JPS63298863A - Picture reproducing device - Google Patents

Abstract

PURPOSE:To surely reproduce all plural kinds of picture information recorded in different recording modes by applying switching control to the operating state of a read means and a recording medium driving means in response to the recording mode of picture information recorded on a recording medium. CONSTITUTION:When an analog/digital discriminating circuit 28 discriminates the recording of an analog signal, a signal obtained from two video heads H-2, H-4 fitted to a rotary cylinder 12 opposed to each other is fed to a high pass filter and a lower pass filter respectively via amplifiers 19B, 19D. Then a video output is obtained through a changeover switch. Thus, the operating state of a reproducing means and driving means is set in response to the output of the analog/digital discriminating circuit 28 to discriminate the signal mode (analog/digital) recorded on the magnetic tape in this way. Thus, all plural kinds of picture information recorded in different recording modes are reproduced surely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reproducing device that reproduces image information recorded on a recording medium.

[Prior art J] As currently known analog VTRs (video table coders), there are 17
2-inch home VTRs are widely known. Other V
Commercial 1-inch VTRs are used as TRs, but in any case, all of these VTRs record analog signals.

Furthermore, since the format of recorded signals in digital VTRs is completely different from that in analog VTRs, it has not been considered at all to reproduce magnetic tapes recorded by analog VTRs.

(Hereinafter in the margin) [Problems to be solved by the invention] However, considering the current situation where 172-inch VTRs for home use are extremely popular, it is possible that not only digital VTRs but also analog VTRs will coexist, except in the distant future. becomes indispensable.

In other words, an inconvenience arises in that an analog VTR must be used to reproduce previously recorded analog images, and a digital VTR must be used to reproduce digital images.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image reproducing apparatus that can reliably reproduce a plurality of types of image information recorded on a recording medium using different recording modes.

(Hereinafter, blank) Means for Solving Problem E] The image reproducing apparatus according to the present invention is an apparatus for reproducing image information from a recording medium on which image information is recorded in a plurality of different recording modes. , a reproduction means for reproducing image information recorded on a recording medium, a driving means for driving the recording medium, a determining means for determining a recording mode of the image information recorded on the recording medium, and the determining means. and control means for setting the operating state of the regeneration means and the drive means in response to the output of the drive means.

(Hereinafter, blank space) [Operation J With the above-described configuration, the present invention can switch and control the operating states of the reading means and the recording medium driving means according to the recording mode of the image information recorded on the recording medium. It becomes like this.

(Hereafter, margin) [Example 1 Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is a block diagram showing an embodiment of an archlog/digital VTR to which the present invention is applied.

In this figure, 2 is an analog video signal input terminal, SWI is a selector switch for selecting analog recording mode or digital recording mode, 4 is an analog/digital (A/[)) converter, and 6 is an analog/digital (A/[)) converter.
7 is a recording digital signal processing circuit; 7 is a recording analog signal processing circuit; 8 is a signal switch/distributor; 1O^ to IOE are amplifiers; 12 is a rotating head cylinder.

H-1-H-5 are video heads arranged every 90'', and each head has an azimuth angle as shown in the figure.Among these video heads, H-4 and H-2 are 180@ These are opposite azimuth heads, and are used when recording/reproducing normal analog signals or when used as an aspect of recording/reproducing digital signals (details will be explained later with respect to Figure 6 (B)). .

14 is a cylinder motor that rotates the cylinder at 1800 rpm (standard speed) or 3600 rpm (double speed), 16A and 15B are loading posts, 17 is a capstan, 18 is a magnetic tape, 19A to 19E are amplifiers, 20 is a signal switch/ coupler, 22 is a digital signal processing circuit for reproduction, 24 is a D/A converter, SW2 is a changeover switch for human video signals, 26 is an analog signal processing circuit for reproduction, 28 is a signal format (analog) recorded on a magnetic tape; 30 is a capstan control circuit, 32 is a cylinder motor control circuit, and 34 is a system controller.

FIG. 2 is an operational block diagram when recording/reproducing the VTR shown in FIG. 1 in digital mode. In this diagram,
The configuration of digital signal processing paths 6 and 22 is shown in more detail.

The digital mode recording/reproducing operation described above is as follows.

During recording, a human video signal is first introduced into the A/D converter 4 and converted into digital data.

If the encoding method at this time is composite encoding according to the NTSC method, the sampling rate is set to three times (3fsc) or four times (4fsc) the color subcarrier frequency (fsc), and the quantization level is set to 7. Preferably, 1 bit or 8 bits is selected.

The digital data obtained in this way is approximately 100Mb.
ps data rate, so for example V
The information band is too wide to be recorded on a cassette tape such as H5. Therefore, a band compressor 6^ is used to reduce the amount of data to about one-fourth. Specifically, do the following.

Now, assuming that the effective screen is 76%, the amount of information is compressed to 1/2 using a well-known subsample, and llPCM (differential PC
7 bits of information per sample is compressed to 4 bits by M encoding. Now, if we calculate the power increase ratio by adding redundant code to the next stage 6B as 15%, then 0.76 x O
, 5x 4/7 x 1.15 to 1/4, and according to the above method, the total amount of information can be compressed to one-fourth.

The redundant code addition circuit 6B adds an error correction code as a measure against transmission errors and dropouts associated with magnetic recording/reproduction, and also adds blink 10 words for special reproduction.
Add synchronization pulse for data reproduction.

The next stage modulation circuit 6C performs digital code conversion with low frequency suppression characteristics so as to obtain a spectrum suitable for the characteristics of the electromagnetic conversion system (rotary transformer, azimuth head, etc.) 6 Specifically, the image signal is converted into a digital code with low frequency suppression characteristics. It is preferable to use adaptive coding that utilizes the characteristics of , nm conversion that adds redundant codes, or the like. In this embodiment, since DPCM encoding is performed, an adaptive encoding method cannot be used, so an nm (8-10, 8-9, etc.) conversion method is adopted.

Then, the track formation process (Fig. 6(B)), which will be described in detail later,
.about. will be explained with reference to FIG. 6(D)), digital data is recorded on the magnetic tape 18.

FIG. 3 shows an example of a track pattern formed on the magnetic tape 18.

At the time of reproduction, waveform equalization processing is performed in the demodulation circuit 22C, and a conversion inverse to that at the time of modulation (a reverse lookup table may be used) is performed to restore the original code sequence.

The error detection/correction circuit 22B performs error detection and corrects correctable errors. On the other hand, for errors that exceed the correction ability, data interpolation is performed using other correct data. Further, when interleaving processing is performed in which data strings are recombined to prevent burst errors as error correction processing during recording, de-interleaving processing is performed to restore the original data string. As the error detection and correction code, for example, a ClR5 (cross-interleaved Reed-Solomon) code can be used. However, when special playback and editing are taken into consideration, the range of interleaving is limited because it is not possible to perform interleaving processing on all data strings.

The band expansion circuit 22A performs the opposite conversion to that of the band compressor 6A. In other words, PCM data is generated from DP[:M encoded difference data (4 bits → 7 bits)], and data corresponding to pixels thinned out by subsamples is interpolated with other data to generate a video signal. A blanking part such as a synchronization signal is added to the

In the final stage D/A converter 24, the thus reproduced digital data is returned to an analog signal and converted into a signal suitable for a general monitor television.

In the explanation of the operation during reproduction so far, it is assumed that the analog/digital discrimination circuit 28 has previously determined that digital processing has been recorded on the magnetic tape 18.

FIG. 4 is a block diagram showing the detailed configuration of the reproduction analog signal processing circuit 26 shown in FIG. 1. In this figure, 2
68 to 26C are blocks for reproducing luminance signals. That is, 26A is a high pass filter (HPF) that extracts the FM signal recorded on the magnetic tape 18;
26B is an FM demodulator for restoring black and white images, 26G
is a delay line for time alignment with the color signal. The other blocks 26D to 26F are blocks for reproducing color signals. That is, 26D is a low-pass filter that extracts a low-pass conversion color signal, and 26E is a frequency conversion (767kl+□
-3, '58 MHz), and 26F is a band pass filter (BPF) for removing unnecessary frequency components generated due to the frequency conversion. Also, 2
6G is a mixer and restores composite color television signals.

However, as a premise for setting the operation mode shown in FIG. 4, it is necessary to identify in advance by the analog/digital discrimination circuit 28 that an analog signal is recorded on the magnetic tape 18.

That is, when the analog/digital discrimination circuit 28 determines that an analog signal is recorded, the two video heads H-2 and H-4 (with opposite signs of azimuth The signals obtained from the
It is supplied to a high-pass filter 26A and a low-pass filter 26D via B and 19D. Since the subsequent signal processing process is well known, a description thereof will be omitted.

Thus, a video output is obtained via the changeover switch SW2.

FIG. 5 is a block diagram showing another embodiment for reproducing analog signals from magnetic tape. In this embodiment, the video heads )l-2, )l described in connection with FIG.
-4 and amplifier 1911.191), but
The reproduction analog signal processing circuit 26 is not used. Instead of using this analog signal processing circuit 26, in this embodiment shown in FIG. 5, an A/D converter 4, a digital signal processing circuit 22. Digital processing is performed using a D/A converter 24. So, in this example,
Instead of using a separate circuit as a to/Ill converter, an existing one is used in the recording side circuit for digital signal recording.
The equipped A/D converter 4 (see Fig. 1) is shared. Similarly, the reproduction digital signal processing circuit 22 and D
/A converter 24 (see FIG. 1) is used as is.

In order to realize such sharing, it is necessary to connect the above blocks in cascade using a changeover switch or the like (not shown), but this can be realized using ordinary switching technology.
Detailed explanation will be omitted.

In this way, by digitizing and processing the analog signals obtained from video heads H-2 and H-4, various image processing (for example, stop motion display,
In addition to being able to perform overlapping display and two-split display, the A/D converter and the like necessary for a digital VTR can be shared, so there is no increase in manufacturing costs.

FIGS. 6A to 6D are diagrams for explaining the relationship between the rotation speeds of the rotary head cylinder 12 and the capstan 17 and the recording/reproducing track pattern. The numbers “1” to “5” in the track pattern shown on the right side of this figure are
Indicates that video heads H-1 to H-1 are currently located at the positions shown. Furthermore, the shaded portion in the track indicates that tracing has already been completed.

FIG. 6 (8) is an explanatory diagram of operations for recording/reproducing analog signals. Here, the rotating head cylinder is
Set the speed to 800 rpm (standard speed: XI) and rotate the capstan at the standard speed (x1). In addition, reverse azimuth heads H-2 and H-4, which are 180° opposed to each other, are used as video heads. Here, the rotational speeds of the rotating head cylinder and the capstan are controlled by a system controller 34 (see FIG. 1, 8).

FIG. 6(B) is a diagram illustrating an operation mode for recording/reproducing digital signals. In the recording/reproducing mode shown in this figure, 1. It is controlled by a system controller 34 (see FIG. 1). Also, the recording/playback mode shown in this figure is recorded as digital mode.
/ This is the longest time mode for playback. The video head is a 180° video head used during analog recording/playback.
Opposing reverse azimuth heads H-2 and H-4 are used.

FIG. 6(C) shows the operation mode when recording/reproducing digital signals using four video heads H-4, 1-5, H-1, and H-3 arranged 90 degrees apart. FIG. In this aspect, the system controller 34
The rotating head cylinder is set to standard speed (x1) and the capstan is set to double speed (x2).

The head position at this time is as shown on the right side of the figure.

For example, when tracing of head H-3 is completed,
The trace of head H-1 is also half completed. At the same time, tracing of head H-5 is newly started. As mentioned earlier, these four video heads are
They have opposite azimuth angles.

FIG. 6CD) is a diagram showing an operation mode when recording a digital image with the highest resolution. In this aspect, the system controller 34 controls the rotary head cylinders to
The capstan is set to double speed (x2) and quadruple speed (x4). In addition, among the traced completed parts (hatched parts) shown on the right side of this figure, ""(5)" and "(4)"
The parts indicated with are H) I-5 and H-4, respectively.
This indicates that tracing is complete.

In the digital recording/reproducing modes shown in FIGS. 6(B) to 6(D) described above, since the amount of information recorded/reproduced is different,
It is necessary to change the contents of the encoding process in the band compressor 6A and the restoration process in the band expander 228 (quantization level number, bit rate, etc.) as appropriate.

Furthermore, the widths of the tracks shown in FIGS. 6(A) to 6(D) are all the same. In other words, in this embodiment, the head ■
The physical shapes of -1 to H-5 are made uniform so that they can be applied to both analog and digital systems.

For Figure 6 (A) to ([+), move the video head to 9
Although the explanation has been made using a four-head type arranged at intervals of 0@, various tracks can also be formed by rotating two 180'' opposing heads at high speed as shown in FIG.

FIG. 7 is a diagram showing heads A and B facing each other by 180° and having an azimuth angle of ±6°. Now, by setting the rotational speed of the rotary head cylinder 40 to the standard speed (1800 rpm) and also setting the capstan to the standard speed, the tracks shown in FIGS. 6(8) and 6(B) can be formed.

Also, both the rotating head cylinder and capstan are 2
By rotating at double speed, the track shown in FIG. 6(C) can be formed.

Furthermore, the rotating head cylinder and capstan are both 4
By rotating at double speed, the track shown in FIG. 6(D) can be formed.

Next, various circuit configurations of the analog/digital discrimination circuit 28 (see FIG. 1) will be explained with reference to FIGS. 8 to 12.

The circuit shown in FIG. 8 discriminates between analog recording and digital recording by identifying whether or not a color burst signal is recorded on the magnetic tape 18. In other words, when recording digitally, a low-frequency suppression modulation method is used, so there are few low-frequency components;
Since a color burst signal is included during analog recording, a difference occurs in the level difference of the low frequency component. Therefore, in order to detect such a level difference, the configuration shown in this figure is adopted.

In FIG. 8, 42 is a band pass filter (BPF) that manually inputs the RF input signal obtained through the video head and passes a predetermined low frequency (700 kHz or less) signal around the carrier frequency of the low frequency converted color signal. ). 44 is a level detector, and 46 is a comparator that compares it with a threshold value Th and sends out a signal at H (high) level or L (low) level.

As a result, when the comparator 46 outputs an H level signal, it is determined that analog recording is being performed, while when the L level signal is being output, it is determined that digital recording is being performed.

The circuit shown in FIG. 9 discriminates between analog recording and digital recording depending on whether or not the horizontal synchronizing signal Lync is included in the demodulated luminance (Y) signal. In this figure, 26B is the FM demodulator shown in FIG. 4, which sends out a demodulated luminance signal. 50 is a horizontal synchronizing signal extraction circuit, which outputs a synchronizing pulse a. 52 is a counter that counts the synchronization pulse a; 54 is a 17N frequency divider that outputs a reset pulse b to the counter 52; and 56 is a comparator that determines whether the output of the counter is "N" or not. .

According to this circuit, the output of the comparator 56 is Analog recording when N Digital recording when ≠N It can be determined that this has been done.

The circuit shown in FIG.
This is used to distinguish between analog recording and digital recording.

Note that the term "clock run-in" here refers to a signal for synchronizing the oscillator inside the VTR with the clock on the tape, and the term "synchronization pulse" refers to a signal that indicates the recording start point of digital image data. .

In FIG. 1O, 58 is a preamplifier that manually inputs the output signal from the video head, 60 is a waveform equalization amount, 62 is a phase lock circuit, 64 is a gate circuit, 66 is a synchronization signal generation circuit, and 68 is a data processing circuit. It is. Further, a is a PLL rotor flag, and b is a synchronization pulse (sync) detection signal. The phase lock circuit 62 includes a phase comparator 62^, a voltage controlled oscillator 62B, and a comparator 62, as shown at the bottom of the figure.

Analog recording/digital recording can be determined based on the presence or absence of the PLL rotor flag a or the 5sync detection signal.

The circuit shown in FIG. 11 performs a digital This is to determine whether it is a record number or not. In other words, error detection and
When supplied to the correction circuit 22B, since error detection is performed continuously, it is determined that an analog signal is recorded.

In FIG. 11, 22B is an error detection/correction circuit that outputs an error flag every time an error is detected, 70 is a counter that counts the number of error flags, and 72 is a comparator. As a result, when the count value of the counter 70 is greater than N (threshold value), it is determined that analog recording is being performed, and otherwise, it is determined that digital recording is being performed.

In addition to the control track (CTL) servo method described so far in this embodiment, it is also possible to adopt a method in which a servo pilot signal is superimposed on each track.

Further, in the conventionally known servo pilot signal system, pilot signals f and -f4 of predetermined frequencies are sequentially written for each track in a wave number region lower than the low frequency conversion color signal. On the other hand, since digitally recorded data is low-frequency suppressed, there are no low-level signal components in the frequency domain of the pilot signal.

Therefore, in one embodiment of the present invention, as shown in FIG. 12, in addition to the four types of pilot signals f, ~f4, a signal "foo" indicating that the signals are "digitally recorded" is recorded in advance. put. The frequency spectrum at this time is as shown in FIG. Furthermore, when performing DTP (dynamic track following) control to make the video bed follow the track using the four types of pilot signals f1 to f4, a conventionally known method can be used. , the explanation is omitted.

FIG. 14 shows the pilot signal f. FIG. 3 is a circuit diagram of a circuit for detecting analog recording/digital recording. In this figure, 74 is an f0 detector that detects the presence or absence of a pilot signal f0, 76 is a bandpass filter that passes signals near the clock frequency, and 78 is a bandpass filter that passes signals near the clock frequency. a comparator that outputs a logic “1” signal when it has a level; 80;
The output level of the bandpass filter 76 is the threshold value Th2
Comparator 82 outputs a logic “1” signal in the above cases.
is an and gate. When a logic "1" signal is output from the AND gate 82, it can be determined that digital recording is being performed on the magnetic tape 18.

(Hereafter, blank space) [Effects of the Invention] As explained above, according to the present invention, the operating states of the reading means and the recording medium driving means can be switched and controlled according to the recording mode of the image information recorded on the recording medium. With this configuration, it is possible to realize an image reproducing apparatus that can reliably reproduce all of a plurality of types of image information recorded on a recording medium using different recording modes.

(Hereafter, margin)

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an entire embodiment of the present invention, FIG. 2 is a block diagram showing operations in digital recording/digital playback mode, and FIG. 3 is a diagram showing an example of a digitally recorded video track. Figure 4 is a block diagram showing operations in analog playback mode, Figure 5 is a block diagram showing other operations in analog playback mode, and Figures 6 (A) to (D) are implementations shown in Figure 1. Figure 7 shows a video track formed by example, 180°
A diagram showing opposing reverse azimuth heads; Figure 8 is a block diagram for determining analog/digital based on the presence or absence of color burst; Figure 9 is a block diagram for determining analog/digital based on the presence/absence of a horizontal synchronization signal; Figure 10 is a block diagram for distinguishing between analog and digital based on the presence or absence of a polygon or synchronization pulse. Figure 11 is a block diagram for distinguishing between analog and digital based on the magnitude of error rate. Recorded pilot signal f. -f4; FIG. 13 is a spectrum diagram showing the relationship between the pilot signal and the video signal; and FIG. 14 is the pilot signal f. FIG. 2 is a block diagram for performing analog/digital discrimination based on the presence or absence of . 4...A/D converter, 6...Digital signal processing circuit for recording, 8...Switching/
Distributor, 12... Rotating head cylinder, 16A, 16B... Loading post, 18...
・Magnetic tape, 20...Switcher/coupler, 22...Digital signal processing circuit for reproduction, 24...D
/A converter, 26... Analog signal processing circuit for reproduction, 28... Analog/digital discrimination circuit, 30... Capstan control circuit, 32... Cylinder motor control circuit, 34... System controller. Fig. 7 ≧ 2 < et al. Fig. 12

Claims (1)

[Scope of Claims] 1) An apparatus for reproducing image information from a recording medium in which image information is recorded using a plurality of different recording modes, the apparatus comprising: a reproducing means for reproducing image information recorded on the recording medium; , a driving means for driving the recording medium, a determining means for determining a recording mode of image information recorded on the recording medium, and an operation of the reproducing means and the driving means in response to an output of the determining means. An image reproducing device comprising: a control means for setting a state.