JP3041992B2 - Disc playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk reproducing apparatus capable of system conversion.

[0002]

2. Description of the Related Art In an electronic still camera, a still image television signal obtained by imaging with an image sensor is recorded on a magnetic disk. In this case, a luminance signal and two types of color difference signals are obtained from a camera signal processing circuit and supplied to a recording circuit. The luminance signal is FM-modulated, and the two types of color difference signals are converted into a line-sequential color difference signal. With a carrier frequency different from the carrier frequency in the case of
The signal is modulated, the FM luminance signal and the FM line-sequential color difference signal are multiplexed and supplied to a magnetic head, and one field is recorded on one track of a magnetic disk rotating at a field frequency (vertical frequency). At the time of reproduction, the reproduction signal from the magnetic head is frequency-separated to obtain an FM luminance signal and an FM line-sequential color difference signal, each of which is FM-demodulated to obtain a luminance signal and a line-sequential color difference signal. Performs dropout compensation and skew correction, and the line-sequential color difference signal is subjected to skew correction, dropout compensation and synchronization processing to obtain a simultaneous color difference signal.

In an electronic still camera, for example, a PAL system luminance signal and two types of color difference signals are obtained from a camera signal processing circuit and supplied to a recording circuit, and an FM luminance signal and an FM line obtained from the recording circuit are obtained. Sequentially supplying a multiplexed signal of color difference signals to a magnetic head, recording one field thereof on one track of a magnetic disk, and reproducing it to obtain, for example, a luminance signal and a simultaneous color difference signal of the NTSC system; Or, in order to perform the reverse, conventionally, a read signal reproduced from a magnetic disk by a magnetic head is used to calculate P
Obtain an AL (or NTSC) luminance signal and a simultaneous color difference signal, write them into the field memory,
The data is read out, and the way of controlling the writing and reading is changed according to the difference in the television system.

[0004]

However, the conversion method of the television system by the conventional disk reproducing apparatus requires a field memory having a large storage capacity.
There is a drawback that the disc reproducing apparatus becomes expensive. In view of the above, an object of the present invention is to propose a disk reproducing apparatus capable of performing conversion of a television system using a small-capacity memory.

[0005]

According to the present invention, there is provided a first image processing apparatus comprising: a vertical frequency of VF1 and the number of scanning lines per vertical cycle being N1.
A television signal of the second system is recorded on a disk 2 rotating at a rotation speed R1, and a television signal of the second system having a vertical frequency of VF2 and N2 scanning lines per vertical cycle is recorded from the disk 2. A disk reproducing apparatus for reproducing data, the disk 2 having a rotation speed R2 (= R1 · V
F2 / VF1).
9 and the reproduction signal from the disk 2 rotating at the rotation speed R2, when N1 / N2 is greater than 1, (n1 / n2)
(However, n1 and n2 are integers having no common divisor, and the time axis is extended by a factor of n1 / n2ＮN1 / N2), and n1 line signals are included in the reproduction signal extended by the time axis. For each (n1-n2) line signals, N
When 1 / N2 is smaller than 1, the time axis is compressed to (n1 / n2) and (n2-n1) for every n1 line signals.
Signal processing means 10 for adding the line signal of the book,
The signal processing means 10 outputs a television signal of the second system.

[0006]

According to the present invention, the rotary driving means 3, 4,
9, the disk 2 is rotated at a rotational speed R2 (= R1 · VF2).
/ VF1), and a reproduction signal from the disk 2 rotating at the rotation speed R2 is supplied to the signal processing means 10, whereby a television signal of the second system is output.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A PAL television signal is recorded on a disk, an NTSC television signal is obtained from the reproduced signal, and conversely, an NTSC television signal is recorded on a disk. From the reproduced signal, P
An embodiment in which the present invention is applied to a magnetic disk recording / reproducing apparatus which obtains an AL television signal will be described in detail.

[0008] A comparison between a television signal of the NTSC system and a television signal of the PAL system shows that the
The field frequency (vertical frequency) of the SC television signal is 60 Hz, the scanning line of one field (one vertical cycle) is 525/2 lines, and the field frequency (vertical frequency) of the PAL television signal is 50 Hz, one field. The number of scanning lines (1 vertical cycle) is 625/2.

