JPS645363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an end detection device for a record player for detecting that a pickup provided on a tone arm is tracing a lead-out groove formed at the end side of a sound groove of a record disc. Regarding.

Generally, the lead-out grooves of a record disc are formed with a pitch larger than that of the sound grooves, so the end can be detected by detecting the change in pitch.

Conventionally, the end detection described above has been performed by a position detection device that detects the current horizontal operation position of the tone arm in a record player having an automatic performance function. For example, the structure is such that multiple photoelectric conversion elements detect the transmitted light through slits arranged in a shutter plate that moves together with the tone arm to obtain a position detection signal with a number of pulses corresponding to the amount of movement of the tone arm. In the horizontal position detection device, end detection is performed by detecting a change in the pulse width of the position detection signal.

By the way, in the above-mentioned position detection device, since the conversion characteristics of each photoelectric conversion element used vary depending on each element, the pulse of the obtained position detection signal is This also causes variations in width. Therefore, when end detection is performed by detecting changes in the pulse width of the position detection signal, it is necessary to take measures against the above-mentioned variations in the pulse width.

Therefore, the present invention provides pulses of the position detection signal in a horizontal position detection device that uses a plurality of photoelectric conversion elements to form a position detection signal with a number of pulses corresponding to the amount of horizontal movement of the tone arm. When end detection is performed by detecting a change in width, the influence on the pulse width of the position detection signal due to variations in the photoelectric conversion characteristics of the photoelectric conversion element is removed so that end detection can be performed correctly. horizontal position detection means that outputs two-phase position detection signals with a phase shift of 90 degrees according to the amount of horizontal movement of the tone arm; and reference data generation means that outputs reference time data. , a counting means for counting the number of edges of the two-phase position detection signal outputted from the position detection means, and a counter for counting the number of edges of the two-phase position detection signal, the counting means counting 4N edges (N is a positive integer) of the position detection signal. A counting means for measuring the required time compares the reference time data from the reference data generating means and the output signal from the counting means, and when the output signal from the counting means is smaller than the reference time data, the end is reached. The present invention provides an end detection device for a record player having a novel configuration, characterized in that it includes an end detection means for outputting a detection signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing an embodiment of an electronically controlled record player constructed by applying the present invention.

As shown in the block diagram of FIG. 1, the electronically controlled record player in this embodiment has a tone program controlled by a system control circuit (hereinafter simply referred to as a system controller) 11 having a program control function using a microprocessor or the like. The arm 100 has a horizontal control system and a vertical control system, and the horizontal drive motor 40 in the horizontal control system performs horizontal drive operations such as lead-in and lead-out operations of the tone arm 100, and the vertical control system The tone arm 100 is configured to be vertically operated, such as up and down operations, by a vertical drive motor 50 therein.

A horizontal drive control circuit 20 that supplies a drive current to the horizontal drive motor 40 is program-controlled by a horizontal control signal from the system controller 11, and controls the horizontal drive motor so as to move the tone arm 100 to a desired horizontal position. 40, and speed feedback control of the horizontal drive motor 40 based on a speed detection signal from a horizontal speed detector 60 that detects the horizontal movement speed of the tone arm 100. Further, the horizontal drive control circuit 20 controls the inside hose cancel circuit 1 during performance operation based on a control signal from the system controller 11.
The IFC signal is supplied from 5, and the force for inside hose cancellation during the playing operation is
The horizontal drive motor 40 generates the signal according to the IFC signal. Further, the vertical drive control circuit 30 that supplies a drive current to the vertical drive motor 50 is program-controlled by a vertical control signal from the system controller 11, and moves the tone arm 1 to a desired vertical position.
The vertical drive motor 50 moves the
In addition to controlling the drive of the tone arm 1,
Vertical speed detector 7 that detects the vertical movement speed of 00
Speed feedback control of the vertical drive motor 50 is performed based on the speed detection signal from 0. Further, the vertical drive motor 50 is supplied with a stylus pressure signal from the stylus pressure application circuit 17 during performance operation in response to a control signal from the system controller 11, and generates a force to apply stylus pressure in accordance with this stylus pressure signal. The above vertical drive motor 5
It is generated at 0. The horizontal and vertical operating positions of the tone arm 100 driven and operated by the horizontal drive motor 40 and the vertical drive motor 50 are detected by a horizontal position detector 80 and a vertical position detector 90. Each position detection signal from each of the position detectors 80 and 90 is supplied to the system controller 11 as a data signal. This system controller 11 is pre-installed with control programs for various operation modes of the record player, and executes predetermined program operations selected according to mode command signals from the operation mode setting device 13.
The horizontal position detector 80 and the vertical position detector 9
Each position detection signal from 0 is executed as a data signal, and various control signals are output.

