JPH0344282A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To generate a video signal with correct segment arrangement by identifying a segment from a reproduced control signal at vari-speed reproduction and controlling write and readout of a reproduced video signal based on the identification. CONSTITUTION:The above device consists of a control signal recording means 27 recording a control signal (a) of one frame or one field period onto a magnetic tape, segment identification means 23, 24 identifying each segment from a control signal (b) reproduced at a vari-speed reproduction, a means 25 generating a segment switching signal (d) through the detection of a reproduced video signal or a head switching signal (e) and a memory control means 26 controlling write and readout of a memory with a segment identification (c) and the segment switching signal (d) to generate a video signal of a prescribed segment arrangement. Thus, the video signal with correct segment arrangement is read out of the memory.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to high-definition video tape recorders (hereinafter referred to as VTRs) that record and reproduce wideband signals such as high-definition signals. The present invention relates to a magnetic recording and reproducing apparatus such as a helical scan type VTR that divides a video signal of one field or one frame into an integer number of two or more segments and records them.

[Prior Art] FIG. 11 is a perspective view showing the structure of a rotating head section of a conventional two-head helical scan type VTR, and FIG. 12 is a plan view thereof. In the figure, (1) is a magnetic tape that runs in the direction of arrow X. (2) is the capstan, (
4) is a rotating drum that rotates in the direction of the arrow y.

(3a) is the video head for video track A, (3b
) is a video head for video track B, and these video heads (3a) and (3b) are connected to the rotating drum (4).
) are mounted at a rotational phase angle of 180' and have the same azimuth angle. (5) is an audio head,
(8) is a control head.

FIG. 13 shows the recording pattern on the tape (1), in which (7) is an audio track, (8) is a video track, and consists of 82 tracks. (9)
is the control track.

In the helical scan VTR configured as described above, the segment division recording method is known as a method for recording wideband signals such as high-definition signals without changing the diameter of the rotating drum 0).

That is, in the VTRs having the configurations shown in FIGS. 11 and 12, the number of rotations of the rotating drum (0) is changed to double or triple, and the running speed of the tape (1) is also doubled or tripled depending on the number of drum rotations.
This is a segment division recording method in which the data is recorded in multiples. With this segmented recording method, the relative speed between the tape and video head can be increased, and the recording wavelength can also be lengthened, making it possible to record broadband signals even with current magnetic recording technology. .

FIG. 14 shows a tape pattern recorded with the rotational speed of the rotating drum 0) tripled as described above.

The first field consists of A1, A2, and A3, the second field consists of B1-B2, and B3, and the signal of frame ■ is recorded on six tracks.
Subscripts 1, 2, 3, . . . before B3 are signals of the first, second, third, . . . frames, respectively.

Next, a case will be described in which a tape recorded by dividing it into three segments as described above is reproduced by changing the feed speed to an integral multiple of the normal speed.

FIG. 15 is a block circuit diagram showing the configuration of a variable speed reproduction system of a conventional helical scan type VTR. In the same figure, (10a) and (lob) are video heads (3a)
, a head amplifier that amplifies the output of (3b), (11
) is a head changeover switch that switches the output of the video heads (3a) and (3b), and (12) is an input terminal for a head changeover signal that controls switching of the video head head changeover switch (11).

(13) is an FM demodulation circuit that performs FM demodulation of the reproduced signal.

(!4) is the reproduced video signal tA/
An A/D converter that performs D conversion, (15) a switch that switches the signal path depending on normal playback and variable speed playback, (16)
is a memory that stores playback signals during variable speed playback, (17)
is a reproduction signal processing circuit that performs various signal processing on the reproduction signal;
(18) is a D/A converter that performs D/A conversion of the output of the reproduced signal processing circuit (17), and (13) is an output terminal that outputs the reproduced video signal.

(20) is an envelope detection circuit that detects the envelope of the output of the video heads (3a) and (3b);
1) is a comparator that compares the output of the envelope detection circuit (20) with a reference voltage, and (22) is a memory control circuit that controls the memory (16) using the output of the comparator (21) and a head switching signal.

Next, the operation of the variable speed reproducing system will be explained.

