supplied from said phase generator head;
• an addition means for adding said speed control data and phase control data supplied from said comb-shaped filter means;
• and
• a means for driving said drum motor according to a motor control signal supplied from said digital-analog converting means,
• wherein said limit means comprises:
• an upper limit value generating means for generating an upper limit value;
• a first comparing means for comparing a control signal supplied from said signal processing means with an upper limit value supplied from said upper limit value generating means;
• a first switching means for switching a control signal supplied from said signal processing means and an upper limit value supplied from said upper limit value generating means according to a logic state of a comparing signal supplied from said first comparing means;
• a lower limit value generating means for generating a lower limit value;
• a second switching means for switching an output of said first switching means and a lower limit value supplied from said lower limit value generating means to said comb-shaped filter means;
• and
• a second controlling means for making said second switching means select a lower limit value while a predetermined logic state of a comparing signal generated in said first comparing means exceeds a first predetermined interval.