JPS63298862A - Recording/reproducing device - Google Patents

Abstract

PURPOSE:To ensure the recording or reproduction of an analog and a digital picture information signal by sharing a recording or reproducing head for analog picture information signal for a recording or reproducing head of a digital picture information signal. CONSTITUTION:Heads H-1-H-5 arranged at an interval of 90 deg. in a rotary head cylinder 12 have an azimuth angle. The heads H-4, H-2 are inverse azimuth heads opposed by 180 deg. to each other and are used to record/reproduce a conventional analog signal or to record/reproduce a digital signal as a mode. Thus, the recording or reproducing device is obtained, which can record the analog or digital picture information signal onto the recording medium or reproduce the analog or digital picture information signal recorded on the recording medium.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to recording an image information signal on a recording medium,
The present invention relates to a recording or reproducing device that reproduces an image information signal from a recording medium on which the image information signal is recorded.

[Prior Art] Currently known analog VTRs (video tape recorders) include 172
Inch home VTRs are widely known. Other VTs
A commercial 1-inch VTR is used as R.
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 where home-use 1/2-inch VTRs have become extremely popular, it is expected that not only digital VTRs but also analogue The coexistence of a log VTR 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.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a recording or reproducing apparatus capable of recording an analog or digital image information signal on a recording medium and reproducing an analog or digital image information signal recorded on a recording medium. It's about doing.

(Hereinafter, blank space) [Means for solving the problem j The recording or reproducing device according to the present invention records an image information signal on a recording medium, and records an image from a recording medium on which the image information signal is recorded. A device for reproducing an information signal, which records a digital image information signal on the recording medium or reproduces a digital image information signal from a recording medium on which the digital image information signal is recorded. The first head for and the said #! A second head for recording an analog or digital image information signal on the medium or reproducing the analog or digital image information signal from a recording medium on which the analog or digital image information signal is recorded. It is something that

(Hereinafter, blank space) [Function] According to the above-described configuration, the present invention uses a common head for recording or reproducing analog image information signals and a head for recording or reproducing digital image information signals, thereby reducing the need for increased hardware. It is possible to reliably record or reproduce analog and digital image information signals without causing problems. - (Hereinafter, blank space) [Examples] The present invention will be described in detail below based on Examples.

Figure 1 shows an analog/digital compatible V that can be used with the present invention.
FIG. 2 is a block diagram showing an example of a TR.

In this figure, 2 is an analog video signal input terminal, SWI is a changeover switch for selecting analog recording mode or digital recording mode, 4 is an analog-to-digital (^10) converter, 6 is a recording digital signal processing circuit, and 7 is a recording digital signal processing circuit. A recording analog signal processing circuit, 8 a signal switch/distributor, 10A to IOE amplifiers, and 12 a rotary head cylinder.

H-1 to H-5 are video heads arranged at intervals of 909, and each head has an azimuth angle as shown. Of these video heads, H-4 and H-2 are 1
It is a reverse azimuth head that faces 80 degrees, and is used when recording/reproducing a normal analog signal or as an aspect of recording/reproducing a digital signal (details will be explained later regarding Fig. 6 (B)). used for

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 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 high-power 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 in digital mode. In this diagram,
The configurations of the digital signal processing circuits 6 and 22 are shown in more detail.

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

During recording, an input 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 NTS method, a sampling rate of three times (3fsc) or four times (4fsc) the color subcarrier frequency (fsc) is set, and the quantization level is Preferably, 7 or 8 bits are selected.

The digital data obtained in this way is approximately 10QMb
ps data rate, so for example V
The information band is too wide to be recorded on a cassette tape such as IIS. Therefore, the data amount is reduced to about one-fourth using the band compressor 6A. 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 [lPCM (differential PC
7 bits of information per sample is compressed to 4 bits by M 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, 15li 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 countermeasure against transmission errors and dropouts caused by magnetic recording/reproduction, and also adds block rD 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.). 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 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 DPCM-encoded difference data (4 bits → 7 bits), 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

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 described above, it is assumed that the analog/digital discrimination circuit 28 has previously determined that a digital signal is 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
6A 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, 28
C is a delay line for time-aligning the color signal. The other blocks 260 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 (767kll) filter.
□→3.58 MHz), and 26F is a band pass filter (BPF) for removing unnecessary frequency components caused by 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 to each other) mounted oppositely on the rotary head cylinder 12 The signals obtained from the azimuth angle) are respectively input to the amplifier 1
It is supplied to a high-pass filter 26^ and a low-pass filter 26D via 9B and 19[1. 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, video heads H-2 and H-4 described in connection with FIG.
and amplifiers 198 and 190 are used, 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.
．． Digital processing is performed using a D/A converter 24. That is, in this embodiment, instead of using a separate circuit as an A/D converter, the A/D converter 4 (see Fig. 1) already installed in the recording side circuit is used for recording digital signals. 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 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 (single-split display), it is also possible to share the ^/D converter and the like required for a digital VTR, so there is no increase in manufacturing costs.

