Abstract:
Disclosed is an audio reproduction apparatus for reproducing music information recorded on a digital disk. This apparatus includes a rotatable body, a detection section for detecting a rotational state of the rotatable body, and a processing section for processing the music information to be reproduced in accordance with the rotational state detected by the detection section.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a system for reproducing information such as music recorded on a compact disc (CD)(hereinafter called digital disc). 
     In the LP record player, the tempo, pitch and tone of the reproduced music can be variously changed by manually changing the rotating speed of the turntable of the player. 
     For example, in a discotheque a disc jockey operates the turntable to produce the above described effect. 
     However, in the present time, music is generally recorded on the disc such as CD. 
     Since the reproducing device for the CD comprises a plurality of complicated components, it is impossible to manually change the reproducing condition unlike the LP record player. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a reproducing system which may change the music reproducing condition of the digital disc. 
     According to the present invention, there is provided a system for reproducing music information recorded on a disc, comprising, a reproducing system for reproducing music recorded on a digital disc, having a spindle motor for rotating a turntable, a rotating dial to be rotated by a user, detecting means for detecting a rotating condition of the rotating dial, processing means responsive to a detected rotating condition for processing reproduced music. 
     The processing means is provided for delaying the reproduced music information in accordance with the detected rotating condition, and for changing the pitch of the reproduced music information in accordance with the detected rotating condition, and for changing a frequency range of the reproduced music information in accordance with the detected rotating condition. 
     The processing means is provided for returning a processed music information to an initial condition when the rotating dial is stopped. 
     The rotating condition comprises an amount of rotation and rotating direction. 
     The delaying operation comprises the repeating of the increasing and reducing of the delay time. 
     The pitch is changed by changing the rotating speed of the spindle motor. 
     The frequency range is changed by shifting a frequency range of a band pass filter. 
    
    
     These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a block diagram showing a reproducing system according to an embodiment of the present invention; 
     FIG. 2 is a perspective view of a pulse encoder; 
     FIG. 3 is a rotating condition detecting circuit; 
     FIG. 4 is a timing chart showing detected signals of light receiving elements. 
     FIG. 5 is a timing chart showing the signals. 
     FIG. 6 is a block diagram of an effect producing system. 
     FIG. 7 is a graph showing the relationship between the amount θ of the rotation and the delay time of the JOG dial. 
     FIGS. 8 a  to  8   c  are waveforms showing the changing of the pitch. 
     FIG. 9 is a graph showing the relationship between rotating direction of the JOG dial. 
     FIG. 10 is a graph showing the relationship between the amount θ of rotation and the cutoff frequency. 
     FIGS. 11 a  and  11   b  are graphs showing the change of band pass filter ranges; 
     FIGS. 12 through 15 are flowcharts showing operation of the system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the reproducing system of the present invention comprises a system controller A for controlling the whole of the system, a reproducing system B, a manipulating section C and a display D. 
     The system controller A has a microprocessor unit (MPU) For performing a system program, and controls the reproducing system B and display D in accordance with the user&#39;s operation of the manipulating section C. 
     The reproducing system B comprises a spindle motor  2  for rotating a CD  1 , a pickup  3 , a PLL (phase-locked loop)  4 , a signal processing circuit  5 , a digital signal processor (DSP)  6 , a D/A converter  7 , and an output circuit  8 . 
     The PLL  4  derives a synchronizing signal from a reproduced RF signal S 1  and produces a synchronizing clock S 2  for reproducing which synchronizes the former synchronizing signal with the frequency and phase designated by a speed control signal SC fed from the system controller A. 
     The signal processing circuit  5  produces a spindle servo control signal, focus servo control signal, and tracking servo control signal based on the synchronizing clock S 2 , and thereby the spindle motor  2  and the pickup  3  are controlled. 
     Furthermore, the signal processing circuit  5  produces an audio-data S 3  by separating a frame synchronizing pattern from the reproduced RF signal S 1 , and by processing the EFM (Eight to Fourteen Modulation) decoding, error correction and others, and feeds the audio-data to the digital signal processor  6 . 
     The digital signal processor  6  processes the audio-data S 3  in accordance with an effect control signal EC to produce a converting audio-data S 4  which is applied to the D/A converter  7  to convert the signal to an analogue signal. Thereby the output circuit  8  produces an analogue audio signals S 5 . 