Next, we will discuss the mechanical configuration of this example in the second section.
This will be explained using FIGS. 6 to 6.

First, the tone arm 100 is attached via a support mechanism 120 to the upper end of the center shaft 102, which is rotatably and uprightly installed by an arm base 101 arranged and fixed on the upper panel 131 of the player main body 130. ing. This tone arm 100 has the axis of the support shaft of the support mechanism 120 as a horizontal axis, and the center axis 10
The two axes are perpendicular to each other and are pivotably supported in the vertical direction (vertical direction) and horizontal direction. Tone arm 10 above
The cartridge shell 103 provided at the tip of the playback needle 1 traces the sound groove of the record disc 133 placed on the turntable 132.
A pick-up cartridge 105 equipped with 04 is attached. In addition, the above tone arm 1
A balance weight 106 for balance adjustment is attached to the rear end side of the tone arm 100 so as to be movable and adjustable along the axial direction of the tone arm 100.

A horizontal drive motor 40 for horizontally operating the tone arm 100 includes a magnetic circuit section 43 having a permanent magnet 41 curved in an arc shape around the vertical axis, and a drive coil 44 wound around a bobbin 45. The magnetic circuit section 43 is fixed to the arm base 101 via a fixed arm 141, and the bobbin 45 wound around the drive coil 44 is connected to the tone arm 100 via a rotating arm 142. It is attached to a center shaft 102 that rotates integrally horizontally. The magnetic circuit section 43 includes a frame-shaped yoke 42 having two horizontal rods 42a and 42b curved into an arc shape similar to the permanent magnet 41, and the above-mentioned It is made by fixing a permanent magnet 41. The permanent magnet 41 is magnetized in its upper and lower thickness directions, that is, in the vertical direction. Note that the yoke 442 forms a closed magnetic path through which the magnetic flux generated from the permanent magnet 41 passes. Further, a predetermined interval is provided between the other horizontal rod 42b of the yoke 42 and the permanent magnet 42, and the bobbin 45 around which the drive coil 44 is wound is attached to the horizontal rod 42b.
b, and is arranged so as to be rotatable in the horizontal direction along the horizontal rod 42b. A drive current from the horizontal drive control circuit 20 is passed through the drive coil 44 wound around the bobbin 45 in a direction perpendicular to the direction of the magnetic flux generated from the permanent magnet 41.

The horizontal drive motor 40 having such a configuration has a direction (third direction) of the drive current flowing through the drive coil 44.
Depending on the direction of the arrow a or the direction of the arrow in the figure),
A driving force in the direction of arrow b or arrow in FIG. 3 is generated according to Fleming's left-hand rule, and by applying this driving force to the center shaft 102, the tone arm 100 is moved in the lead-in direction or the lead-out direction. Can be rotated.

The vertical drive motor 50 for vertically operating the tone arm 100 is, in principle, the same as the horizontal drive motor 40 described above, but is arranged vertically. That is, in this example, the fifth
As shown in the figure, a yoke member 52A having an E-shaped longitudinal section
and an I-shaped yoke member 52B, and a pair of permanent magnets 51A and 51B that face each other are fixed to a yoke 52 that faces each other with a vertical rod 52b at the center of the E-shaped yoke member 52A. Part 53
and a drive coil 54 wound around a bobbin 55 which is fitted around the vertical rod 52b and is relatively movable along the vertical rod 52b.
is connected to the center shaft 10 via the rotating arm 143.
2, and a bobbin 55 around which the drive coil 54 is wound is arranged and fixed at the center of a mounting frame 144 provided at the rear end of the tone arm 100. In addition, each permanent magnet 51A, 51B forming the magnetic circuit section 53 and the yoke 52
The vertical rods 52a, 52b, and 52c are curved in an arc shape about the horizontal axis of the support mechanism 120. In addition, each of the above permanent magnets 51A, 5
1B is magnetized in its left and right thickness direction, that is, in the horizontal direction, so that the horizontal magnetic flux generated therefrom flows through a closed magnetic path formed via the yoke 52. moreover,
The drive coil 54 includes a vertical drive control circuit 30.
The drive current from the permanent magnets 51A, 51B
The magnetic flux is caused to flow in a direction perpendicular to the direction of the magnetic flux generated by the magnetic flux.