Therefore, first, conversion of the field frequency (vertical frequency) of both television systems can be performed by changing the number of rotations of the magnetic disk during recording and during reproduction. However, in the NTSC and PAL television signals, one field (one vertical cycle)
Since the number of scanning lines is different, the system conversion cannot be achieved simply by changing the rotational speed of the magnetic disk between recording and reproduction in accordance with the field frequency (vertical frequency).

The number of scanning lines in one field (one vertical cycle) of the NTSC and PAL television signals is 525/2 and 625/2, respectively, and the ratio is approximately 5:
6. Therefore, when a PAL television signal is recorded on a magnetic disk and an NTSC television is obtained from the reproduced signal, the rotation speed of the magnetic disk is set to 50 Hz during recording and to 60 Hz during reproduction.
As shown in (1) and (2), it can be seen that the time axis of the reproduced signal is extended by a factor of 6/5 and one line signal F should be thinned out of the six line signals A to F. Conversely, when a NTAL television signal is recorded on a magnetic disk and a PAL television is obtained from the reproduced signal, the number of rotations of the magnetic disk is set to 60.
Hz and 50 Hz during reproduction. As shown in FIGS. 1 (3) and (4), the reproduction signal is compressed to 5/6 on the time axis, and
It can be seen that it is sufficient to add one line signal E to the line signals A to E.

Next, referring to FIG. 3, it is possible to obtain an NTSC (or PAL) television signal from a reproduction signal of a magnetic disk on which a PAL (or NTSC) television signal is recorded. An example of a possible magnetic disk reproducing apparatus will be described.

In the mechanical deck 1, reference numeral 2 denotes a magnetic disk, and reference numeral 3 denotes a motor for driving the disk 2 to rotate.
The motor 3 is driven to rotate by the output of the servo circuit 4. The recording signal of the disk 2 is reproduced by the magnetic head 5 and supplied to the head amplifier 6.

The FM television signal (F
The M luminance signal signal and the superimposed signal of the FM line-sequential color difference signal) are supplied to the FM demodulation circuit 7 where they are FM-demodulated, respectively.
A luminance signal and a line-sequential color difference signal are output, respectively. F
The luminance signal and the line-sequential color difference signal from the M demodulation circuit 7 are supplied to a synchronization processing circuit 8 and an NTSC / PAL system discrimination circuit 9. The synchronization processing circuit 8 includes a dropout compensation circuit and a skew correction circuit for a luminance signal, and a dropout compensation circuit, a skew correction circuit, and a synchronization circuit for a line-sequential color difference signal.

The NTSC / PAL system discrimination circuit 9 discriminates between the NTSC system and the PAL system based on the number of horizontal synchronization signals in the reproduced luminance signal based on one rotation of the magnetic disk 1. The discrimination output of the discrimination circuit 9 is supplied to the servo circuit 4 and reproduces a PAL television signal.
When the NTSC television signal is obtained, the rotation speed of the motor 3 is set to 60 Hz. When the NTSC television signal is reproduced and the PAL television signal is obtained, the rotation speed of the motor 3 is increased. The switching of the servo circuit 4 is controlled so that the frequency becomes 50 Hz.

The luminance signal and the two synchronized color difference signals from the synchronization processing circuit 8 are supplied to a time axis compression / expansion circuit 10. This time axis compression / expansion circuit 10 is shown in FIG.
This will be described with reference to FIG. This time axis compression / expansion circuit 10
Is composed of three circuits having the same configuration for the luminance signal and the two color difference signals. Therefore, a time axis compression / decompression circuit for the luminance signal will be described as an example. The luminance signal is
The data is supplied from an input terminal 13 to a 1H (one horizontal cycle) memory 14, written by a write clock signal WCK from a timing circuit 15, and read by a read clock signal RCK from the timing circuit 15. According to the NTSC / PAL system discrimination signal supplied to the input terminal 16, the luminance signal reproduced from the disc 2 is converted to the PAL signal.
In the case of the system, the frequency of the write clock signal WCK is set to 6/5 of the read clock signal RCK, the luminance signal is expanded to 6/5, and one line signal is generated for every six line signals. The moving contact a is output to the output terminal 22 through the changeover switch 17 in which the movable contact a is switched to the fixed contact b in accordance with the NTSC / PAL system determination signal supplied to the input terminal 18 after being thinned out. According to the NTSC / PAL system discrimination signal supplied to the input terminal 16, the television signal reproduced from the disc 2
In the case of the SC system, the frequency of the write clock signal WCK is set to 5/6 of the read clock signal RCK, the luminance signal is compressed to 5/6, and the input terminal 1
8, the movable contact a is supplied to the fixed contact c of the changeover switch 17 in which the movable contact a is switched to the fixed contact c, and the luminance signal of the fixed contact c of the changeover switch 17 is supplied to one side. The other is controlled to be switched by the switching signal from the input terminal 21 through the 1H delay unit 19, and the movable contact f is switched to the fixed contact d during the five line signals among the six line signals. , Movable contact f during one line signal
Switch 20 that switches to the fixed contact e side
And one line signal is added to the five line signals and output to the output terminal 22.

