JPH038172A - Information signal reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an information signal reproducing device for reproducing information signals from a disc-shaped recording medium in which information signals are recorded on concentric recording tracks. It is related to.

[Prior Art] Conventionally, an information signal such as a still image signal is subjected to FM modulation and recorded on a disk-shaped recording medium such as a magnetic disk, thereby forming concentric recording tracks on the magnetic disk. There are also electronic still video systems that reproduce recorded still image signals.

In the above-mentioned electronic still video, 50 recording tracks can be formed concentrically on the magnetic disk, and one recording track can record one field's worth of still image signals. It has become.

During reproduction, the magnetic disk is rotated at 60 revolutions per second, and the recorded still image signal is reproduced by tracing a magnetic head on each recording track.

In addition, during the above-mentioned reproduction, the relative speed between the magnetic head and the magnetic disk is slower in the inner recording track than the outer recording track on the magnetic disk, so the high frequency of the reproduced still image signal Since the level of the a component decreases, the compensation characteristics of the high frequency component for the still image signal reproduced from the inner recording track and the outer recording track on the magnetic disk are determined by a predetermined recording method on the magnetic disk. I am trying to switch between tracks.

[Problems to be Solved by the Invention] However, as in the above-mentioned conventional example, when a still image signal is reproduced from a recording track on the inner circumference side of the magnetic disk, with a predetermined recording track on the magnetic disk as a boundary, The question is whether it is possible to prevent deterioration of still image signals reproduced from recording tracks near where the compensation characteristics of the high frequency components switch by increasing the amount of compensation for the high frequency components. The still image signal reproduced from the recording track further inside the recording track near where the compensation characteristic of the high frequency component changes has poor image quality because the amount of compensation for the high frequency component is insufficient. - Therefore, it is an object of the present invention to provide an information signal reproducing device that can reproduce information signals recorded on a disk-shaped recording medium without deteriorating them.

[Means for Solving the Problems] The information signal reproducing device of the present invention is a device for reproducing information signals from a disk-shaped recording medium in which the information signals are recorded on concentric recording tracks, Reproducing means for tracing an arbitrary recording track on the disc-shaped recording medium, reproducing and outputting a signal recorded on the recording track, and compensating for high frequency components of the signal reproduced by the reproducing means. , a high frequency component compensating means for outputting, a frequency characteristic correcting means for correcting and outputting the frequency characteristic of the signal outputted from the high frequency a component compensating means, and the disk shape traced by the reproducing means. Control means for controlling the compensation characteristic of the high frequency component in the high frequency component correction means and the correction characteristic of the frequency characteristic in the frequency characteristic correction means according to the position of the recording track on the magnetic recording medium. This is what I did.

[Function] With the above-described configuration, the characteristics of high frequency component compensation and frequency characteristic correction applied to the signal reproduced from the recording track are adjusted according to the position of the recording track on the disk-shaped recording medium. By controlling the vehicle, it becomes possible to prevent the deterioration of the reproduced information signal.

[Example] Hereinafter, the present invention will be explained using examples of the present invention.

FIG. 1 is a diagram showing, as an embodiment of the present invention, a schematic configuration of a playback device in an electronic still video system to which the present invention is applied.

In FIG. 1, 1 is a magnetic disk as a recording medium;
2 is a motor for rotating the magnetic disk, 3 is a magnetic head, 4 is a head moving mechanism for moving the magnetic head 3 in the radial direction of the magnetic disk l, and 5 is the magnetic head 3.
6 is a high frequency component compensation circuit that compensates for the high frequency component of the reproduced signal amplified by the preamplifier 5; 7 is an output from the high frequency a component compensation circuit 6; 8 is an FM demodulation circuit for FM demodulating the reproduced signal and restoring the still image signal;
a low-pass filter that removes high-frequency components of the still image signal output from the demodulation circuit 7; 9 a de-emphasis circuit that performs de-emphasis processing on the still image signal output from the low-pass filter 8; 10 a system controller; A switching control circuit 11 switches the characteristics of the high frequency component compensation circuit 6 and the low-pass filter 8 according to instructions from the system controller 10.

