Constant velocity track jump servo system for disc players

Claim 2

A record disc reproducing apparatus comprising: a pick-up device for reading data from a disc; means for moving said pick-up device radially across said disc, said moving means including a first phase compensation circuit with a first phase compensation characteristic for stabilizing the pick-up device in a reproducing mode; means for producing a velocity signal corresponding to a moving velocity of said pick-up device; kick signal generating means for comparing said velocity signal to a reference velocity signal and generating a kick signal used to control said moving means so as to cause said velocity signal to approach a value of said reference velocity signal; a second phase compensation circuit having a second characteristic different from said first characteristic, said second phase compensation circuit being responsive to said kick signal and having an output which is connected to an input of said first phase compensation circuit in a search mode, so as to eliminate an effect of the phase compensation of said first phase compensation circuit when the pick-up device is in said search mode; and control means for selectively applying said kick signal to said moving means during said search mode to cause said pick-up device to move at a velocity corresponding to said reference velocity signal.

Claim 3

Apparatus according to claim 1, wherein said control means includes means for determining a number of tracks crossed as said moving means moves said pick-up device and means for deenergizing said moving means when a desired number of tracks have been crossed.

Claim 4

A record disc reproducing apparatus according to claim 2, wherein said kick signal generating means comprises a reference velocity voltage supply for supplying a first reference velocity signal having a high voltage value and a second reference velocity signal having a low voltage value, respectively, and comparing means for comparing said velocity signal to said first reference velocity signal for producing a first comparison result used for generating a first kick signal which is applied to said moving means to drive said pick-up device at a high speed until said pick-up device comes within a predetermined number of tracks from a desired track, and for comparing said velocity signal to said second reference velocity signal for producing a second comparison result used for generating a second kick signal which is applied wot said moving means to drive said pick-up device at a low speed until said desired track is reached.

Claim 5

Apparatus according to claim 1 wherein said control means includes means for determining a number of tracks crossed as said moving means moves said pick-up device, and means for causing said moving means to apply a force to said pick-up device opposing movement of said pick-up device when said control means determines that said pick-up device is within a predetermined number of tracks from a desired track.

Claim 6

A record disc reproducing apparatus according to claim 1, wherein an input of said second phase compensation circuit is connected to an output of said kick signal generating means and further comprising a switch for connecting said output of said second phase compensation circuit to said input of said first phase compensation circuit, during said search mode.

Claim 7

A record disc reproducing apparatus according to claim 1, wherein an input of said second phase compensation circuit is connected to an output of said first phase compensation circuit and further comprising a switch and a subtractor, said switch for connecting an equalizing output of said second phase compensation circuit to a first input of a subtractor, said subtractor receiving said kick signal at a second input thereof during said search mode, an output of said subtractor being provided to said first phase compensation circuit so as to form, during said search mode, a feedback path comprising said first and second phase compensation circuits, said switch and said subtractor.

Claim 8

Apparatus as in claim 1, wherein said moving means further comprises tracking means, for tracking said pickup device and producing an error signal indicative of said tracking; and means for waveshaping said error signal into a wave shaped error signal; and wherein said producing means uses said wave shaped error signal to produce said velocity signal.

Claim 9

An apparatus as in claim 7, wherein said producing means includes frequency to voltage converting means for converting a frequency of said wave shaped error signal into said velocity signal.

Claim 10

A record disc reproducing apparatus for use in reproducing data stored thereon, comprising: a pick-up device for reading data from a disc and which is movable in a radial direction with respect to said disc; means for driving said pick-up device with respect to said disc, said driving means producing an output signal for driving said pick up device, said output signal including a phase stabilization for a reproducing mode; means for detecting a moving velocity of said pick-up device and producing a velocity signal corresponding to the moving velocity; a source for supplying a reference voltage signal; means for comparing said velocity signal with said reference voltage signal and generating a kick signal in response to the comparison and supplying said pick-up device driving means with said kick signal so that said detected velocity signal assumes a predetermined fixed relation with respect to said reference voltage signal; and a feedback path for subtracting an equalizing component from said kick signal to substantially remove said phase stabilization when said record disc reproducing apparatus is in a search mode.