The vertical drive motor 50 having such a configuration generates a driving force in the direction of arrow c or the direction of the arrow in FIG.
By applying this force, the tone arm 100 can be rotated in the down direction or up direction.

A vertical speed detector 70 for detecting the vertical operation speed of the tone arm 100 driven and operated by the vertical drive motor 50
A generator is constituted by a magnetic circuit section 73 and a detection coil 74, which have the same structure in principle as that of the tone arm 100. The magnetic circuit section 73 connects to the center shaft 10 via the rotating arm 143.
2, and the magnetic circuit section 73 is arranged and fixed at the center of a mounting frame 145 provided on the tone arm 100. This vertical speed detector 70 is
When the tone arm 100 moves in the vertical direction, the detection coil 74 moves in the vertical direction integrally with the tone arm 100 and moves relative to the magnetic circuit section 73, thereby generating a signal according to the moving speed. A level speed detection signal is generated by the detection coil 74. The detection signal obtained from the vertical speed detector 70 is supplied to the vertical drive control circuit 30,
It is used for speed feedback control of the vertical drive motor 50.

Further, a vertical position detector 90 for detecting the vertical operation position of the tone arm 100 driven and operated by the vertical drive motor 50, that is, arm down, arm up, etc., includes a detection coil 94 and a detection coil 94. It is composed of a rod-shaped dust core 92 that can be put in and taken out relatively freely. The detection coil 94 is wound around a cylindrical bobbin 95 on the tone arm 1.
00, and the dust core 92 is attached upright to the rotating arm 143 and is placed at a position below the detection coil 94.

The vertical position detector 90 having such a configuration has a detection coil 9 that corresponds to the vertical operation of the tone arm 100.
The vertical operation position of the tone arm 100 can be detected by the state of change in the inductance of the detection coil 94, which changes according to the relative position between the tone arm 4 and the dust core 92. The vertical position detector 90
The vertical position detection signal obtained from the vertical position detection signal is used for position feedback control of the vertical drive motor 50.

Further, a horizontal speed detector 60 for detecting the horizontal operation speed of the tone arm 100 driven and operated by the horizontal drive motor 40 includes a magnetic circuit section 63 and a detection coil 64 having the same structure in principle as the horizontal drive motor. The magnetic circuit section 63 is fixed to the arm base 101 via the fixed arm 146, and the detection coil 64 is fixed to the arm base 101 via the fixed arm 146.
is connected to the center shaft 10 via the rotating arm 147.
It is attached to 2. This horizontal speed detector 6
0 means that when the tone arm 100 moves in the horizontal direction, the detection coil 64 moves in the horizontal direction integrally with the tone arm 100 and moves relative to the magnetic circuit section 63. The detection coil 64 generates a speed detection signal with a signal level corresponding to the signal level.

The speed detection signal obtained from the horizontal speed detector 60 is supplied to the horizontal drive control circuit 20 and used for speed feedback control of the horizontal drive motor 40.

Furthermore, the horizontal position detector 80 for detecting the horizontal operation position of the tone arm 100 is a sixth horizontal position detector 80.
As shown in the figure, a movable slit plate 81 is attached to the center shaft 102 via a mounting plate 148.
, a fixed slit plate 82 fixed to the arm base 101 and arranged close to and parallel to the movable slit plate 81, and three pairs of light emitting elements 83A disposed opposite to each other with the slit plates 81 and 82 interposed therebetween. ,8
3B, 83C and light receiving elements 84A, 84B, 8
It is composed of 4C. The movable slit plate 81 is formed into a substantially fan shape centered on the vertical axis of the center shaft 102, and a large number of slits 85 are formed at predetermined intervals and pitches along the periphery of the movable slit plate 81, centered on the vertical axis. The elongated holes 86 are arranged in a circular arc shape and have a circular arc shape centered on the vertical axis and a wedge-shaped one end edge 86a. Further, the fixed slit plate 82 is connected to the slit 8 of the movable slit plate 81.
Several slits 87 are formed in two areas opposite to the slits 85 with the same spacing and pitch as the slits 85.
A and 87B are arranged in an arc shape centered on the vertical axis, and slits 88 are formed at positions corresponding to the elongated holes 86 of the movable slit plate 81. Note that the slits 8 formed in two areas of the fixed slit plate 82
The slits 7A and 87B are arranged so as to be shifted from the slits 85 of the movable slit plate 81 by approximately 1/4 of the slit interval λ. Three pairs of light emitting elements 83A, 83 facing each other with the movable slit plate 81 and fixed slit plate 82 in between.
B, 83C and light receiving elements 84A, 84B, 84
Mounting surfaces 89a, 8C are formed parallel to the holder 89 fixed to the arm base 101 via the mounting arm 149 at a predetermined distance.
9b, and are arranged at positions corresponding to the respective slits 87A, 87B, and 88 of the fixed slit plate 82.