In FIG. 1, during playback, the magnetic disk l is moved by the motor 2.
The magnetic head 3 is moved by a head moving mechanism 4 so as to trace an arbitrary recording track on the magnetic disk 1, and the magnetic head is rotated at a rotational speed of 60 revolutions per second. The recorded signal is reproduced and supplied to the preamplifier 5. Incidentally, by operating an operation section (not shown) in the system controller 10, a track to be reproduced among the recording tracks on the magnetic disk 1 is specified, and the system controller 10 selects the track specified by the operation section. A track position to which the magnetic head 3 is to be moved is designated to the head moving mechanism 4 so that the magnetic head 3 can trace it.

As described above, the magnetic head 3 is moved onto the recording track specified by the operation section, and the signal reproduced from the recording track by the magnetic head 3 is amplified by the preamplifier 5 and then sent to the high frequency component compensation circuit 6. supplied to

The high frequency component compensating circuit 6 compensates for the high frequency component that is lowered during reproduction with respect to the reproduced signal supplied from the preamplifier 5, and its compensation characteristics are shown in FIG.

As shown in FIG. 2, the high frequency component compensation circuit 6 has two types of compensation characteristics indicated by a and b in the figure. Based on
Compensates for high frequency components of the supplied reproduced signal.

Note that switching of the compensation characteristics of the high frequency component compensation circuit 6 is controlled by a switching control circuit 11. That is, the switching control circuit 11 is supplied with a signal instructing the position of the playback track, which is supplied from the system controller 10 to the head moving mechanism 4, and the system controller l
It is determined whether the instruction signal supplied from O indicates an inner recording track or an outer recording track of a predetermined recording track on the magnetic disk l, and the recording on the outer circumference is performed. When the track is designated, the compensation characteristic of the high frequency component compensation circuit 6 is set to the characteristic shown in a of FIG. 2, and when the inner recording track is designated, the compensation characteristic is set to the second one. The switching control circuit 11 outputs a compensation characteristic control signal to the high frequency component compensation circuit 6 so as to obtain the characteristic shown in b in the figure.

Then, the high frequency component compensation circuit 6, whose compensation characteristic is set by the compensation characteristic control signal outputted from the 'lJI# circuit 11, changes the high frequency component of the reproduced signal supplied from the preamplifier 5 as described above. After being compensated based on the set compensation characteristics, the signal is supplied to the FM demodulation circuit 7.

The FM demodulation circuit 7 restores the still image signal by FM demodulating the reproduced signal whose high frequency components have been compensated in the high frequency component compensation circuit 6, and the restored still image signal is supplied to the low pass filter 8. .

The low-pass filter 8 removes unnecessary high frequency components from the still image signal supplied from the FM demodulation circuit 7, and the characteristics of the low-pass filter are shown in FIG.

As shown in FIG. 3, the low-pass filter 8 has two types of low-pass characteristics indicated by c and d in the figure. Removes unnecessary high frequency components from still image signals.

Note that switching of the low-pass characteristic of the low-pass filter 8 is controlled by a switching control circuit 11. That is, as described above, the switching control circuit 11 includes the system controller 1.
A signal instructing the position of the reproduction track is supplied from the head moving mechanism 4 from the head moving mechanism 4, and an instruction signal supplied from the system controller 10 is supplied to the head moving mechanism 4 from the magnetic disk 1.
It is determined whether the recording track on the inner circumference side or the outer circumference side is specified for the above specified recording track, and if the recording track on the outer circumference side is specified, the low-pass filter is applied. The switching control circuit 11 sets the low-pass characteristic of No. 8 to the characteristic shown by C in FIG. 3, and sets the low-pass characteristic to the characteristic shown by d in FIG. from low pass filter 8
Outputs a low-pass characteristic control signal to.

