JPH0221404A - Reproducing device - Google Patents

Abstract

PURPOSE:To perform demodulation and reproduction with superior S/Ns by providing an equalizer circuit for video signals with different frequency bands and an equalizer circuit for audio, and using the equalizer circuit corresponding to a signal based on whether it is a High-Band video signal, a Low-Band video signal, or an audio signal. CONSTITUTION:H/L discrimination is performed by comparing the level of the carrier frequency band of Low-Band with that of High-Band by a comparator 54. A system controller 20 switches the equalizer circuit to an H.B-EQ7, an L.-EQ8, or an A-EQ9 by a change-over switch 13 corresponding to whether the signal is the High-Band video signal, the Low-Band video signal, or the audio signal. Thus, since the optimum compensation of the output of a reproducing head can be performed by providing plural equalizer circuits for each signal and selecting the equalizer circuit corresponding to the signal to be reproduced, it is possible to improve the S/N by the reduction of reversal and the improvement of a C/N.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reproducing apparatus for reproducing a recording medium on which high-band video signals and audio signals, such as still videos, are recorded.

[Prior Art] Generally, when reproducing a magnetically recorded recording medium, the high-frequency output of the reproducing head decreases due to limitations of the electromagnetic conversion system. Therefore, in the conventional playback system of a still video (SV) signal recording/playback device, the output of the playback head is corrected by increasing the high frequency range using an equalizer.

FIG. 3 is a block diagram showing a conventional playback device IIIW. 101 is a magnetic disk, 102 is a spindle motor, 103 is a magnetic head for reproducing signals, 104
is a magnetic sensor that reads the reference position of the magnetic disk 101;
105 is a preamplifier that amplifies the reproduction signal, 106 is a timing signal generation circuit that generates a timing signal for the rotation of the magnetic disk 101, and 107 is an equalizer circuit (hereinafter referred to as E).
10B is an unrecorded discrimination circuit, 109 is a video discrimination circuit, 110 is an FM demodulation circuit, 11 is a de-emphasis circuit for video signals, 112 is a de-emphasis circuit for audio signals, 113 is an audio discrimination circuit, 114 115 is an image reproduction circuit; 115 is an audio reproduction circuit; 11
6 is a system controller.

In the reproducing apparatus shown in FIG. 3, a magnetic head 103 is placed from above a magnetic disk 101 rotating on a spindle motor 102.
The signal reproduced by is amplified by the preamplifier 105 and then EQ107 and unrecorded determination:? tiaxos,
The signal is supplied to a video discrimination circuit 109. The EQ107 boosts the high frequency components to compensate for the decrease in the high frequency components due to the electromagnetic conversion system. Therefore, if the characteristics of this equalizer circuit do not match the reproduced signal, an inversion phenomenon or C/N (carrier/noise) deterioration will occur. The unrecorded determination circuit 10B determines whether the reproduction signal is noise, that is, unrecorded, or a signal, that is, recorded, based on the average level of the reproduced signal, for example.
The system controller 116 is notified. For example, the video discrimination circuit 109 determines that the playback signal is a video signal if there are horizontal and vertical synchronization signals, and the system controller 11
Tell 6. Therefore, in the system controller 116, the unrecorded determination circuit 108 determines that the signal is not unrecorded, and the video determination circuit 109 determines that the signal that is not a video signal is an audio signal. And EQ circuit 10
The signal compensated for high frequencies by 7 is demodulated by an FM demodulation circuit 110, and if it is a video signal, it passes through a de-emphasis circuit 111 and an image is reproduced by an image reproduction circuit 114. Also, the unrecorded determination circuit 108 determines that it has been recorded,
The video signal determined by the video discrimination circuit 109 is passed through the de-emphasis circuit 112 to the audio reproduction circuit 1.
15 and the audio will be played. Furthermore, the signal that has passed through the de-emphasis circuit 112 is judged by an audio discrimination circuit 113 as to whether it is an audio signal. The audio determination circuit 113 determines whether the signal is an audio signal, for example, based on whether or not there is a flag or control code that is unique to the audio signal. This is to deal with cases where the unrecorded discrimination circuit 108 erroneously determines that the data has been recorded because the noise level is high when the data has not been recorded or is insufficiently erased.

With the system configuration as described above, the Sv image signal and audio signal are reproduced.

[Problem to be solved by the invention] In conventional still video, for example, there are video signals and audio signals as signals for recording and reproducing. Old gh-Ban trying to improve image quality
d video signals are being considered. These audio signals and low-band video signals.

Since the 11igh-Band video signals have different recording formats, the gain and frequency characteristics of the playback head output are different. However, in the conventional example described above, only one equalizer circuit compensates for the output of the playback head, but it is not possible to perform optimal compensation for each signal, which may result in an inversion phenomenon or deterioration of C/N and S/N. Ta.

The present invention has been made to solve this problem, and it is an object of the present invention to provide a reproducing apparatus that can compensate for the output of a reproducing head by providing an equalizer circuit adapted to each signal band.

[Means for Solving the Problems] In order to achieve the above object, the playback device of the present invention includes an equalizer circuit for two mutually different video signals in the frequency a band and an equalizer circuit for the audio signal. and means for using respective equalizer circuits according to the reproduced signals.

