JPH0212667A - Reproducing device - Google Patents

Abstract

PURPOSE:To attain excellent and stable reproduction by suppressing the disturbance of an output caused in the case of switching the characteristic of a processing means. CONSTITUTION:In the case of feeding a track, every time a track accessed by a head 3 is changed, the recording state of the track accessed by the head 3 is discriminated and the demodulation characteristic of a demodulator 8 is changed in response thereto. When the track accessed by the head 3 is changed in a shorter time than the reply time when the characteristic of the demodulator 8 is revised, since the characteristic of the demodulator 8 is not changed and the disturbance of a picture reproduced on a monitor 16 is prevented. Thus, the disturbance in the output caused at changeover is prevented and the picture is reproduced without disturbing the picture.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a playback device.

[Conventional technology]

As an example of such a reproducing apparatus, an image reproducing apparatus capable of reproducing video signals of a plurality of recording frequency bands is, for example, VT.
A device such as R is known, and in this device, when reproducing a video signal, it is known that the recording frequency band is determined, and the image is reproduced by performing processing in accordance with the recording mode. Conventionally, this determination of the recording mode has been performed every time the recording area of the medium changes.

[Problem that the invention is trying to solve]

However, in the above-mentioned device, each time the recording area being played back is changed, the frequency band of the image signal recorded in the recording area is determined, and the characteristics of the demodulator are changed in order to match the characteristics of the demodulator to the carrier frequency. When the output is changed, an unstable output state occurs, and the image on the monitor that reproduces the image signal as a visible image is disturbed. One reason for this is that it promotes malfunction of the monitor's zinc severance circuit.

If the speed of the above-mentioned change is increased, the period in which the image is disturbed becomes shorter, and the disturbance of the image on the monitor becomes more noticeable, which is a particularly serious problem.

The present invention aims to solve this problem.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a means for reproducing information recorded in different bands in each area of a medium, a process for processing and outputting a reproduced signal of the means with characteristics according to the band,
and means for suppressing disturbances in output that occur when switching the characteristics of the processing means.

[For production]

In the above configuration, the suppressing means prevents disturbances in the output that occur when switching the characteristics of the processing means.

〔Example〕

In the embodiment of the present invention described below, a still video is shown in which concentric tracks are formed on a magnetic disk called a video floppy and one screen of video is recorded on each track. Of course, the recording device may be a recording device that records on an optical disk, a tape-like medium, or a solid-state memory, or a device that records information other than video signals.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In this embodiment, in order to improve the horizontal resolution of images recorded on a recording medium, high band H recording is used to increase the carrier frequency when recording images, and 6 MHz to 7 MHz, which is specified by the still video format, is used. An apparatus for reproducing a disc in which image signals recorded by low band L recording using a carrier frequency of 5 MHz are mixed is disclosed.

The frequency bands of such high band H recording and low band H recording are shown in FIG.

Hereinafter, the present invention will be explained using the drawings. FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, 1 is a magnetic sheet, which is rotated at a constant speed by a spindle motor 2. In FIG. 3 is a magnetic head, which is accessed to a desired track position by a head feeding mechanism 4 controlled by a controller 12; 5
is a motor control circuit that controls the spindle motor 2. On the other hand, to explain the flow of the image signal, 6 is a preamplifier, which amplifies the image signal detected by the magnetic head 3. Here, the image signal is branched into a circuit for carrier detection and a circuit for original image reproduction processing. 7 is an equalizer, and 8 is a demosulator. In this embodiment, the reproduced carrier of the demosimulator 8 is switched by the controller 12 for high-band demodulation and low-band demodulation. The image signal is demodulated by demodulator 8 and outputted as an image reproduction signal by 15 output buffers 15.

Here, reference numeral 14 denotes a mute circuit, which normally transmits the signal from the demosimulator 7 to the output buffer 15 through it.

On the other hand, in the carrier detection configuration, the output of the preamplifier 6 is
After amplifying it with the amplifier, it passes through B, P, and F of 10.

In this embodiment, a plurality of B, P, and F are prepared, and the carrier frequency is determined by comparing the magnitudes of the outputs of B, P, and F, which have different passbands. Assuming that the center frequencies of these respective passbands are 6, 6 MHz and 9 MHz as shown in C and C2 of Fig. 3, the carrier of the image signal at that point has a high frequency near 9 MHz. , when reproducing image signals recorded in the so-called high band H, the 9 MHz B, P, and F outputs are better than the 6
, 6 MHz outputs of B, P, and F become larger signals.

Reference numeral 11 denotes a carrier frequency discrimination circuit, which compares the outputs of each B, P, and F, and informs the controller 12 whether the image signal being reproduced is high band H or recorded in low band. .