In the horizontal position detector 80 having such a configuration, when the tone arm 100 is operated horizontally, the movable slit plate 81 horizontally rotates together with the center shaft 102, and the slit 85 and the elongated hole 86 of the movable slit plate 81 are aligned with each other. Each slit 87 of the fixed slit plate 82
By changing the relative positional relationship with A, 87B, 88, each light receiving element 84A, 84B, 84C
The following position detection signal can be obtained from That is, the light receiving element 84C arranged corresponding to the slit 88 of the fixed slit plate 82 is
The slit 88 is a long hole 86 of the movable slit plate 81.
The light from the light emitting element 83C is received during the period overlapping with the above period, and is used as origin information indicating that the tone arm 100 is at the armrest 134 position, that is, the starting position of the horizontal operation of the tone arm 100. Further, the light receiving elements 84A, 84B arranged corresponding to the respective slits 87A, 87B of the fixed slit plate 82 detect the waveform of the detection signal from one of the light receiving elements 84A as shown in FIG.
In addition, as shown in FIG. 7B, the waveform of the detection signal from the other light receiving element 84B varies depending on the relative positional relationship between the slits 87A, 87B and the slit 85 of the movable slit plate 81. It intermittently receives light from each light emitting element 83A, 83B and outputs a two-phase position detection signal. Since the slits 87A and 87B provided on the fixed slit plate 82 are shifted by 1/4λ, the two-phase position detection signals obtained from each of the light receiving elements 84A and 84B can be detected by the horizontal operation of the tone arm 100. It has a phase difference of ±1/4λ, that is, ±90° depending on the direction, and this phase difference indicates information on the operating direction of the tone arm 100, that is, lead-in and lead-out. Further, the repetition period of the two-phase position detection signal becomes shorter as the horizontal movement speed of the tone arm 100 suddenly increases near the end where the sound groove of the record disc 133 disappears. Information on the lead-out position is shown by changes in the cycle. Further, the two-phase position detection signal is transmitted to each of the slits 87A and 87B whose arrangement positions are fixed relative to the slit 88 of the fixed slit plate 82 which provides information on the starting position of the tone arm 100, and the movable slit plate 81. The signal level changes sequentially due to the relative movement with the slit 85, and each change point in the signal level indicates information about the absolute position of the tone arm 100 in the horizontal direction with respect to the start position.

The pulse width of the two-phase position detection signal is as follows:
For example, compared to the state in which the duty is 50% with no error, as shown by the broken lines in FIGS. 7A and 7B, errors due to variations in the operating characteristics of the light receiving elements 84A and 84B are included.

The system controller 11 performs the following end detection operation based on the two-phase position detection signals shown in FIGS. 7A and 7B. FIG. 8 is a block diagram showing the basic configuration for performing the end detection operation in the system controller 11, in which the two-phase position detection signal is supplied to the counter 2 via the first signal input terminal 1. There is. This counter 2 performs a 4N counting operation to count each edge of the two-phase position detection signal, and causes the data comparator 3 to perform a comparison operation for each carry output signal. The data comparator 3 performs a comparison operation between the time data from the timer 4 and the reference time data from the reference data generator 5.
This is performed for each carry output signal from the timer 4.
When the time data from 1 to 3 is smaller than the reference time data, an end detection speed signal based on the moving speed of the tone arm 100 is output, and a reset signal is supplied to the counter 2 at the end of each comparison operation. There is. Further, the timer 4 repeatedly performs a timer operation each time the counter 2 enters a counting operation state with a count value of "0".
Therefore, assuming that the counter 2 performs N=1, that is, a four-digit counting operation, the timer 4 is set as shown in FIGS. 7A and 7B depending on the initial operating state of the counter 2. Periods T ₁ , T ₂ , T ₃ , T ₄
Time data and Ta corresponding to either
Time data corresponding to any one of Tb, Tc, and Td will be output. The above periods T ₁ , T ₂ ,
The time data corresponding to either T ₃ or T ₄ is obtained during the performance period in which the playback needle 104 is tracing the sound groove of the record disc 133, and the time data corresponding to the above-mentioned Ta, Tb, Tc, and Td Time data corresponding to either one is obtained during a period near the end when the playback needle 104 is tracing the lead-out groove of the record disc 133.

