JP3153268B2 - Truck identification 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 track discriminating apparatus suitable for use in, for example, an apparatus for reproducing a video floppy (magnetic disk).

[0002]

2. Description of the Related Art In an electronic still video camera, not only a video signal can be recorded on a magnetic disk, but also an audio signal can be recorded as necessary.

FIG. 12 is a block diagram showing an example of the configuration of a conventional track discriminating apparatus for such a magnetic disk.

A signal reproduced by the head 1 is amplified by a reproduction amplifier (PB AMP) 2 and then a high-pass filter and equalizer (HPF & EQ) 3, a low-pass filter (LPF) 4, and a band-pass filter (B
PF) 5.

[0005] The high-pass filter and the equalizer 3
The input signal separates and equalizes high-frequency components and outputs the same to the luminance signal demodulation circuit 6. The luminance signal demodulation circuit 6 FM-demodulates the input signal and outputs the result to the luminance signal processing circuit 10 and the audio signal processing circuit 9. The luminance signal processing circuit 10 processes the input demodulated luminance signal and outputs the processed signal to the adder 13. The audio signal processing circuit 9 processes the input demodulated audio signal and outputs the processed signal to a circuit (not shown) via the switch 14.

The audio signal includes a flag indicating start or end and various control codes. When the audio signal processing circuit 9 detects these flags and control codes, the detection is performed. The result is output to the CPU 12.

[0007] The low-pass filter 4 separates a low-frequency component (FM color signal component) from the input signal and outputs it to the color signal demodulation circuit 7. The color signal demodulation circuit 7 demodulates the input FM color signal and outputs a demodulated output to the color signal processing circuit 11. The color signal processing circuit 11 processes the input demodulated color signal and outputs it to the adder 13.

The band pass filter 5 separates a signal (ID signal) of a predetermined frequency band from the input signal, and
Output to the demodulation circuit 8. The ID demodulation circuit 8 demodulates the ID signal and outputs the demodulation result to the CPU 12. The CPU 12 generates a character signal or the like corresponding to the ID signal as needed,
Output to the adder 13. The ID signal includes information such as the track number and the recording date and time of the video signal.

An adder 13 adds the video signals from the luminance signal processing circuit 10, the chrominance signal processing circuit 11, and the CPU 12, and outputs the result to a circuit (not shown) via a switch 14.

The CPU 12 determines whether the track being reproduced is a track on which a video signal is recorded or a track on which an audio signal is recorded, and controls the switch 14 according to a flowchart shown in FIG. .

That is, the CPU 12 reproduces a magnetic disk (not shown) by the head 1 (step S).
1), the presence or absence of an ID is determined from the output of the ID signal demodulation circuit 8 (step S2). Since the ID (DPSK) signal is recorded on the video track (track on which the video signal is recorded), detection of this ID means that the reproduction track is a video track.
Accordingly, at this time, the CPU 12 opens the contact on the upper side of the switch 14 in the drawing and mutes the audio output (step S4).

On the other hand, when the reproduction track is an audio track, a flag or a control code is recorded therein. When these flags or control codes are detected, the reproduction track is an audio track (a track on which an audio signal is recorded). Mute the signal (steps S3, S
5).

In this manner, a correct reproduction signal is automatically selected and output regardless of whether the reproduction track is a video track or an audio track.

[0014]

As described above, the conventional apparatus is capable of determining whether or not a flag or a control code is included in an audio track or an ID in a video track.
A video track or an audio track is determined based on the presence or absence of a signal. Therefore, in order to determine the track, the output from the audio signal processing circuit or the ID signal demodulation circuit must be used, and there is a disadvantage that it takes a relatively long time.

The present invention has been made in view of such a situation, and it is an object of the present invention to easily determine a reproduction track without using an audio signal processing circuit or an ID signal demodulation circuit.