     In the operating section C, there is provided a volume  9  comprising a slide resistor  9   a  and a slide knob  9   b , and JOG dial  10 , and a JOG push buttons  11  through  17 . 
     The slide resister  9   a  is connected between a source Vcc and a ground GND. The volume  9  outputs a divided voltage Vs in accordance with the position of the slide knob  9   b . An A/D converter  18  converts the voltage Vs to a digital data DVs which is applied to the system controller A. 
     The system controller A applies a speed control signal SC having a frequency and phase corresponding to the digital data DVs to the PLL circuit  4 . The PLL circuit  4  produces the synchronizing clock S 2  based on the speed control signal SC. The signal processing circuit  5  controls the spindle motor  2  and the pickup  3  in accordance with the synchronizing clock S 2 . Thereby the rotating speed of the CD  1  is controlled in dependency on the position of the knob  9   b.    
     When the knob  9   b  is positioned at a home position shown in FIG. 1, the rotating speed of the CD  1  is set at the ordinary speed, and the speed increases toward the ground and reduces toward the Vcc. 
     The changing range of the rotating speed is ±10% of the ordinary rotating speed. 
     The JOG dial  10  has a recess  10   a  for indicating the angular position of the dial  10 . 
     Under the JOG dial  10 , an optical pulse encoder  19  is provided for detecting the angular speed, amount of rotation, and rotating direction of the JOG dial  10  to produce detected signals SR which is fed to the system controller A. 
     Referring to FIG. 2 showing the pulse encoder  19 , the pulse encoder comprises a rotating circular plate  20  fixed to a rotating shaft  10   b  of the JOG dial  10 , a fixed plate  21  opposite to the circular plate  20 , and a light emitting element  22  and light receiving elements  23  and  24  opposite to the light emitting element  22 , interposing the rotating plate  20  and the fixed plate  21 . 
     The encoder  19  has a circuit shown in FIG. 3, which comprises an EXOR gate  25  and a D-type flip-flop  26  which are connected to output terminals of the light receiving elements. 
     There are provided a plurality of slits  20   a  circularly formed in the rotating plate  20 , and a plurality of slits  21   a  formed in the fixed plate  21 , each corresponding to an opposite slit  21   a.    
     The light receiving elements  23 ,  24  receive light beams passing through slits  20   a  and  21   a  and the circuit of FIG. 3 produces the signal SR comprising a rotating direction signal Sdr and an angular speed signal Srt as described hereinafter in detail. 
     FIG. 4 shows a timing chart showing detected signals Sa and Sb of the light receiving elements  23 ,  24 . 
     FIG. 5 shows a timing chart showing the signals Sa, Sb, Sdr and Srt. 
     When the JOG dial  10  is rotated in the clockwise direction (+), the signal Sa generates earlier than the signal Sb. When the JOG dial  10  is rotated in the counterclockwise direction, the signal Sb generates earlier than the signal Sa. Consequently, the rotating direction signal Sdr is “0” in the clockwise direction, and the direction signal Sdr is “1” in the counterclockwise direction. The angular speed dependent on the speed signal Srt is detected by counting the number of the output “1” of the EXOR gate  25 . 
     Referring back to FIG. 1, the push button  11  is a start button, push button  12  is a cue button for designating a start position, and the button  13  is a master tempo button. When the button  13  is pushed, if the rotating speed is changed by operating the knob  9   b , the pitch of the reproduced music does not change. 
     The button  14  is a JET effect button for generating a sound like a jet plane by operating the JOG dial  10 , the button  15  is a ZIP effect button for changing the pitch of the reproduced music in accordance with the operation of the JOG dial  10 . The button  16  is a WAH effect button for increasing or decreasing the volume of a high frequency or low frequency range of the reproduced sound in accordance with the operation of the JOG dial  10 . The button  17  is a HOLD effect button. When the button  17  is depressed, the reproducing conditions by the buttons  14 ,  15 ,  16  are held, and when the button is not operated, the reproducing conditions gradually return to original conditions. 
     The composition for producing above described effects with the buttons  14  through  17  is described hereinafter with reference to FIGS. 6 to  11 . 