[Function] - According to the configuration described in item h, it has a plurality of equalizer circuits for each signal, and by selecting the equalizer circuit according to the signal to be reproduced, the optimum reproduction head output can be compensated, so that the inversion phenomenon can be avoided. The S/N can be improved by reducing the C/N and improving the C/N.

[Embodiment] Fig. 1 is a system block diagram showing a schematic configuration of the main parts of the reproducing apparatus of the present invention, in which 1 is a magnetic disk, 2 is a spindle motor, 3 is a magnetic head for reproducing signals, and 4 is a magnetic head. A magnetic sensor reads the reference position of the disk l, 5 is a preamplifier that amplifies the reproduction signal, 6 is a timing signal generation circuit that generates a timing signal for the rotation of the magnetic disk 1, and 7 is an equalizer circuit for 11ight-Band video signals (hereinafter referred to as II-II-EQ), 8 is Low-
Band video signal equalizer circuit (hereinafter referred to as ),・B
-EQ), 9 is an audio signal equalizer circuit (hereinafter referred to as A-EQ), IO is an unrecorded determination circuit, 1
1 is a video discrimination circuit that discriminates whether the signal is a video signal;
2 is an H/L discrimination circuit that measures whether it is an old GH-Band signal or a Low-Band signal, 13 is a changeover switch that switches the equalizer circuit according to instructions from the system controller 20, 14 is an FM demodulation circuit that demodulates the signal, and 15 is a video A de-emphasis circuit for signals, 16 a de-emphasis circuit for audio signals, 17 an audio discrimination circuit for determining whether the signal is an audio signal, 18 an image reproducing circuit for reproducing an image from a video signal, and 19 reproducing sound from an audio signal. The audio reproduction circuit 20 is a system controller. II-B-EQ7, L-B-EQ
8. Each equalizer circuit of A-EQ9 and H/L discrimination circuit 12. The operations other than the changeover switch 13 are similar to those of the conventional example shown in FIG.

Now, the signal reproduced by the magnetic head 3 from the magnetic disk 1 which is being rotated by the spindle motor 2 is amplified by the preamplifier 5 and then sent to the H-B-EQ7 and L-B.
-EQ8, A-EQ9, unrecorded determination circuit 10. Video discrimination circuit 11. ) (/L discrimination circuit 12. Here, the configuration of the H/L discrimination circuit 12 is shown in FIG.

In FIG. 2, 50 is a bandpass filter that extracts the Low-Band carrier frequency band, and 51 is the old gh-Ban.
bandpass filter for extracting the frequency band of carrier d, 52
．． 53 is a detection circuit, and 54 is a comparator. Low-Ba
H
/L determination is performed.

At this point, the system controller 20 determines that the unrecorded discrimination circuit 10 is not unrecorded, and the video discrimination circuit 11
If it is determined that the signal is not a video signal, it is determined that the signal is an audio signal.

The system controller 20 recognizes that the signal is the old gh-Ban.
d video signal, Low-Band video signal, or audio signal, each equalizer circuit is set to 1l-B.
-EQ7, LB-EQ8, and A-EQ9 using the changeover switch 13.

The FM demodulation circuit 14 demodulates the image, the video signal de-emphasis 159 image reproduction circuit 18 reproduces the image, and the audio signal de-emphasis circuit 16''
The operation of reproducing audio in the audio reproducing circuit 19 is the same as in the conventional example.

High-Band video signal, Low-Band
video signal.

The audio signal is the carrier frequency during FM modulation.

Since the deviations are different, the frequency bands are different. In particular, the old GH-Band video signal, which has improved image quality on a daily basis, has a higher recording frequency than audio signals and Low-Band video signals, so the conventional equalizer circuit (E
Q), high frequency components are not compensated and good demodulation cannot be performed. Therefore, by providing equalizer circuits corresponding to each as in the present invention, good demodulation can be achieved.

[Effects of the Invention] As explained above, the present invention has an equalizer circuit for video signals having different frequency bands, and an equalizer circuit for audio, and has an equalizer circuit for audio signals, whether the signal is an old GH-Band video signal or a Low-Band video signal. By using equalizer circuits depending on the audio signal, demodulation and reproduction with a good S/N ratio can be performed without causing inversion.

[Brief explanation of drawings]

No. 11''S7I is a system block diagram showing the schematic configuration of the main parts of the playback device of the present invention, and FIG. 2 is the H/L of FIG. 1.
A system block diagram showing an example of a discrimination circuit, and FIG. 3 is a block diagram showing an outline of a conventional playback device. In the figure. Magnetic disk spindle motor Magnetic head Magnetic sensor Preamplifier Timing signal generation circuit Old gh-Band video signal equalizer Low-B
Equalizer for and video signal Equalizer for audio signal Unrecorded discrimination circuit Video discrimination circuit H/L discrimination circuit Equalizer switching switch FM demodulator De-emphasis circuit for video De-emphasis circuit for audio De-emphasis circuit Audio discrimination circuit Image reproduction circuit Audio reproduction circuit System controller

Claims (1)

[Claims] A playback device comprising: an equalizer circuit for two video signals having different frequency bands; and an equalizer circuit for an audio signal; and means for using the equalizer circuits according to the playback signals. .