The microcomputer 12 stores the carrier frequency for each track in a memory 17. When the track is accessed again, the output of the demodulator 8 is muted by the mute circuit 14 for a certain period of time using the timer 13. Reference numeral 16 denotes a monitor for reproducing the signal of the output buffer 15, which is connected as an external device to the apparatus of this embodiment.

Reference numeral 17 is the memory, which determines the presence or absence of recording on each track and the result of determining whether the signal recorded on each track is a video signal or another signal, and if it is a video signal, the high band It is stored for each track whether it was recorded in H or low band.

20 is a group of switches for outputting various instructions to the controller 12, including track feed speed change switches 20-1. ) It has a rack feed instruction UP/DOWN switch 20-2.

A circuit 24 performs envelope detection of the output of the amplifier 9, and the controller 12 determines whether or not the track being accessed by the head 3 is recorded by determining the output of the circuit 24. 26 detects a component in a predetermined frequency band of the output of the amplifier 9 and demodulates it, thereby outputting an ID signal recorded together with the image signal.

Note that when an audio signal is recorded, such ID signal is not output.

Therefore, when there is an output from the envelope detection circuit 24 and no output from the ID detection circuit 26, the controller 12 determines that the signal recorded on the track being accessed by the head 3 is a signal other than an image signal, that is, an audio signal. It can be determined that there is.

Reference numeral 28 denotes a character generator that causes the monitor 16 to display a character according to an instruction from the controller 12 via the output buffer 15.

Reference numeral 30 denotes a display LED that displays the status of the apparatus, and includes an LED that indicates that the image signal recorded on the track being accessed by the head 3 is an image recorded in a high band.

In this embodiment, images with different carrier frequencies may be recorded on the same magnetic sheet. When images with different carrier frequencies recorded on the magnetic sheet l are continuously reproduced, a voltage shift corresponding to the difference in carrier frequency occurs in the demodulated signal voltage of the demodulator 8, and a transient response of the voltage fluctuation causes a subsequent stage An unstable state occurs in the signal processing circuit, for example, the synchronization separation circuit of the monitor 16. This causes disturbances in the image reproduced on the monitor 16, causing discomfort to the user.

In this embodiment, in order to solve the above-mentioned problem, the recorded carrier frequency is discriminated by a carrier frequency discriminating circuit and stored in a memory via a controller 12 that controls track feeding. As mentioned above, if a general carrier frequency with low carrier frequency is low band and a higher carrier frequency is high band H, then the next track from low band L is high band H1 and the next track from high band H is continuous low band L. Selectively only when reproducing with 0.1 seconds to 0.0 seconds until the reproduced image signal voltage stabilizes.
Make sure to mute the reproduced image signal for about 9 seconds.

Furthermore, in this embodiment, the moving speed of the head 3 is detected, and when the track moving speed is low, the carrier frequency of the signal reproduced by the head 3 is determined each time the head moves, and an appropriate image signal is output. On the other hand, when the track movement speed is high, if the characteristics of the demosimulator 8 are changed, priority is given to preventing screen disturbances due to malfunction of the synchronization separation circuit of the motor 16 due to instability of the image signal, and the characteristics of the demosimulator 8 are not changed. .

Note that by not changing the characteristics of the demodulator, the output level of the demodulator 8 will fluctuate, and the brightness of the image reproduced on the monitor 16 will change, but this will not be noticeable because the track movement speed is high. .

Next, the operation of the embodiment configured as above will be explained using the flowcharts from FIG. 2 onwards.

First, when the power of the apparatus of this embodiment is turned on by a power switch (not shown), the flow starts and the head feeding mechanism 4 is activated so that the head 3 accesses the outermost track on the magnetic sheet l, that is, the first track. move it using (S
IO). Next, increase the track feed speed to 2 tracks/
seconds, and the demodulation characteristics of the demodulator 8 are set for high band H (S12). Note that this setting may be for low band L. . The key is to make it uniquely determined by one or the other. Next, it is determined whether or not the switch 20-1 instructs to change the track feed speed (speed) (S14). In this embodiment, the track feed speed is determined by the UP/DOWN switch 20-2.
2 tracks, 5 tracks per second while is on,
10 track feed rate and O track i.e. UP/DOW
When the N switch 20-2 is turned on, the head 3 is turned off for l tracks until the switch is turned off and turned on again.
The speed at which it moves can be set. Each time the switch 20-1 is turned on in S14, the controller 12 changes the track feed speed to 2 tracks/sec, 5 tracks/sec, lO
tracks/second.

0 tracks/sec cyclically (316
).