     Referring to FIG. 6, a JET effect producing system J operated by the JET button  14  comprises a delay circuit  30  for delaying the audio data S 3  from the signal processing circuit  5 , a delay time coefficient circuit  31  for setting a delay time Td for the delay circuit  30 , a gain control circuit  32  for reducing the audio data S 3  to a half level, a gain control circuit  33  for reducing the delayed audio data S 31  to a half level, and an adder  34  for adding audio data S 30  and S 32  from gain control circuits  32  and  33 . 
     The delay circuit  30  delays the audio data by the delay time Td in accordance with a coefficient fed from the delay time coefficient circuit  31  when the JET button  14  is depressed. 
     The delay time coefficient circuit  31  stores delay time coefficient designated by the control signal EC from the system controller A. 
     The system controller A is adapted to produce the control signal EC as the delay time coefficient data in accordance with the amount θ of rotation and rotating direction of the JOG dial  10 . 
     FIG. 7 is a graph showing the relationship between the amount θ of rotation and the delay time Td of the JOG dial  10 . The delay time Td increases and decreases at every 720° rotation of the JOG dial  10  in plus and minus directions. 
     By adding the delayed audio data S 32  and the not delayed data S 30 , a modulated audio data S 24  is produced (FIG.  6 ), thereby producing sounds like sounds of the jet plane. 
     Referring to FIG. 6, a ZIP effect producing system Z operated by the ZIP button  15  comprises a pitch shifter  35  receiving the audio data S 24  from the adder  34 , and a pitch coefficient circuit  36 . 
     The system controller A applies a pitch coefficient data to the pitch coefficient circuit  36  by the control signal in accordance with the amount θ of rotation and the rotating direction of the JOG dial  10 . 
     The pitch shifter  35  changes the pitch Hp of the audio data S 24  based on the pitch coefficient fed from the pitch coefficient circuit  36 . 
     FIG. 8 shows waveforms for the changing of the pitch. FIG. 8 a  shows an original pitch of the audio data S 24 , FIG. 8 b  shows increased pitch in the clockwise direction of the JOG dial  10 , and FIG. 8 c  shows reduced pitch in the counterclockwise direction. 
     FIG. 9 is a graph showing the relationship between the rotating direction of the JOG dial  10 . When the JOG dial  10  is rotated in the clockwise direction (+), the pitch increases 1 octave at every predetermined amount θ, and when the JOG dial is rotated in the counterclockwise direction (−), the pitch reduces 1.5 octave at every amount θ. 
     Referring to FIG. 6, a WAH effect producing system W with the WAH button  16  comprises a low pass filter  27  which can change a cutoff frequency fCH of a high frequency range, a high pass filter  28  which can change a cutoff frequency fCL of a low frequency range of an audio data S 25 , and a filter coefficient circuit  29 . 
     The system controller A applies a filter coefficient data to the filter coefficient circuit  29  based on the amount θ and the rotating direction of the JOG dial  10 . 
     FIG. 10 is a graph showing the relationship between the amount θ of the rotation and the cutoff frequency. 
     When the JOG dial  10  is rotated in the clockwise direction, increases with the amount θ of rotation. When the JOG dial is rotated in the counterclockwise direction the cutoff frequency fCH gradually decreases with the amount θ. 
     FIGS. 11 a  and  11   b  show shifting conditions of the cutoff frequencies fCH, fCL. When the rotation of the JOG dial  10  is stopped, the cutoff frequency is shifted toward a condition passing through the filter. 
     The operation of the system will be described hereinafter with reference to FIGS. 12 through 15. 
     Referring to FIG. 12, at a step S 100  it is determined whether JET effect button  14  is depressed. When the button is not depressed, the delay coefficient Xds corresponding to the delay time Td=0 is fed to the digital signal processor  6  (step S 101 ). 
     If yes, the amount Δθ of the rotation of the JOG dial for a predetermined time is detected at the pulse encoder  19  at a step S 102 . The amount θ of the rotation is stored in a memory (step S 103 ). At a step S 104 , it is determined whether the amount θ is zero. If no, and the HOLD effect button  17  is depressed (step S 400 ), the amount Δθ is stored in a memory (step S 401 ), and a hold process is carried out (step S 402 ). If the HOLD effect button is not depressed at the step  400 , a delay time Td corresponding to the amount θ is obtained (step S 105 ), and a delay time coefficient Xd corresponding to the delay time Td is set (step S 106 ). 