Claim 11

A record disc reproducing apparatus for use in reproducing data stored thereon, comprising: a pick-up device for reading data from a disc and which is movable in a radial direction with respect to said disc; means for driving said pick-up device with respect to said disc, said driving means producing an output signal for driving said pick up device, said output signal including a phase stabilization for a reproducing mode; means for detecting a moving velocity of said pick-up device and producing a velocity signal corresponding to the moving velocity; a source for supplying a reference voltage signal; means for comparing said velocity signal with said reference voltage signal and generating a kick signal in response to the comparison and supplying said pick-up device driving means with said kick signal so that said detected velocity signal assumes a predetermined fixed relation with respect to said reference voltage signal; and a feedback path for subtracting an equalizing component from said kick signal to substantially remove said phase stabilization when said record disc reproducing apparatus is in a search mode.

Claim 12

A record disc reproducing apparatus according to claim 9, wherein said velocity detecting means includes means for generating a signal corresponding to the moving velocity of said pick-up device.

Claim 13

A record disc reproducing apparatus according to claim 10, wherein said generating means includes frequency generator means for generating a frequency signal corresponding to the velocity of said pick-up device.

Claim 14

A record disc reproducing apparatus according to claim 9, wherein said velocity detecting means includes means for sensing a pickedup signal read by said pick-up device.

Claim 15

A record disc reproducing apparatus according to claim 12, wherein said sensing means includes means for monitoring a ripple component of said picked-up signal.

Claim 16

A record disc reproducing apparatus according to claim 12, wherein said sensing means is responsive to a tracking error signal read by said pick-up device.

Claim 17

A record disc reproducing apparatus according to claim 12, wherein said sensing means is responsive to a ripple component and a tracking error signal read by said pick-up device.

Claim 18

A record disc reproducing apparatus for use in reproducing data stored thereon, comprising: a pick-up device for reading data from a disc and which is movable in a radial direction with respect to said disc; means for driving said pick-up device radially with respect to said disc; means for detecting a moving velocity of said pick-up device and producing a velocity signal corresponding to the moving velocity; a source for supplying a reference voltage signal; means for generating a kick signal and supplying said pick-up device driving means with said kick signal, said kick signal generating means comparing said velocity signal with said reference voltage signal and controlling said kick signal in response to the comparison so that said detected velocity signal assumes a predetermined fixed relation with respect to said reference voltage signal; a feedback path for subtracting an equalizing output of said pick up device driving means from said kick signal when said record disc reproducing apparatus is in a search mode; switch means for selectively connecting one of a picked-up signal read by said pick-up device and said kick signal to said pick-up device driving means; means for determining a distance that said pickup device should jump when said search mode is requested for accessing a desired track location; means for detecting when said pick-up device reaches the desired track location; and means for commanding said switch means to select a connection to said kick signal when said search mode is requested and to select a connection to said pick-up signal when said desired track location has been detected.

Claim 19

A record disc reproducing apparatus for use in reproducing data stored thereon, comprising: a pick-up device for reading data from a disc and which is movable in a radial direction with respect to said disc; means for driving said pick-up device radially with respect to said disc; means for detecting a moving velocity of said pick-up device and producing a velocity signal corresponding to the moving velocity; a source for supplying a reference voltage signal; means for generating a kick signal and supplying said pick-up device driving means with said kick signal, said kick signal generating means comparing said velocity signal with said reference voltage signal and controlling said kick signal in response to the comparison so that said detected velocity signal assumes a predetermined fixed relation with respect to said reference voltage signal; a feedback path for subtracting an equalizing output of said pick up device driving means from said kick signal when said record disc reproducing apparatus is in a search mode; switch means for selectively connecting one of a picked-up signal read by said pick-up device and said kick signal to said pick-up device driving means; means for determining a distance that said pickup device should jump when said search mode is requested for accessing a desired track location; means for detecting when said pick-up device reaches the desired track location; and means for commanding said switch means to select a connection to said kick signal when said search mode is requested and to select a connection to said pick-up signal when said desired track location has been detected.

Claim 20

A record disc reproducing apparatus according to claim 16, wherein said reference voltage signal source selectively provides a first reference voltage signal and a second reference voltage signal higher than said first reference voltage signal and said apparatus further comprises means of controlling said reference voltage signal source so that it provides said second reference voltage signal to said kick signal generating means until the pick-up device has jumped the distance determined by said distance determining means and then provides said first refernece voltage signal to said kick signal generating means until the desired track location is reached by said pick-up device.