Disc playback apparatus for reproducing sequentially recorded digital data

Claim 2

A disc playback apparatus for reproducing data from a disc having recorded sequentially thereon digital data including at least image data or computer data as a main data, which comprises: a single motor operable to rotate the disc; a pick-up assembly operable to read the data from the disc and to output an electrical signal corresponding thereto; a wave shaping means for shaping the electrical signal output from the pick-up assembly into a pulse signal and for outputting the pulse signal; a clock extracting means for receiving the pulse signal from the wave shaping means and for extracting a playback clock signal from the pulse signal; a reference clock generating means for outputting a reference clock signal and a reference clock signal control means for continuously varying a frequency of the reference clock signal; a switching means adapted to be externally switched on and off; wherein said reference clock control means controls the reference clock generating means so that the frequency of the reference clock signal is increased when the switching means is switched on, but is decreased when the switching means is switched off; a rotation servo means for controlling the spindle motor so that the frequency of the playback clock signal outputted from the clock extracting means is consistent with the frequency of the reference clock signal outputted from the reference clock generating means; a digital signal processing means for receiving the pulse signal outputted from the wave shaping means, the playback clock signal outputted from the clock extracting means and the reference clock signal outputted from the reference clock generating means and for latching data from the pulse signal on the basis of the playback clock signal, and for subjecting the latched data to a first process and to output the data after being processed by the first process, according to the reference clock signal; and a processing and outputting means for receiving data outputted from the digital signal processing means and for subjecting the data attributes to a second process and then to output the data after being processed by the second process.

Claim 3

The disc playback apparatus as claimed in claim 1, wherein the reference clock generating means comprises a quartz oscillator, a digital-to-analog converter and a voltage-to-frequency converter, and wherein said reference clock control means selects a clock signal generated by the quartz oscillator as the reference clock signal during a normal playback, but selects a clock signal generated by the voltage-to-frequency converter as the reference clock signal during a varied speed playback.

Claim 4

A disc playback apparatus for reproducing data from a disc having recorded sequentially thereon digital data including at least image data or computer data as a main data, which comprises: a spindle motor operable to rotate the disc; a pick-up assembly operable to read the data from the disc and to output an electrical signal corresponding thereto a wave shaping means for shaping the electrical signal output from the pick-up assembly into a pulse signal and for outputting the pulse signal; a clock extracting means for receiving the pulse signal outputted from the wave shaping means and for extracting a playback clock signal from the pulse signal; a reference clock generating means for outputting a reference clock signal and a reference clock signal control means for continuously varying a frequency of the reference clock signal; a speed input means for externally inputting speed data in the form of a numerical value and then outputting such speed data; wherein said reference clock control means controls the reference clock generating means so as to increase the frequency of the reference clock signal if a required playback speed is faster than a current playback speed and to decrease the frequency of the reference clock signal if the required playback speed is lower than the current playback speed, in accordance with the speed data outputted from the speed input means; a rotation servo means for controlling the spindle motor so that the frequency of the playback clock signal outputted from the clock extracting means is consistent with the frequency of the reference clock signal outputted from the reference clock generating means; a digital signal processing means for receiving the pulse signal outputted from the wave shaping means, the playback clock signal outputted from the clock extracting means and the reference clock signal outputted from the reference clock generating means and for latching data from the pulse signal on the basis of the playback clock signal, and for subjecting the latched data to a first process and to output the data after being processed by the first process, according to the reference clock signal; and a processing and outputting means for receiving data outputted from the digital signal processing means and for subjecting the data attributes to a second process and then to output the data after being processed by the second process.

Claim 5

A disc playback apparatus for reproducing data from a disc having recorded sequentially thereon digital data including at least image data or computer data as a main data, which comprises: a spindle motor operable to rotate the disc; a pick-up assembly operable to read the data from the disc and to output an electrical signal corresponding thereto a wave shaping means for shaping the electrical signal output from the pick-up assembly into a pulse signal and for outputting the pulse signal; a clock extracting means for receiving the pulse signal outputted from the wave shaping means and for extracting a playback clock signal from the pulse signal; a reference clock generating means for outputting a reference clock signal and a reference clock signal control means for continuously varying a frequency of the reference clock signal; a speed input means for externally inputting speed data in the form of a numerical value and then outputting such speed data; wherein said reference clock control means controls the reference clock generating means so as to increase the frequency of the reference clock signal if a required playback speed is faster than a current playback speed and to decrease the frequency of the reference clock signal if the required playback speed is lower than the current playback speed, in accordance with the speed data outputted from the speed input means; a rotation servo means for controlling the spindle motor so that the frequency of the playback clock signal outputted from the clock extracting means is consistent with the frequency of the reference clock signal outputted from the reference clock generating means; a digital signal processing means for receiving the pulse signal outputted from the wave shaping means, the playback clock signal outputted from the clock extracting means and the reference clock signal outputted from the reference clock generating means and for latching data from the pulse signal on the basis of the playback clock signal, and for subjecting the latched data to a first process and to output the data after being processed by the first process, according to the reference clock signal; and a processing and outputting means for receiving data outputted from the digital signal processing means and for subjecting the data attributes to a second process and then to output the data after being processed by the second process.