FIGS. 6A to 6D are diagrams illustrating the relationship between the rotation speeds of the rotary head cylinder 12 and capstan 17 and recording/reproduction track patterns. Numbers "1" to "5" in the track pattern shown on the right side of the figure indicate that video heads (1-1 to H-5) are currently located at the positions shown, respectively. Furthermore, the shaded portion in the track indicates that tracing has already been completed.

FIG. 6(A) is an explanatory diagram of operations for recording/reproducing analog signals. Here, the rotating head cylinder is
800 rpm (standard speed: x1) and rotate the capstan at standard speed (XI). 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 capstan are controlled by a system controller 34 (see FIG. 1).

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). Further, the recording/reproducing mode shown in this figure is the longest time mode when recording/reproducing in digital mode. The video heads used are reverse azimuth heads H-2 and H-4, which are 180° opposed and used during analog recording/reproduction.

FIG. 6(C) shows the operation mode when recording/reproducing digital signals using four video heads H-4, H-5, 11-1, and H-3 arranged 90 degrees apart. FIG. In this aspect, the system controller 34 sets the rotary head cylinder to standard speed (x1) and the capstan 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. 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 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)"
” are heads H-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,
Encoding in band compressor 6A and band expander 22A
It is necessary to appropriately change the contents of the restoration process (number of quantization levels, bit rate, etc.).

Furthermore, the widths of the tracks shown in FIGS. 6(8) to 6(D) are all the same. In other words, in this embodiment, the head H-
1-) The physical shape of I-5 is uniform and can be applied to both analog and digital systems.

For Figures 6(A) to (D), move the video head to 9
Although the explanation has been made using a four-head type arranged at 0° intervals, various tracks can also be formed by rotating two heads facing each other 180° 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(A) 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, whereas when recording analog, color burst signals are included, so there is a difference in the level of the low-frequency components. occurs. Therefore, in order to detect such a level difference, the configuration shown in this figure is adopted.

In FIG. 8, reference numeral 42 inputs the RF input signal obtained through the video head, and passes through a band pass filter (BPF) that passes a predetermined low frequency signal (700kHz or less) centered on the carrier frequency of the low frequency conversion 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 HIyne 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
54 is a l/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. be.

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. 1θ, 58 is a preamplifier that manually 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 62A, 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 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 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, the count value of the counter 70 becomes N(L, .
When the value is greater than the threshold (threshold), it is determined that analog recording is being performed, and in other cases, 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, to f4 of a predetermined frequency 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, "°
Signal indicating that digital recording is being performed ° “f,”
Record in advance. The frequency spectrum at this time is
The result is as shown in Fig. 13. In addition, when performing DTP (dynamic track following) control to move the video head to follow the track using the four types of pilot signals fINf4, a conventionally known method can be used, so we will explain it below. omitted.

FIG. 14 is a circuit diagram for detecting the pilot signal f0 and determining analog recording/digital recording. In this figure, 74 is f for detecting the presence or absence of pilot signal f0. A detector, 76 is a band pass filter that passes signals near the clock frequency, and 78 is a comparator that outputs a logic "1" signal when the signal detected by the f0 detector 74 has a level equal to or higher than the threshold Th1. vessel, 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.

(Hereinafter, blank space) [Effects of the Invention] As explained above, the present invention enables recording of analog or digital image information signals on a recording medium, and recording of analog or digital image information signals recorded on a recording medium. It is possible to provide a recording or reproducing device capable of reproducing.

(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 (8) 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 1O is a block diagram for distinguishing between analog and digital based on the presence or absence of a triangle 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 a block diagram for performing analog/digital discrimination based on the presence or absence of the pilot signal fo. 4...A/D converter, 6...Digital signal processing circuit for recording, 8...Switching/
Distributor, 12... Rotating head cylinder, 11iA, 16B... Rope 4 ring post, 18...
...Magnetic tape, 20...Switcher/coupler, 22...Digital signal processing circuit for reproduction, 24...D
/^ 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. Figure 7≧:＼〈Mouse Figure 12

Claims (1)

[Claims] 1) An apparatus for recording an image information signal on a recording medium or reproducing an image information signal from a recording medium on which the image information signal is recorded, the apparatus comprising: a first head for recording a digital image information signal or reproducing a digital image information signal from a recording medium on which the digital image information signal is recorded; and a second head for recording an image information signal or reproducing an analog or digital image information signal from a recording medium on which the analog or digital image information signal is recorded. playback device.