The low-pass filter 8, whose low-pass characteristic is set by the low-pass characteristic control signal output from the switching control circuit 11 as described above, removes unnecessary high frequency components of the still image signal supplied from the FM demodulation circuit 7. After removing the signal based on the low-pass characteristics obtained, the signal is supplied to the de-emphasis circuit 9.

The de-emphasis circuit 9 uses the low-pass filter 8 to perform de-emphasis processing on the still image signal from which unnecessary high-frequency components have been removed, which has characteristics opposite to those of the emphasis processing performed during recording. From there, the still image signal recorded on the recording track on the magnetic disk l is restored and output to a monitor device (not shown) or the like.

As described above, in this embodiment, the high frequency component compensation applied before FMig is applied to the signal reproduced from the recording track on the inner side of the predetermined recording track on the magnetic disk l. Increase the compensation of high frequency components applied to the signal reproduced from the recording track, and
By comparing the removal of unnecessary high frequency components applied after M demodulation to the outer circumferential side, and performing 41 so that even lower frequency components on the inner circumferential side are removed, the inner circumferential side on the magnetic disk 1 is removed. This makes it possible to suppress deterioration of the still image signal reproduced from the recording track and improve the S/N ratio.

By the way, as mentioned above, in this embodiment, during reproduction, the characteristics of the low-pass filter that passes through after FM demodulation are switched according to the track position on the magnetic disk l.
However, the present invention is not limited to this, and the linear de-emphasis characteristic in the de-emphasis circuit after the low-pass filter may be switched.

FIG. 4 is a diagram showing the linear de-emphasis characteristics of the de-emphasis circuit in the above case, and when the track to be reproduced is on the outer circumferential side of the predetermined recording track on the magnetic disk l, the characteristic is shown as e in the figure. Based on
The de-emphasis circuit 9 is controlled by the switching control circuit 11 so that de-emphasis processing is performed based on the characteristics shown in
By configuring the linear emphasis characteristic to be switched between the two, it is possible to obtain the same effect as in the above-mentioned embodiment.

In addition, in this embodiment, an information signal reproducing apparatus for reproducing a still image signal from a magnetic disk on which the still image signal is recorded as an information signal has been described, but the present invention is not limited to this. It may be an apparatus that reproduces audio signals from a recording medium on which the audio signals are recorded, and the recording and reproducing method is not limited to magnetic recording and reproducing.

[Effects of the Invention] As explained above, according to the present invention, it is possible to provide an information signal reproducing device that can reproduce information signals recorded on a disk-shaped recording medium without deteriorating them. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing, as an embodiment of the present invention, a schematic configuration of a playback device in an electronic still video system to which the present invention is applied. FIG. 2 is a diagram showing the compensation characteristics of the high frequency component compensation circuit 6 of FIG. 1. FIG. 3 is a diagram showing the low-pass characteristics of the low-pass filter 8 of FIG. 1. FIG. 4 is a diagram showing linear de-emphasis characteristics in the de-emphasis circuit 9 of FIG. 1. 1... Magnetic disk 3... Magnetic head 4... Head moving mechanism 1 6... High frequency component compensation circuit 7... FM demodulation circuit 8... Low pass filter 9... De-emphasis circuit 0...System controller...Switching control circuit

Claims (1)

[Scope of Claims] A device for reproducing information signals from a disk-shaped recording medium in which information signals are recorded on recording tracks formed in concentric circles, the device comprising: an arbitrary recording track on the disk-shaped recording medium; a reproduction means for tracing, reproducing and outputting the signal recorded on the recording track; and a high frequency component compensating means for compensating and outputting the high frequency component of the signal reproduced by the reproduction means; frequency characteristic correction means for correcting and outputting the frequency characteristics of the signal output from the high frequency component compensation means; An information signal reproducing device comprising: a compensation characteristic of the high frequency component in the high frequency component correction means; and a control means for controlling the correction characteristic of the frequency characteristic in the frequency characteristic correction means.