The output of the time axis compression / expansion circuit 10 is
Supplied to the encoder 11, NTSC or PAL
The signal is converted into a composite color television signal of three types, a three primary color signal, and the like, and output to the output terminal 12.

In the above embodiment, the case where the present invention is applied to a magnetic disk reproducing apparatus has been described. However, the present invention can also be applied to an optical disk reproducing apparatus and a magneto-optical disk reproducing apparatus.

[0018]

According to the present invention described above, the vertical frequency is VF1 and the number of scanning lines per vertical cycle is N1.
Is recorded on a disk that rotates at a rotation speed R1, and the vertical frequency is V
F2, a disk reproducing apparatus for reproducing a television signal of the second system having N2 scanning lines per vertical cycle, wherein the disk is rotated at a rotation speed R2 (= R1.VF2 //
VF1), a rotation driving unit for rotating the rotation speed R2,
The reproduction signal from the rotating disk is divided into N1 / N2
Is greater than 1 (n1 / n2) (where n1, n2
Is an integer having no common divisor, and n1 / n2 ≒ N
(1 / N2) times the time axis, and (n1-
n2) line signals are thinned out, and when N1 / N2 is smaller than 1, the time axis is compressed to (n1 / n2) and n1
Signal processing means for adding (n2-n1) line signals to each of the line signals, and a television signal of the second system is output from the signal processing means. The conversion of the television system can be performed using a memory and with a simple configuration and a simple operation, so that the cost of the disk reproducing apparatus is reduced. In addition, the disc reproducing apparatus of the present invention provides a normal reproduction of reproducing a first (or second) television signal from a disc on which a first (or second) television signal is recorded. Can also be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of time axis compression / expansion.

FIG. 2 is a block diagram showing a time axis compression / expansion circuit.

FIG. 3 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 2 Disk 3 Motor 4 Servo circuit 5 Magnetic head 7 FM demodulation circuit 8 Synchronization processing circuit 9 NTSC / PAL system discrimination circuit 10 Time axis compression / expansion circuit 11 Encoder 14 1H memory 15 Timing circuit 17 Switching switch 19 1H delay unit 20 Switching switch

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/85 H04N 7/01 H04N 9/79-9/898 H04N 11/20

Claims (1)

(57) [Claims] 1. A television signal of a first system having a vertical frequency of VF1 and N1 scanning lines per vertical cycle is recorded on a disk rotating at a rotation speed R1, and a vertical frequency of VF2 is output from the disk. A disk reproducing apparatus for reproducing a television signal of the second system having N2 scanning lines per vertical cycle, wherein the disk is rotated at a rotational speed of R2 (= R1 / VF2 / VF1). A driving means and a reproduction signal from the disk rotating at the rotation speed R2, wherein N1 / N2 is greater than 1 (n1 / n2) (where n1 and n2 are integers having no common divisor; In addition, the time axis is extended by (n1 / n2 ≒ N1 / N2) times, and among the reproduced signals that have been extended on the time axis,
(n1-n2) line signals are thinned out for every n1 line signals, and when N1 / N2 is smaller than 1, (n1 / n)
2) signal processing means for compressing the time axis and adding (n2−n1) line signals for each of n1 line signals, wherein the signal processing means outputs a television signal of the second system. A disc reproducing apparatus characterized in that the disc reproducing apparatus outputs the same.