That is, during the performance period, when the counter 2 is reset at the timing _t1 of the rising edge of the detection signal from one of the light receiving elements 84A, the timer 4 is reset at the timing t1 of the rising edge of the detection signal. ₁ to the timing _t5 of the next rising edge, and the counter ₂ is reset at the timing _t2 of the rising edge of the detection signal from the other light receiving element 84B. In this case, the timer 4 outputs time data corresponding to the period T 2 from the rising edge timing t ₂ of the detection signal to the next rising edge timing t ₆ , and furthermore, the counter 2 outputs time data corresponding to the period T ₂ from the rising edge timing t 2 of the detection signal to the next rising edge timing t 6 . When the timer 4 is reset at the timing _t3 of the falling edge of the detection signal from the light receiving element 84A, the timer 4 operates for a period from the timing _t3 of the falling edge of the detection signal to the timing _t7 of the next falling edge. When time data corresponding to T ₃ is output and the counter 2 is reset at timing t ₄ of the falling edge of the detection signal by the other light receiving element 84B, the timer 4 outputs the time data corresponding to the detection signal T 3 . The time data corresponding to the period _T4 from the timing _t4 of the falling edge of ₁ to the timing t8 of the next falling edge is output. Also, during the period near the end,
When the counter 2 is reset at the timing t _a of the rising edge of the detection signal from the one light receiving element 84A, the timer 4 is reset from the timing t _a of the rising edge of the detection signal to the timing t _e of the next rising edge. period until
When time data corresponding to Ta is output and the counter 2 is reset at timing t _b of the rising edge of the detection signal by the other light receiving element 84B, the timer 4 is reset at the rising edge of the detection signal by the other light receiving element 84B. The period Tb from timing t _b to timing t _f of the next rising edge
Further, when the counter 2 is reset at the falling edge timing _tc of the detection signal from one of the light receiving elements 84A, the timer 4 is reset at the falling edge of the detection signal by the one of the light receiving elements 84A. The counter 2 outputs time data corresponding to the period Tc from the edge timing t _c to the next falling edge timing t _g , and furthermore, the counter 2 outputs the timing data of the falling edge of the detection signal by the other light receiving element 84B. When the timer 4 is reset at t _d , the timer 4 is operated for a period T d from the timing t _d of the falling edge of the detection signal to the timing t _h of the next falling edge.
Outputs time data corresponding to .

In the data comparator 3, the reference data generator 5
For example, the size of the time data corresponding to the period indicated by T _R in FIGS. 7A and 7B given by the reference time data from the timer 4 and the time data from the timer 4 is determined. Therefore, an end detection speed signal can be obtained. Note that the end detection speed signal obtained in this manner is a logical product of the end detection position signal based on the information on the absolute position relative to the horizontal start position of the tone arm 100 given by the two-phase position detection signals. It is outputted as an output via the AND gate circuit 6.

In such an end detection operation, the slits 8 that are accurately arranged on the slit plate 81 are
End detection is performed by reading the period of the two-phase position detection signal corresponding to the interval λ of There is no influence due to variations in the operating characteristics of the light receiving elements 84A, 84B.

In addition, like the conventional end detection device, simply
If the end detection is performed by comparing the time corresponding to the edge interval of the two-phase position detection signal with the reference time, the timing of the edge due to changes in pulse width due to variations in the operating characteristics of the light receiving elements 84A and 84B. Since there is a deviation between the two positions, a malfunction may occur in the end detection operation. For example, in the case of a two-phase position detection signal as shown in FIGS. 7A and 7B, the edge interval may become narrower due to the change in pulse width even while the record player is in the playing state. According to the timing in the figure
The end detection speed signal is output between t ₃ and t ₄ or between timings t ₇ and t ₈ . Conversely, even during the period in which the end detection speed signal should be output, the edge interval widens due to the change in the pulse width, resulting in the difference between timings t _b and t _c and timings t _d and t _e in the figure.
It becomes impossible to obtain an end detection speed signal between timings t _f and t _g .