Claim 6

The disc playback apparatus as claimed in claim 3, wherein the reference clock generating means comprises a quartz oscillator, a digital-to-analog converter and a voltage-to-frequency converter, and wherein said reference clock control means selects a clock signal generated by the quartz oscillator as the reference clock signal during a normal playback, but selects a clock signal generated by the voltage-to-frequency converter as the reference clock signal during a varied speed playback.

Claim 7

A disc playback apparatus for reproducing data from a disc having recorded sequentially thereon digital data including at least image data or computer data as a main data, which comprises: a spindle motor operable to rotate the disc; a pick-up assembly operable to read the data from the disc and to output an electrical signal corresponding thereto; a wave shaping means for shaping the electrical signal output from the pick-up assembly into a pulse signal and for outputting the pulse signal; a clock extracting means for receiving the pulse signal outputted from the wave shaping means and for extracting a playback clock signal from the pulse signal; a reference clock generating means for outputting a reference clock signal and a reference clock signal control means for continuously varying a frequency of the reference clock signal; a speed input means for externally inputting speed data in the form of numerical value then outputting such speed data; wherein said reference clock control means controls the reference clock generating means so as to increase the frequency of the reference clock signal if a required playback speed is faster than a current playback speed and to decrease the frequency of the reference clock signal if the required playback speed is lower than the current playback speed, in accordance with speed data outputted from the speed input means and for also monitoring the absolute value of a difference between the respective frequencies of the reference and playback clock signals so as to thereby prevent the absolute value from exceeding a predetermined value; a rotation servo means for controlling the spindle motor so that the frequency of the playback clock signal outputted from the clock extracting means is consistent with the frequency of the reference clock signal outputted from the reference clock generating means; a digital signal processing means for receiving the pulse signal outputted from the wave shaping means, the playback clock signal outputted from the clock extracting means and the reference clock signal outputted from the reference clock generating means for latching data from the pulse signal on the basis of the playback clock signal, and for subjecting the latched data to a first process and to output the data after being processed by the first process, according to the reference clock signal; and a processing and outputting means for receiving data outputted from the digital signal processing means and for subjecting the data attributes to a second process and then to output the data after being processed by the second process.

Claim 8

A disc playback apparatus for reproducing data from a disc having recorded sequentially thereon digital data including at least image data or computer data as a main data, which comprises: a spindle motor operable to rotate the disc; a pick-up assembly operable to read the data from the disc and to output an electrical signal corresponding thereto; a wave shaping means for shaping the electrical signal output from the pick-up assembly into a pulse signal and for outputting the pulse signal; a clock extracting means for receiving the pulse signal outputted from the wave shaping means and for extracting a playback clock signal from the pulse signal; a reference clock generating means for outputting a reference clock signal and a reference clock signal control means for continuously varying a frequency of the reference clock signal; a speed input means for externally inputting speed data in the form of numerical value then outputting such speed data; wherein said reference clock control means controls the reference clock generating means so as to increase the frequency of the reference clock signal if a required playback speed is faster than a current playback speed and to decrease the frequency of the reference clock signal if the required playback speed is lower than the current playback speed, in accordance with speed data outputted from the speed input means and for also monitoring the absolute value of a difference between the respective frequencies of the reference and playback clock signals so as to thereby prevent the absolute value from exceeding a predetermined value; a rotation servo means for controlling the spindle motor so that the frequency of the playback clock signal outputted from the clock extracting means is consistent with the frequency of the reference clock signal outputted from the reference clock generating means; a digital signal processing means for receiving the pulse signal outputted from the wave shaping means, the playback clock signal outputted from the clock extracting means and the reference clock signal outputted from the reference clock generating means for latching data from the pulse signal on the basis of the playback clock signal, and for subjecting the latched data to a first process and to output the data after being processed by the first process, according to the reference clock signal; and a processing and outputting means for receiving data outputted from the digital signal processing means and for subjecting the data attributes to a second process and then to output the data after being processed by the second process.

Claim 9

The disc playback apparatus as claimed in claim 5, wherein the reference clock generating means comprises a quartz oscillator, a digital-to-analog converter and a voltage-to-frequency converter, and wherein said reference clock control means selects a clock signal generated by the quartz oscillator as the reference clock signal during a normal playback, but selects a clock signal generated by the voltage-to-frequency converter as the reference clock signal during a varied speed playback.