Further, in S16, the controller 12 drives the character generator 28 to display the set track feeding speed on the screen of the monitor 16. This allows the user to know the set track feed speed. Moreover, since such a display is superimposed with the reproduced image signal on the monitor 16 without using a special display element, the display can be performed with a simple configuration. In S14, when change of the track feeding speed by the switch 20-1 is not instructed, the flow moves to 818, and it is determined whether or not the UP/DOWN switch 20-2 is turned on.

When the UP/DOWN switch 20-2 is turned on, the exits of the detection circuit 24, ID detection circuit 26, and discrimination circuit 11 are determined to determine whether the track being accessed by the head 3 is unrecorded or recorded. If so, it is detected whether an image signal is recorded or not, and if an image signal is recorded, it is detected whether a high band H signal or a low band signal is recorded. (S20). When it is determined that an image signal is recorded, the characteristics of the demosulator 8 are changed to match the recording characteristics according to the detection result of either high band H recording or low band recording, and the characteristics of the LED 30 are changed. Display (S22). Furthermore, the results of the detection and discrimination in S20 are stored in the area of the memory 17 corresponding to the track being reproduced by the head 3 (S24).

After S24 is executed, the flow returns to S14. 81
8, when it is detected that the UP/DOWN switch 20-2 is turned on, it is determined whether the set track feed speed is O tracks/second, and if it is 0 tracks/second, the UP/DOWN switch 20-2 is turned on. The flow moves to Fig. 4, and in cases other than O tracks/sec, the flow moves to Fig. 5 (2).

The explanation will be given below with reference to FIG.

In FIG. 4 330, the head 3 is moved by a track (S30), and it is determined whether or not information has already been written in the area of the memory 17 corresponding to the track to which the head 3 has been sent. If not written to S42, the process branches to S34.

In S34, steps similar to those described in FIG. 2 820 are executed, and when this determination is completed, the flow moves from S36 to S38 and S40.

In S38 and S40, steps similar to S22 and S24 are executed, and the flow returns to FIG. 2C.

Next, a case where the process branches to S42 at S32 will be explained. In S42, the head 3 reads the information written in the area of the memory 17 corresponding to the newly accessed track 330, and compares it with the information of the track that the head 3 was accessing before executing S30. If the two pieces of information are different, for example, one indicates that a high band H signal is recorded, and the other indicates that a low band signal is recorded, the flow branches to S44. If both pieces of information match, the flow branches to ◎ in Figure 2.

Steps similar to 522 are executed at S44.

In S44, the controller 22 changes the characteristics of the demosimulator 8, but the demosimulator 8 does not have high responsiveness to such changes, and the image will be distorted. Therefore, in S46, the mute function shown as 14 in FIG. Activate the circuit and mute the monitor 16. After a time has elapsed to allow for the responsiveness of the demosimulator 8, the flow moves from 348 to 850, the mute is released, and the flow moves to ◎ in FIG.

Next, the flow executed when the process branches to {circle around (2)} at 328 in FIG. 2 will be described using FIG. 5.

In the flow shown in FIG. 5, the characteristics of the demodulator 8 are changed when the set track feed rate is 2 tracks per second, and the characteristics of the demodulator 8 are not changed when the set track feed rate exceeds 2 tracks per second. .

The determination mechanism of this controller 12 will be explained based on the flowchart of FIG. 5 during automatic feeding.

First, in S50, the set track feed speed is 2 seconds per second.
Determine whether the setting exceeds the frame. At this time, if the frame rate exceeds 2 frames per second, the process proceeds in the "Y" direction, and in S52, the head 3 is moved by one track without carrying out carrier discrimination. In this case, the UP/DOWN switch 20-2
The head 3 is sent to the inner circumferential side or the outer circumferential side on the sheet l depending on the state of the operation. On the other hand, if the frame rate exceeds 2 frames per second in the "N" direction, the head 3 is moved UP/DOWN at the track feed speed set in 855, that is, 2 tracks/sec.
Move it in the direction instructed by the N switch 20-2. S
55 is followed by step S20 and step S57 similar to step S22.
Execute 58. That is, when track feeding is performed at a speed of 2 tracks/second, the recording state of the track accessed by the head 3 is determined every time the track accessed by the head 3 is changed, and the demosulator 8
change the demodulation characteristics of Then UP/DOWN with S60
It is determined whether the switch 20-2 is turned on, and if it is turned on, the flow returns to S55.

Also, S54 is executed immediately after S52, and UP/D
If the OWN switch 20-2 is turned on, S52 is executed again.
is executed.

Therefore, in this embodiment, when the track feed speed is 5 tracks/second or more, S52 to S54 are executed, and as in the case of 2 tracks/second, S55. S57.
S58 is never executed.