In the embodiment with the above-mentioned configuration,
When the operation mode setter 13 specifies the automatic performance mode and starts the operation, the system controller 11 controls each program of lead-in operation, performance operation, and lead-out operation as follows according to a predetermined program. Do it like this.

First, in the lead-in operation, a position detection signal indicating the origin position information obtained from the light receiving element 84C of the horizontal position detector 80 and each of the light receiving elements 84A, 8 are transmitted.
Based on the two-phase position detection signal indicating the absolute current position information of the tone arm 100 with respect to the origin position obtained from 4B, the system controller 11 is at the starting position where the tone arm 100 is placed on the armrest 134. If the tone arm 100 is at the start position, a horizontal control signal is supplied to the horizontal drive control circuit 20 to immediately move the tone arm 100 in the lead-in direction. When the tone arm 100 reaches the start position, a horizontal control signal is supplied to the horizontal drive control circuit 20 to move the tone arm 100 in the lead-out direction, once return to the start position, and then move it in the lead-in direction.
The system controller 11 compares the target position information indicating the lead-in point given in advance with the absolute current position information of the tone arm 100 based on the two-phase position detection signal from the horizontal position detector 80. A horizontal control signal is generated, and the horizontal drive control circuit 20 continues to drive the horizontal drive motor 40 using this horizontal control signal until the tone arm 100 reaches a predetermined lead-in point. The horizontal drive control circuit 20 is caused to perform position feedback control to stop the tone arm 100 accurately at the lead-in point when the lead-in point is reached. Further, during the lead-in operation as described above, the system controller 11 detects the tone arm 10 based on the position detection signal from the vertical position detector 90.
The vertical drive control circuit 30 performs position feedback control to keep 0 in the up position, and
When the tone arm 100 reaches the desired lead-in point, the vertical drive control circuit 30 sends a vertical control signal to cancel the position feedback control and move the tone arm 100 in the down direction.
is supplied to.

Note that during the lean-in operation of the tone arm 100, the horizontal and vertical movement operations of the tone arm 100 are performed by the horizontal speed detector 60.
Based on each speed detection signal from the vertical speed detector 70, speed feedback control is applied to each drive motor 40, 50 via the horizontal drive control circuit 20 and vertical drive control circuit 30, so that the speed is maintained at a constant speed. The lead-in operation is completed by lowering the playback needle 104 attached to the tone arm 100 to a predetermined lead-in point. In the performance operation performed following such a lead-in operation, each drive motor 40, 5 as described above is operated.
0 position feedback control is canceled and only speed feedback control is performed, and the inside hose cancel circuit 15 and stylus pressure application circuit 17 are activated by the control signal from the system controller 11, and the horizontal drive motor 40 is A drive current that generates force for the hose cancel is supplied from the horizontal drive control circuit 20, and a drive current that provides a predetermined stylus pressure is supplied to the vertical drive motor 50 from the vertical drive control circuit 30. . Therefore, during the performance operation of the tone arm 100, the horizontal drive motor 40 applies a force that cancels the inside hose, and the vertical drive motor 50 applies a force that applies a predetermined stylus pressure. It will be given to you. Furthermore, the tone arm 100 has excellent low-frequency resonance characteristics through speed feedback control of each of the drive motors 40 and 50, and the tone arm 100 has excellent low-frequency resonance characteristics, and can suppress the sound of the record disc 133 even when the record disc 133 warps. The playing operation is performed with a braking force applied so as not to impair the tracing ability of tracing the groove with the playback needle 104.

