Apparatus for controlling the rotation of a rotating body in a recording and/or reproducing apparatus

An apparatus for controlling the rotation of a rotating body in a recording and/or reproducing apparatus comprising:

• means including a first DC motor for rotating a capstan;
• first detecting means for detecting the rotational speed of said capstan, interrelatedly with the rotation of said first DC motor, said first detecting means being responsive to an electrical signal of a frequency of n.sub.1 times (where n.sub.1 >>
• 1) said rotational speed;
• first error signal forming means for producing a first error signal having a magnitude which varies in accordance with the advance or the lag of the phase of the output of said first detecting means;
• means including a second motor for rotating a rotary head;
• second detecting means for detecting a signal which varies responsive to the rotational phase of the rotary head which is rotated by said second motor;
• second error signal forming means for producing a second error signal by comparing the output signal of said second detecting means with a reference signal;
• control signal forming means for producing a control signal by combining said first and second error signals;
• and
• means for controlling the rotation of said first DC motor in response to the control signal from said control signal forming means,
• said driving rotation controlling means of the DC motor comprising:
• a circuit for generating an AC signal having a constant period and constant amplitude,
• a circuit for superposing said AC signal from said AC signal generating circuit and a control signal from said control signal forming means and for slicing said superposed signal at a specific level,
• a driving amplification circuit means for switching on or off in response to the signal thus sliced and for producing a rectangular wave output, and
• a circuit means for smoothing the output of said driving amplification circuit to produce a smoothed DC voltage and applying said voltage to the first DC motor.

An apparatus for controlling the rotation of a rotating body in a recording and/or reproducing apparatus comprising:

• means including a DC motor for rotating a body;
• rotational phase detection means for detecting a first electrical signal having a phase which corresponds to the rotational phase of the rotating body;
• a source of a reference pulse signal;
• phase discriminating means comprising trapezoidal wave generator means responsive to the first electrical signal for generating a trapezoidal signal in synchronism with the first electrical signal, phase comparator means for comparing the phase of the trapezoidal wave signal with the phase of the reference pulse signal to produce an output signal in accordance with the phase difference between the trapezoidal wave signal and the reference pulse signal, and holding means for holding the output signal of said phase comparator means to produce a first error signal;
• rotational speed detection means for detecting a second electrical signal having a frequency which varies as a function of the rotational speed of the rotating body, said second electrical signal having a frequency which is n.sub.1 times the rotational speed;
• frequency discriminating means comprising phase shifting means responsive to the second electrical signal for causing a lag in the phase of the second electrical signal, said lag varying in accordance with the difference between the frequency of the second electrical signal and a predetermined frequency when the frequency of the second electrical signal is higher than the predetermined frequency and for advancing the phase of the second electrical signal in accordance with the difference between the predetermined frequency and the frequency of the second electrical signal when the frequency of the second electrical signal is lower than the predetermined frequency, first NAND circuit means for providing an output signal responsive to a coincidence between the output of said phase shifting means and the second electrical signal, first phase inverting means for inverting the phase of the second electrical signal, second phase inverting means for inverting the phase of the output signal of said phase shifting means, second NAND circuit means for providing an output signal responsive to a coincidence between the output of the first and second phase inverting means, and smoothing means for smoothing the combined outputs of the first and second NAND circuit means to produce a second error signal;
• control signal forming means for producing a control signal by combining the first and second error signals;
• oscillator means for generating an AC signal having a periodically varying amplitude and having the predetermined frequency;
• slicing circuit means responsive to the control signal and to the AC signal for slicing a superimposition signal of the control signal and the AC signal at a specific level;
• switching amplifier means having an output current responsive to the output signal of said slicing circuit means;
• and
• filter means for smoothing the output of said switching amplifier means to produce a smooth DC voltage and for applying the DC voltage to said DC motor.

An apparatus for controlling the rotation of a rotating body in a recording and/or reproducing apparatus comprising:

• means including a DC motor for rotating a body;
• rotational phase detection means for detecting a first electrical signal having a phase which corresponds to the rotational phase of the rotating body;
• a source of a reference pulse signal;
• phase discriminating means comprising trapezoidal wave generator means responsive to the first electrical signal for generating a trapezoidal wave signal in synchronism with the first electrical signal, phase comparator means for comparing the phase of the trapezoidal wave signal with the phase of the reference pulse signal to produce an output signal in accordance with the phase difference between the trapezoidal wave signal and the reference pulse signal, and holding means for holding the output signal of said phase comparator means to produce an error signal;
• rotational speed detection means for detecting a second electrical signal having a frequency which varies as a function of the rotational speed of the rotating body, said second electrical signal having a frequency which is n.sub.1 times the rotational speed;
• frequency discriminating means comprising phase shifting means including a transistor having a collector electrode connected to a power source through a parallel combination of a coil and a capacitor, an emitter electrode connected to ground through a resistor and a base electrode having a second electrical signal supplied thereto, and means for applying the error signal to the emitter electrode to change the inductance of the coil whereby an output signal appears at the collector electrode with a phase which is shifted corresponding to the level of the error signal in reference to the second electrical signal, first NAND circuit means having an output signal responsive to a coincidence of an output from said phase shifting means and the second electrical signal, first phase inverting means for inverting the phase of the second electrical signal, second phase inverting means for inverting the phase of the output signal of said phase shifting means, second NAND circuit means having an output signal responsive to a coincidence of the first and second phase inverting means, and smoothing means for smoothing the combined outputs of the first and second NAND circuit means to produce a control signal;
• oscillator means for generating an AC signal having a periodically varying amplitude and having the predetermined frequency;
• slicing circuit means responsive to the control signal and to the AC signal for slicing a superimposition signal of the control signal and the AC signal at a specific level;
• switching amplifier means having an output current in accordance with the output signal of said slicing circuit means;
• and
• filter means for smoothing the output of said switching amplifier means to produce a smooth DC voltage and for applying the DC voltage to said DC motor.