     When the amount θ is zero at the step S 104 , it is determined whether the HOLD effect button is depressed at a step S 107 . If the button is not depressed and the delay time is not zero at a step S 108 , a time Tdr necessary to make the delay time Td zero is calculated (S 109 ). A delay time coefficient Xdr corresponding to the delay time Tdr is fed to the digital signal processor  6  (step S 110 ). 
     Referring to FIG. 13, at a step S 200 , it is determined whether the ZIP effect button  15  is depressed. When the button is not depressed, a pitch coefficient Yps corresponding to an initial pitch Hps is fed to the digital signal processor  6  (step S 201 ). 
     If yes, the amount Δθ of the rotation of the JOG dial for a predetermined time is detected at the pulse encoder  19  at the step S 202 . The amount θ of the rotation is stored in a memory (step S 203 ). At a step S 204 , it is determined whether the amount θ is zero. If no, a pitch Hp corresponding to the amount θ is obtained (step S 205 ). A pitch coefficient Yp corresponding to the pitch Hp is obtained and is set (step S 206 ). 
     When the amount θ is zero, it is determined whether the HOLD effect button is depressed at a step S 207 . If the button is not depressed, and the pitch Hp is not equal to the initial pitch Hps at a step S 208 , a return pitch Hpr necessary to make the pitch Hp the initial pitch Hps is calculated (step S 209 ). A pitch coefficient Ypr corresponding to the pitch Hpr is fed to the digital signal processor  6  (step S 210 ). 
     Referring to FIG. 14, at a step S 300  it is determined whether WAH effect button  16  is depressed. When the button is not depressed, the filter coefficient Zs for making the filters to passing through conditions Fs(f) is fed to the digital signal processor  6  (step S 301 ). 
     If yes, the amount θ of the rotation of the JOG dial for a predetermined time is detected at the pulse encoder  19  at a step S 302 . The amount θ of the rotation is stored in a memory (step S 303 ). At a step S 304 , it is determined whether the amount θ is zero. If no, a filter characteristic F(f) corresponding to the amount θ is obtained (step S 305 ), and a filter coefficient Z corresponding to the filter characteristic F(f) is set (step S 306 ). 
     When the amount θ is zero at the step S 304 , it is determined whether the HOLD effect button  17  is depressed at a step S 307 . If the button is not depressed and the filters are not in passing through conditions at a step S 308 , a return filter characteristic Fr(f) necessary to make the filter characteristic F(f) to the passing through conditions Fs(f) is calculated (step S 309 ). A filter coefficient Zr corresponding to the filter characteristic Fr(f) is fed to the digital signal processor  6  (step S 310 ). 
     Referring to FIG. 15, at a step S 405 , it is determined whether JET effect button  14  is depressed. When the button is not depressed, it is determined whether the ZIP effect button  15  is depressed at a step  409 . 
     If the button  14  is depressed, the amount Δθ of the rotation of the JOG dial for a predetermined time is detected at the pulse encoder  19  and the amount θ of the rotation is stored in a memory (step S 406 ). A delay time Td corresponding to the amount θ is obtained (step S 407 ), and a delay time coefficient Xd corresponding to the delay time Td is set (step S 408 ). When the ZIP effect button  15  is depressed, a pitch Hp corresponding to the amount θ is obtained (step S 410 ). 
     A pitch coefficient Yp corresponding to the pitch Hp is obtained and set (step S 411 ). 
     When the WAH effect button  16  is depressed at a step S 412 , a filter characteristic F(f) corresponding to the amount θ is obtained (step S 413 ), and a filter coefficient Z corresponding to the filter characteristic F(f) is set (step S 414 ). 
     From the foregoing, it will be understood that it is possible to change the reproduced music to various moods only by rotating the dial. 
     While the invention has been described in conjunction with preferred specific embodiment thereof, it will be understood that this description is intended to illustrate and not limit the scope of the invention, which is defined by the following claims.