When the playback needle 104 of the tone arm 100 traces the vicinity of the end of the tone groove on the record disc 133 by performing the above-mentioned performance operation, it is noticed that the pitch of the tone groove near the end becomes larger. As a result, the moving speed of the tone arm 100 becomes faster, and by this change in moving speed, the above-mentioned entrance detection is performed and the lead-out operation is performed. In this readout operation, first, each light receiving element 84 of the horizontal position detector 80 is
End detection is performed by comparing the repetition period of the two-phase position detection signals from A and 84B with a predetermined time in the system controller 11. Immediately after detecting the end, the system controller 11 causes the vertical drive control circuit 30 to drive the vertical drive motor 50 in the upward direction using a vertical control signal, and causes the tone arm 10 to move upward.
Performs 0 up action. And the above Cisco 1
1 provides position feedback control to the vertical drive control circuit 30 to maintain the tone arm 100 in the up state based on the position detection signal from the vertical position detector 90 when the tone arm 100 is raised. At the same time, the horizontal drive control circuit 20 drives the horizontal drive motor 40 according to the horizontal control signal to move the tone arm 100 in the lead-out direction. In this way, tone arm 1
00 is read out and approaches the armrest 134, and when the elongated hole 86 and the slit 88 of the horizontal position detector 80 overlap, the light receiving element 8
Based on the position detection signal from 4C, the drive of the horizontal drive motor 40 is stopped, and the position feedback control of the vertical drive motor 50 is canceled, and the vertical drive motor 5
0 to tone arm 100 and armrest 1
Bring it down to 34. In this way, when the tone arm 100 is placed on the armrest 134, the system controller 11 moves to the vertical position detector 9.
The operation of each control system is stopped in response to the position detection signal from 0, and a series of program operations is completed.

That is, in the embodiment described above, based on the slit 85 of the movable slit plate 81 constituting the horizontal position detector 80, the tone arm 100 is moved in the horizontal direction by each of the light receiving elements 84A, 84B. The two-phase position detection signal with a 90° phase shift obtained according to the amount of
By measuring the time required for counting with the timer 4, the period of the two-phase position detection signal corresponding to the interval λ of the slits 85 is read, and this time data and the reference data generator 5 is compared with the reference time data given by the data comparator 3 to determine the size. When the horizontal movement speed of the tone arm 100 increases near the end where the groove of the record disc 133 disappears, the counting time of the counter 2 measured by the timer 4 becomes smaller than the reference time data. An end detection speed signal is obtained from the data comparator 3.

In this way, by reading the period of the two-phase position detection signal corresponding to the interval λ of the slits 85,
By comparison with the reference time, the tone arm 1
If the end detection is performed by detecting a change in the horizontal movement speed of 00, the end detection can be performed without being affected by variations in the photoelectric conversion characteristics of the respective light receiving elements 84A and 84B of the horizontal position detector 80. It can be carried out.

As is clear from the description of the embodiments described above, according to the present invention, the time required to count 4N edges of two-phase position detection signals with a phase shift of 90° and the reference time are compared. Since end detection is performed by performing the above-mentioned position detection signal, an end detection device for a record player that can perform accurate end detection without being affected by errors due to the operating characteristics of the photoelectric conversion element etc. used to obtain the above-mentioned position detection signal. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a drive control system in an embodiment of an electronically controlled record player to which the present invention is applied. FIG. 2 is a front view of the tone arm portion in the above embodiment. FIG. 3 is a plan view of the tone arm portion as well. FIG. 4 is an external perspective view of the tone arm portion.
FIG. 5 is a longitudinal sectional view of a vertical drive motor portion applied to the above embodiment. FIG. 6 is a plan view of the horizontal position detection portion applied to the above embodiment. FIG. 7 is a waveform diagram showing two-phase position detection signals obtained from the horizontal position detector. FIG. 8 is a block diagram showing an example of the electrical configuration of the end detection device applied to the above embodiment. 2...Counter, 3...Data comparator, 4...Timer, 5...Reference data generator, 11...System controller, 8
0...Horizontal position detector, 90...Vertical position detector, 1
00...Tone arm, 105...Pickup cartridge, 133...Record disk.

Claims (1)

[Claims] 1. Depending on the amount of horizontal movement of the tone arm
horizontal position detection means for outputting two-phase position detection signals with a 90° phase shift; reference data generation means for outputting reference time data; and edge detection means for the two-phase position detection signals output from the position detection means. a counting means for counting the number of pieces; and the counting means detects the edge 4N of the position detection signal.
(N is a positive integer) measuring means for measuring the time required to count the number of pieces; comparing the reference time data from the reference data generating means with the output signal from the measuring means; An end detection device for a record player, comprising: end detection means for outputting an end detection signal when the output signal is smaller than the reference time data. 2. The end detecting means includes data comparing means for comparing the output signal from the measuring means and the reference time data from the reference data generating means, as set forth in claim 1. record player end detection device. 3. The end detection means includes a gate circuit that takes an AND of the end detection position signal given by the two-phase position detection signal from the horizontal position detection means and the output signal from the data comparison means, and The end detection device for a record player according to claim 2, wherein an end detection signal is outputted via a gate circuit.