[0016]

A track discriminating apparatus according to the present invention comprises a reproducing means for reproducing a video track on which a video signal including a synchronization signal is recorded or an audio track on which an audio signal is recorded ; Synchronous signal component from output
Synchronizing signal detecting means for detecting the
A predetermined period shorter than the period in which the synchronization signal of the image signal is detected
The output frequency of the detection signal is counted in
If the number is too small, it is determined that the video track is being played
When the output frequency is relatively high, the audio track is played.
And a determination unit for determining that the operation has been performed .

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the operation of this apparatus, the characteristics of a magnetic disk and video and audio tracks recorded thereon will be described.

As shown in FIG.
In this case, the outer track is the first track, and the innermost track is the 50th track. Of these, an FM video signal is recorded on a predetermined one to form a video track, and an FM audio signal is recorded as an audio track.

The audio track is divided into four sectors as shown in FIG. 5, and independent information is recorded in each sector. The video track (the video track is not divided into sectors) has a FM-modulated video signal and a DPSK (Differential) signal.
neutral Phase Shift Keying)
The modulated ID code is frequency-multiplexed and recorded.
In the audio track, a time-axis-compressed audio signal is time-division multiplexed together with a control code, and further FM-modulated and recorded.

One field of a video signal is recorded on one track. In the NTSC system, one image is displayed in two fields (one frame).
The standard is a frame mode in which one image is displayed on two tracks, but a field mode in which one image is displayed in one field to record more images is provided. It has become.

FIG. 6 shows the bit arrangement of the ID code recorded together with the video signal. The vertical synchronizing signal interval T is the time of one rotation of the disk, and the image is switched with the image of the next track at the switching position. It is supposed to be. The periods T1, T7, and T8 are margin periods, and the period T2 is an initial bit period indicating a start point.

In the period T3, field / frame information, that is, selection information for use in the above-described frame mode or in the field mode is recorded. In order to record image information of (2 fields), information indicating whether the information is recorded on an inner track or an outer track is also recorded.

In a period T4, information of a track number where image information is recorded is recorded, in a period T5, date information is recorded, and in a period T6, information defined by a user can be recorded. In this embodiment, the number of the next video track, the reproduction time T set by the operator, and the recording mode (AV mode or normal mode (V mode or A mode)) are recorded.

The information recorded in one sector of the audio track is formatted as shown in FIG. The periods T1, T9, T10, T8, and T2 are pedestal levels indicating a reference level. During reproduction, the pedestal level is clamped to a predetermined reference level, and the data level (course) of another period is determined. Has become. Period T11
The start flag and the end flag of the period T12 are used to determine which type of type 1 to type 4 this sector belongs to, as described later, in addition to the original start and end determination.

The control code in the period T13 is used for recording various kinds of control information as described later. The overlap information in the period T3 is used to ensure the continuity of the audio information between the sectors, since the audio information is configured by information of a plurality of sectors.
The period T4 is a portion where audio information is recorded.

The sector type is identified by a combination of the polarity of the start flag and the end flag as shown in FIG. That is, when the start flag is at the high level and the end flag is at the low level, the type 1
Alternatively, type 2 is set (the type 1 and type 2 are identified later). When the start flag is at a high level and the end flag is also at a high level, the type is identified as type 3, and when the start flag is at a low level and the end flag is at a high level, type 4 is identified.

The use of this sector type is as shown in FIG. 9. The sector of type 1 indicates that the sector following the track is continued, and the sector of type 2 is specified to end on that track. A jump to a sector indicates that a type 3 sector indicates the end of the sequence, and a type 4 sector indicates that no audio information is recorded.

FIG. 10 shows an example of four sectors recorded on one track. In the first to third sectors, since the next sector follows the sector on the track, the type 1 sector is Since the fourth sector is used and the sequence ends at this sector, a type 3 sector is used.

FIG. 11 shows another example of how the four types of sectors are used. One track is composed of 0, 1, 2, and 3 sectors.
Track numbers 5, 8, 1
This is an example in which continuous audio information is recorded on each of tracks 1 and 13. Track 5 is followed by two type 1 sectors, followed by a type 2 sector, and a control code indicating that the next succeeding sector is the first sector of track 8 is recorded in the type 2 sector. .
The fourth sector of the track 5 is assigned type 4 since no audio information is recorded.