That is, if the track being accessed by the head 3 is changed in a time shorter than the response time when the characteristics of the demosimulator 8 are changed, the characteristics of the demosimulator 8 are not changed so that the characteristics on the monitor 16 are changed. Prevents disturbances in images played back.

In addition, in the flow shown in FIG. 5, S55 follows S50.
．． S57. Although S58 was originally executed, S32. shown in FIG. 4 was executed instead. S34. S36. S38.
S40°S42. S44.546c, S48.5
After executing step 50, the flow may proceed to step S60 without returning to step C.

In the above embodiments, the determination circuit 11 is used to determine whether the recorded image signal is recorded in the high band H or low band L, but the determination is not limited to this, and the controller 12 may also perform the determination. .

An example of actual flow in such a case will be explained using FIGS. 6 and 7.

FIG. 6 is a block diagram for the controller 12 to discriminate between high band H and low band L, and FIG.
Replaced in place of 11. 12 in Figure 6
1 is High Band BPF, 122 is Low
Band BPF, 123, 124 are smoothing circuits, 12
5, 128 is an A/D converter, 127 is a changeover switch, and the reproduced RF signal Sl from the amplifier 6 is set to High and L.
ow BandBPF. As shown in Figure 3, Low Band BPF is 6~
7, 5 MHz (Cl), High Band
The BPF is configured to extract signal components from 7.7 to 10 MHz (C2). The signals passed through each BPF are smoothed, A/D converted, and taken into the controller 12. Here, since the reproduced signal is either High or Low, when one of the signals is reproduced, the signal 34. is always output from the envelope detection section. One of S5 is thick (becomes) in terms of level.

The signal S4. sent to the controller 12. S5 is processed according to the flowchart in FIG. That is, S4 and S5 are sequentially fetched (101, 102), and compared (103). After the comparison, the unrecorded level set in the controller 12 is compared (104, 1).
07), if it is larger than this level, the mode resulting from the comparison in 103 is stored in the memory 6 (105).

If it is smaller, it is determined that the current track is unrecorded, and information about the unrecorded track is stored in the memory 6.

As described above, the controller 12 can directly determine whether or not a track accessed by the head 3 is recorded and whether an image signal is recorded in the high band H or low band L recording. According to such a configuration, the envelope detection circuit 24 can be made unnecessary.

In this embodiment, the demodulation carrier frequency given to the demodulator 8 is changed as a method of changing the characteristics of the demodulator 8.
may have a block configuration as shown in FIG. In FIG. 8, 131 is a high band H signal processing circuit; 132
1 is a low band L coarse signal processing circuit, 133 is a changeover switch, and a video signal processed in each mode is selected according to a mode signal S3 indicating the determined high band H/low band L from the controller 12. and is output to the mute circuit I4.

Further, in this embodiment, the head 3 accesses the high band H
By storing the information on the track for which the 10 Uband L has been determined in the memory, no time is required for such determination from the second time onward, so that smooth video output and mode display can be performed.

Further, in this embodiment, the high band H and low band L are determined for the track accessed by the head 3 for reproduction, but the present invention is not limited to this.
During this time, the head 3 may sequentially access all the tracks on the magnetic sheet 1, and the results may be stored in advance before entering the reproduction state. During this sequential access, the monitor 16 may be muted by the mute circuit 14.

According to this embodiment, even if image signals are modulated with different carrier frequencies and recorded in different frequency bands on the same magnetic material, the image can be reproduced without being distorted, causing discomfort to the user. Giving something has the effect of becoming nothing.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to suppress disturbances in the output that occur when switching the characteristics of the processing means,
Good and stable playback can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a playback device according to an embodiment of the present invention, and FIGS. 2, 4, and 5 show a controller 12 shown in the first embodiment.
FIG. 3 is a diagram showing the frequency bands of high band H recording and low band recording and the frequency characteristics of the filter 10 shown in FIG. 1. FIGS. 8 is a block diagram showing the configuration of a modified example of the demosimulator 8. FIG. l ・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・Magnetic sheet 2・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・Spindle motor 3・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・Head feed mechanism Motor control circuit Preamplifier equalizer Demo simulator Amplifier band bass filter carrier Frequency discrimination circuit Controller Timer memory output Buffer Monitor memory

Claims (3)

[Claims] (1) A means for reproducing information recorded in different bands in each area of a medium, a processing means for processing and outputting a reproduced signal of the means with characteristics according to the band, and when switching the characteristics of the processing means. and means for suppressing disturbances in output that occur during playback. (2) The playback device according to claim 1, wherein the suppressing means is a means for muting output disturbances that occur during the switching. (3) The suppressing means is a means for preventing the switching from being performed when the playback speed for each area of the playback means is higher than a predetermined speed, thereby suppressing disturbances in the output that occur during the switching. A device according to claim 1, characterized in that: