JPS63299472A - Picture reproducing device - Google Patents

Abstract

PURPOSE:To accurately discriminate the recording form of a picture information signal recorded on a recording medium, by providing a discrimination means which discriminates the inclusion of a prescribed pulse signal in the picture information signal reproduced from the recording medium. CONSTITUTION:An analog-digital discrimination circuit is constituted of a pre- amplifier 58 which inputs an output signal from a video head, a waveform equalizer 60, a phase locked loop circuit 62, a gate circuit 64, a synchronizing signal generation circuit 66, and a data processing circuit 68. And the phase locked loop circuit 62 includes a phase comparator 62A, a voltage controlled oscillator 62B, and a comparator 62. And the discrimination of recording, analog recording or digital recording, is performed based on the detection of a (clock run-in) (preamble) signal or a (synchronous pulse) recorded with digital image data. The above stated (clock run-in) shows a signal to synchronize the oscillator in a VTR with a clock on a tape, and also, the (synchronous pulse) is the signal to show the start point of the recording of the digital image data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to an image reproducing device that reproduces image information recorded on a recording medium.

[Prior Art] Currently known analog VTRs (video tape recorders) include the β system or the VIIS system.
It is widely known as a 2-inch home VTR. 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, given the current situation in which 1'72-inch VTRs for home use have become extremely popular, it seems that, apart from the distant future, analog VTII will not be the same as digital VTRs. Coexistence is becoming essential.

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.

Therefore, an object of the present invention is to provide an image information signal reproducing device that can correctly determine in which recording format image information signals recorded on a recording medium using different recording formats are recorded. It is in.

(Hereinafter, blank space) [Means for solving the problem] The image reproducing device according to the present invention can reproduce an image information signal, a digital image information signal that includes a predetermined pulse signal, or an analog image that does not include a predetermined pulse signal. A device for reproducing an image information signal from a recording medium recorded in the form of an information signal, comprising a reproducing means for reproducing the image information signal recorded on the recording medium, and a reproducing means for reproducing the image information signal from the recording medium by the reproducing means. It is equipped with analog/digital discrimination means that discriminates whether or not a predetermined pulse signal is included in the reproduced image information signal and outputs a digital discrimination signal when the predetermined pulse signal is included. .

(Hereinafter referred to as a blank space) [Operation] With the above-described configuration, the present invention determines whether a predetermined pulse signal is included in the image information signal reproduced from the recording medium by determining whether the predetermined pulse signal is included. When the signal is displayed, it can be determined that digital recording has been performed, and subsequent signal processing can be performed.

(Hereafter, margin) [Example] Hereinafter, the tree invention will be described in detail based on examples.

Figure 1 shows an analog/digital V to which the present invention is applied.
FIG. 2 is a block diagram showing an example of a TR.

In this diagram, 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 (8/DJ converter), 6 is an analog/digital (8/DJ converter)
7 is a recording digital signal processing circuit, 8 is a signal switching/distributor, 108 and 1OE are amplifiers, and 12 is a rotating head cylinder.

H-1 to H-5 are video heads arranged at 90° intervals, and each head has an azimuth angle as shown. Of these video heads, 11-4 and H-2 are reverse azimuth heads that face each other at 180 degrees, and are used when recording/playing back ordinary analog signals or as a mode when recording/playing digital signals. (6th
(described in detail later with respect to Figure (B)).

14 is a cylinder motor that rotates the cylinder at 1800 rpm (standard speed) or 3600 rpm (double speed), 16A and 16B are loading posts, 17 is a capstan, 18 is a magnetic tape, 19A-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 recorded on the magnetic tape (analog 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 using a digital mode. In this diagram,
The configurations of the digital signal processing circuits 6 and 22 are shown in more detail.

The digital mote recording/reproducing operation described above is as described below.

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

If the encoding method at this time is composite encoding according to the NTSC method, a sampling rate of three times (3fsc) or four times (4fscl) the color subcarrier frequency (fsc) is set, and the quantization level is 7 bits. Alternatively, it is preferable to select 8 bits.

The digital data obtained in this way is approximately 100Mb.
ps data rate, so for example V
Recording on cassette tapes such as HS requires a wide band of information. Therefore, a band compressor 68 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 172 using well-known subsamples, and DPCM (differential PCM
7 bits of information per sample is compressed to 4 bits by encoding. Now, assuming that the increase rate due to the addition of redundant codes in the next stage 6B is 15%, it is calculated as 0.76 Xo, 5
X4/7 Xl, 15# 1/4, and according to the above method, the total amount of information can be compressed to 1/4.

The redundant code adding circuit 6B adds an error correction code as a countermeasure against transmission errors and dropouts caused by magnetic recording/reproduction, and also adds a block ID word for special playback.
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.). Specifically, it is preferable to use adaptive coding that utilizes the characteristics of the image signal, nm conversion that adds redundant codes, or the like. In this embodiment, since DPI:M 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 22G, and conversion (reverse lookup table may be used) that is inverse to that at the time of modulation 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 Solomon) code may be used. However, when special playback and editing are considered, the range of interleaving is limited because interleaving processing must be performed 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 DPCM encoded difference data (4 hits → 7 hits), data corresponding to pixels thinned out by subsamples is interpolated with other data, and a synchronization signal is used to generate a video signal. Add blanking parts such as .

The D/8 converter 24 at the final stage returns the digital data thus reproduced to an analog signal.
Converts to a signal compatible with Q monitor TV.

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

FIG. 4 is a block diagram showing a detailed configuration of the reproduction analog im signal processing circuit 26 shown in FIG. 1. In this figure,
21iA to 26C are blocks for reproducing luminance signals. That is, 26A is a high-pass filter (IIP) that extracts Fv (H number) recorded on the magnetic tape 18.
F), 26B is an FM demodulator for restoring a monochrome image, and 26C is a delay line for time-aligning 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 (76
7k11°→3.581!112), and 2[iF is a band pass filter (BPF) for removing unnecessary frequency components generated due to the frequency conversion. Also, 26G is a mixer and restores the composite color television signal.

However, as a prerequisite 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 11-2 and H-4 (with azimuths of opposite signs) mounted opposite to each other on the rotary head cylinder 12 The signals obtained from the
It is supplied to a high pass filter 26A and a low pass filter 26D via 9B 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 2', +1-
4 and amplifiers 19B and 19D, 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.
2. Digital processing is performed using a D/A converter 24. That is, in this embodiment, instead of using a separate circuit as the Δ/D converter, the A/D converter 4 (see Fig. 1) already installed in the recording side circuit is used for digital signal recording. are doing.

Similarly, the reproduction digital signal processing circuit 22 and D/A converter 24 (see FIG. 1), which are already equipped for digital signal reproduction, are used as they are.

In order to realize such sharing, it is necessary to connect the above-mentioned blocks in cascade using a changeover switch (not shown), or it may be possible to realize it using ordinary switching technology.
Detailed explanation will be omitted.

In this way, by digitizing and processing the analog signals obtained from video heads 1 and 2 and 4,
In addition to being able to perform various types of image processing (for example, stop-ditch display, overlap display, and 9-part display), it is also possible to share the A/D converter, etc. required for a digital VTR, which increases manufacturing costs. There's nothing to do.

Figures 6 (8) to ([+1] are diagrams for explaining the relationship between the rotational speed of the rotary head cylinder 12 and capstan 17 and the recording/reproducing track pattern. Number “1°.

to 5" are video heads 11-1 to 5" respectively)
I-5 is currently located at the location shown.

Furthermore, the shaded portion in the track indicates that tracing has already been completed.

FIG. 6 (Al is an explanatory diagram of the operation for recording/reproducing analog signals. Here, the rotating head cylinder is set at 1800 rpm (standard speed: x 1), and the capstan is set at the standard speed (x 1). In addition, reverse azimuth heads 11-2 and H-4, which are 180° opposed to each other, are used as video heads.The rotational speed of the rotating head cylinder and capstan is controlled by the system controller 34 (see Fig. 1). (see ).

FIG. 6(B) is a diagram illustrating an operation mode for recording/reproducing digital signals. In the recording/reproducing mode shown in this figure, the system controller 3
4 (see Figure 1). Also, the recording/playback mode shown in this figure is recorded/played as digital modes 1 to 1.
This is the longest time mote when playing. In addition, the video head used for analog recording/playback is 180°.
Opposing reverse azimuth heads 11-2 and 11-4 are used.

Figure 6(C) shows the case of recording/reproducing digital signals using four video heads (l-4, 11-5, 11-1, 11-3) arranged at 90° angles. It is a figure showing an operation mode. In this aspect, the system controller 34
As a result, the rotating head cylinder is set to standard speed (Xi) 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, at the time the trace of H-3 was completed,
The tracing of the head 11-1 is also half completed. At the same time, tracing of the head 11-5 is newly started. Note that, as described above, these four video heads have azimuth angles in opposite directions.

FIG. 6(D) is a diagram showing an operation mode when recording a digital image with the highest resolution. In this aspect, the system controller 34 controls whether the rotating head cylinder
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 °'(41
” indicates head l-1-5 and ), respectively.
I-4 indicates that tracing is complete.

In the digital recording/reproducing modes shown in FIGS. 6(B) to (I) described above, since the amount of information recorded/reproduced is different, the encoding in the band compressor 6A and the band expander 22 are different.
It is necessary to appropriately change the contents of the restoration process in A (quantization level number, bit rate, etc.).

Further, 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 I
(The physical shapes of -1 to 11-5 are made uniform so that it can be applied to both analog and digital systems.

6(A) to 6(D) were explained using a 4-head type with video heads arranged at 90° intervals, but by rotating 2 opposing +80′ heads at high speed as shown in FIG. It is also possible to form various tracks.

FIG. 7 is a diagram showing 180' opposing heads B with an azimuth angle of ±6°. Now, by setting the rotational speed of the rotary spatula and cylinder 40 to the standard speed (1800 rpm) and also setting the capstan to the standard speed, the tracks shown in Fig. 6 (A) and (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 fewer low-frequency components, whereas
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 (BPFI) which manually inputs the RF signal obtained through the video head and passes a predetermined low frequency signal (7QOkl+2 or less) centered around the carrier frequency of the low frequency converted color signal. It is.4
4 is a level detector, and 46 is a level detector that compares it with a threshold value Th.
This is a comparator that sends out a high (high) level or L (low) level signal.

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 includes a horizontal synchronizing signal H*yn in the demodulated luminance (Y) signal. Analog recording/digital recording is determined based on whether or not the recording includes the following. 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
54 is a 1/N frequency divider that outputs a reset pulse b to the counter 52. 56 is a comparator that determines whether the output of the counter is "N" or not. It is.

According to this circuit, the output of the comparator 56 - Analog recording when N Digital recording when ≠N It is possible to determine whether this has been done.

The circuit shown in Fig. 10 uses the analog recording/digital It is used to judge records. By the way, the backrots clan in here is VT
A signal for synchronizing the oscillator inside R with the clock on the tape, and a "synchronization pulse" is a signal representing the recording start point of digital image data.

In Fig. 1θ, 58 is a preamplifier that inputs the output signal from the video head, 60 is a waveform equalizer, 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 628, a voltage controlled oscillator 628, 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 I'LL lock flag a or the 5sync detection signal.

The circuit shown in FIG. 11 performs a digital This is to determine whether it is a signal or not. That is, when an analog signal is supplied to the error detection/correction circuit 22B, since errors are detected continuously, it is determined that the 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, the count value of the counter 70 becomes N (Ll
When the dog is a dog, it is determined that analog recording has been made, and in other cases, it is determined that digital recording has been made.

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 f1 to f4 of predetermined frequencies are sequentially written for each track in a frequency 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 f1 to f4, there is a signal "f" indicating that the signals are digitally recorded.
Record in advance. The frequency spectrum at this time is
The result is as shown in Fig. 13. In addition, DTP (dynamic track control) uses the four types of pilot signals f1 to f4 to move the video head to follow the track.
Regarding the case of performing following control, a conventionally known method can be used, so the explanation will be omitted.

FIG. 14 shows the pilot signal f. FIG. 2 is a circuit diagram for detecting and determining analog recording/digital recording. In this figure, 74 is a pilot signal f. detecting the presence or absence of f. Detector, 76 is a band pass filter that passes signals near the clock frequency, 78 is f. A comparator 80 outputs a logic "1" signal to the paddy when the signal detected by the detector 74 has a level equal to or higher than the threshold Th1, and a comparator 80 outputs a logic "1" signal to the rice grains when the output level of the band pass filter 75 is equal to or higher than the threshold Th2. Next, a comparator 82 which outputs a logic 1° signal is an anchor. When a signal of logic "1°" is output from the antenna 82, it can be determined that the magnetic tape 18 is digitally recorded.

(Hereinafter, blank space) [Effects of the Invention] As explained above, the present invention provides an image that can correctly determine in which recording format an image information signal recorded on a recording medium is recorded. A signal reproducing device can be provided.

(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 during 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 (8) to (D) are implementations shown in Figure 1. A diagram showing a video track formed by example, FIG. 7 is 180
Figure 8 is a block diagram for distinguishing between analog and digital based on the presence or absence of color burst, Figure 9 is a block diagram for discriminating analog and digital based on the presence or absence of a horizontal synchronization signal. , Fig. 10 is a block diagram for distinguishing between analog and digital based on the presence or absence of a triangle or synchronization pulse, Fig. 11 is a block diagram for discriminating analog and digital based on the size of the error rate, and Fig. 12 is a block diagram for discriminating between analog and digital based on the presence or absence of a triangle or synchronization pulse. Fig. 13 is a spectrum diagram showing the relationship between the pilot signal and the video signal, and Fig. 14 is a diagram showing the pilot signal f. 4.../D converter, 6... Digital signal processing circuit for recording, 8... Switching/
Distributor, 12... Rotating head cylinder, 168, 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.

Claims (1)

[Claims] 1) An image information signal is recorded on a recording medium in which the image information signal is recorded in the form of a digital image information signal containing a predetermined pulse signal or in the form of an analog image information signal not containing a predetermined pulse signal. A reproducing device, comprising: reproducing means for reproducing an image information signal recorded on a recording medium; and whether or not a predetermined pulse signal is included in the image information signal reproduced from the recording medium by the reproducing means. 1. An image reproducing device comprising an analog/digital discriminating means for discriminating a digital discriminating signal and outputting a digital discriminating signal when a predetermined pulse signal is included.