The track 8 has three type 1 sectors, the fourth sector is assigned a type 2 sector, and the control code records that the next sector is the first sector of the track 11.

The track 11 is provided with one type 1 sector and one type 2 sector, and the control code records that the next sector is the first sector of the track 13 in the type 2 sector. . The remaining two sectors of the track 11 are assigned type 4. Track 13 indicates that one type 3 sector has been allocated and that the end of the sequence there.

The remaining three sectors of the track 13 are assigned type 4 sectors. Therefore, this sequence starts from the first sector of the track 5, continues to the first sector of the track 13, and ends there.

As shown in FIG. 11, when moving to the head sector of another track in the middle of the track such as track 5, for example, the start flag of the third sector type 2 is high as shown in FIG. End flag low at level
Level , which is apparently the same as Type 1.
However, since the fourth sector is unused in type 4, it is determined that type 4 is not type 1 but type 2.

Also, when all the sectors of one track are used and then the start of another track is performed, as in track 8, type 2 of the fourth sector is apparently type 1 as described above in view of the flag configuration. However, since sector 3 is the last sector in one track, it is determined as type 2 based on this.

Next, an embodiment of the track discriminating apparatus of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of an embodiment of a track discriminating apparatus according to the present invention. In FIG. 1, portions corresponding to those in FIG. I do.

In this embodiment, the luminance signal processing circuit 1
0 (video signal processing means) is part of the sync separation circuit 2
1 (synchronization separation means) to separate the vertical synchronization signal. The output of the sync separation circuit 21 is CP
U12. Other configurations are the same as those in FIG.

Next, referring to the flowchart of FIG.
The operation will be described. When the head 1 (reproducing means) reproduces a disc (not shown), if the reproduction track is an audio track, as in the case described above, the audio signal processing circuit 9
An audio signal is output from the (audio signal processing means), and in the case of a video track, a video signal processed by the luminance signal processing circuit 10 and the color signal processing circuit 11 (video signal processing means) is output from the adder 13. .

The CPU 12 first sets the time of the built-in timer to Tm (where Tm is an arbitrary value of V / 2 <Tm <V and V is a period corresponding to one field). Monitor the output (Steps S11, S
12). When the sync separation circuit 21 generates a detection output of a vertical sync signal, the CPU 12 starts a timer (step S13). When the synchronization separation circuit 21 generates a vertical synchronization signal detection signal again before the timer elapses the set time Tm, the CPU 12 determines that the reproduction track is an audio track and turns off the lower switch in FIG. Then, while muting the video signal, turning on the upper switch in the figure to output an audio signal (steps S14 and S1).
6, S17).

When the synchronization separation circuit 21 does not generate a detection signal again until the timer measures the set time Tm, the reproduction track is determined to be a video track, and the upper switch in the figure is turned off, and the audio signal is turned off. Is muted, the lower switch is turned on, and a video signal is output (steps S14 and S15).

Next, the relationship between the type of track and the vertical synchronization signal will be described. When the currently reproduced track is a video track, the luminance signal processing circuit 10 outputs a luminance signal as shown in FIG. 3A. Accordingly, the sync separation circuit 21 outputs the sync separation output as shown in FIG. 3B once during one field period (while the disk makes one rotation).
Therefore, if the time Tm is set to a value smaller than 1 V (Tm <V), the next detection signal will not be generated until the time Tm is measured.

On the other hand, the audio track is divided into four sectors as described with reference to FIG. Therefore, when the reproduction track is an audio track, the output of the luminance signal processing circuit 10 changes to a low level or a high level at the boundary of each sector in addition to the original audio signal component as shown in FIG. 3C. Start flag or end flag is generated. Of these, the flag that changes to a low level has the property of being detected as a vertical synchronization signal by the synchronization separation circuit 21. Therefore, the output of the synchronization separation circuit 21 is output at 4 per rotation of the disk 21, as shown in FIG. Occurs several times.

[0042] The foregoing is a case where sufficient volume of the audio signal to all of the four sectors is recorded, a few examples
When an audio signal of a sufficient volume is recorded in 3.5 sectors, the output of the luminance signal processing circuit 10 and the output of the sync separation circuit 21 are as shown in FIGS. 3E and 3F. Hereinafter, similarly, the output of the luminance signal processing circuit 10 and the output of the sync separation circuit 21 are output when a low-level audio signal is recorded in 1.5 sectors or 0.5 sectors, or
3G to 3L when almost no audio signal is recorded.
Respectively.

That is, in any case, if the reproduction track is an audio track, the sync separation circuit 21 outputs at least four detection signals during one field (four sectors).

The longest time during which no detection signal is output is
As shown in FIG. 4, for example, an audio signal is recorded in the first sector (type 1 or type 2 sector), and no audio signal is recorded in the fourth sector (type 4 sector). The track (the second and third sectors may or may not be recorded with an audio signal) is reproduced from the fourth sector toward the first sector by about two sectors (V / 2). (Accurately, a period slightly shorter than two sectors). Therefore, if the time Tm is set to a time longer than two sectors (V / 2 <Tm),
During the period Tm, the detection signal is generated at least once.

After all, if the time Tm is set to V / 2 <Tm <V, if a detection signal is generated even once during that period, an audio signal is recorded, and the detection is performed once. If not, the video signal is recorded.

In this manner, the type of the track can be determined from the number (interval) of the vertical synchronization signal.

In the above description, the synchronization separation circuit 21
Is provided separately from the luminance signal processing circuit 10, but it is also possible to use the one built in the luminance signal processing circuit 10.

[0048]

As described above, according to the track discriminating apparatus of the present invention, the video track and the audio track are determined from the synchronizing signal detected during a predetermined period. The type of the track can be quickly determined without reading the ID or the control code.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a track discriminating apparatus of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a waveform diagram of an output of a luminance signal processing circuit and a sync separation circuit in the embodiment of FIG. 1;

FIG. 4 is a view for explaining a reproduction timing of a flag of a disk used in the embodiment of FIG. 1;

FIG. 5 is an explanatory diagram of a sector of a disk used in the embodiment of FIG. 1;

FIG. 6 is a diagram showing a format of a DPSK signal frequency-multiplexed with a video signal;

FIG. 7 is a diagram showing a format for one sector of a signal written to an audio track.

FIG. 8 is a view for explaining types of sector types.

FIG. 9 is a diagram illustrating functions of a sector type.

FIG. 10 is a diagram showing an example of allocation of each sector in an audio track.

FIG. 11 is a diagram showing an example in which sectors of a plurality of audio tracks are continuous.

FIG. 12 is a block diagram showing a configuration of an example of a conventional track discriminating apparatus.

FIG. 13 is a flowchart for explaining the operation of the example of FIG. 12;

[Explanation of symbols]

 Reference Signs List 1 head (reproducing means) 6 luminance signal demodulation circuit 7 color signal demodulation circuit (video signal processing means) 8 ID signal demodulation circuit (video signal processing means) 9 audio signal processing circuit (audio signal processing means) 10 luminance signal processing circuit ( Video signal processing means) 11 color signal processing circuit (video signal processing means) 12 CPU (determination means) 21 sync separation circuit (sync separation means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956 G11B 20/02

Claims (2)

(57) [Claims] 1. A reproducing means for reproducing a video track on which a video signal including a synchronizing signal is recorded or an audio track on which an audio signal is recorded, and detecting a synchronizing signal component from an output of the reproducing means to detect the synchronizing signal component.
Synchronizing signal detecting means for outputting a synchronizing signal of the video signal;
During the period of counting the output frequency of the detection signal,
When the output frequency is relatively low, the video track is
And if the output frequency is relatively high,
A discriminating means for discriminating that an audio track is being reproduced . 2. The image processing apparatus according to claim 1, wherein the discriminating means is configured to output the image of one field.
Longer than half the period during which the image signal is reproduced and
A period shorter than the period during which the video signal of one field is reproduced
When the detection signal is output one or more times between
Specially, it is determined that the audio track is being played.
The track discriminating apparatus according to claim 1, wherein