When a tape recorded using the divided segment method as shown in Figure 14 is played back at four times the recording speed, the video head (
3a) and (3b) scan along the trajectory shown by the broken line in FIG. 16, so the video head (3a).

The reproduced video signal in (3b) is as shown in FIG.

This signal is FM demodulated by the FM demodulation circuit (13), and the A/D
Converter (10 performs A/D conversion.

On the other hand, the reproduced video signal is input to an envelope detection circuit (20) and subjected to envelope detection, and this detection signal is compared with a reference voltage in a comparator (21) to detect each segment switching period and output a segment switching signal.

Next, the memory control circuit (22) generates a write address from the segment switching signal and head switching signal, and according to this write address, the output of the A/D converter (14) during variable speed playback is transferred to the memory (1B). will be written to.

[Problems to be Solved by the Invention] Since the conventional magnetic recording/reproducing device is configured as described above, when variable speed playback is performed from a segment-divided recording type tape, each segment of the reproduced video signal cannot be identified. However, there is a problem in that the positional relationship of each segment is distorted during playback, and therefore a good playback image cannot be obtained when displayed on a screen.

This invention was made in order to solve the above-mentioned problems, and it uses a magnetic material that can correctly arrange each segment and obtain a good reproduced image when performing variable speed playback from a segment-divided recording tape. The purpose is to provide a recording/playback device.

[Means for Solving the Problems] The magnetic recording and reproducing apparatus according to the present invention uses a segment division recording method in which a video signal of one field or one frame is divided into an integer number of two or more segments and recorded. A control signal recording means for recording a control signal of one field period on a magnetic tape, a segment identification means for identifying each segment from the control signal reproduced during variable speed reproduction, and a segment identification means for identifying each segment by detecting a head switching signal or a reproduced video signal The present invention is characterized by comprising means for generating a switching signal, and memory control means for controlling writing to and reading from memory using the segment identification signal and segment switching signal to create a video signal of a predetermined segment arrangement.

[Function] According to the present invention, while the control signal is recorded at l-frame or l-field cycles, during variable speed playback,
Identify each segment from the playback control signal, switch segments from the video signal played at variable speed and the control signal, and read the video signal with the correct segment arrangement from the memory by controlling writing to and reading from the memory. be able to.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block circuit diagram showing the configuration of a reproduction system of a helical scan VTR according to an embodiment of the present invention.
In the same figure, (1) and (3a).

(3b), (10a), and (10b) to (21) are the same as the conventional example shown in FIG. 15, so the same reference numerals are given and the explanation thereof will be omitted.

In Figure 1, (23) is the control head, (2
0 is a playback control amplifier that amplifies the playback control signal (b), (25) is the playback control signal (b)
Segment identification signal generating means (2B) generates a signal for identifying each segment by shaping the pulses of
), and the output (C) of the segment identification signal generating means (25)
) is a memory control circuit that controls the memory (18).

(27) is a control signal recording means for recording the cycle of the control signal as one frame or one field, and (28) is a recording control amplifier that amplifies the recording control signal (b).

Next, the operation of the above configuration will be explained. Note that a case where the number of segment divisions is three will be explained.

During recording, the control signal (a) is as shown in Figure 2 (A
), one field is recorded as one period. During reproduction, this control signal becomes a reproduction control signal (b) as shown in FIG. 2(B). However, only the positive pulse of the reproduction control signal (b) is used to control the tape running system.

During variable speed playback at four times the normal playback speed, the playback video signal (V) is as shown in Figure 3 (A), and the playback control signal (b) is as shown in Figure 3 (B). Become.

Next, the reproduction control signal (b) is shaped by the segment identification signal generating means (25), and its negative pulse (
-b) is removed and the positive pulse (+b) is applied to Figure 3 (C
) A segment identification signal (c) as shown in FIG.

Further, the envelope detection circuit (20) and the comparator (21) convert the segment switching signal (d) as shown in FIG. 3(D) from the reproduced video signal (V), as in the conventional example.
occurs. Next, the memory control circuit (28
), the loading of 1 into the memory (1B) is controlled by a segment identification signal (C), a segment switching signal (d), and a head switching signal (e) as shown in FIG. 3(E).

FIG. 4 is a block circuit diagram showing an example of the structure of the memory control circuit (26) and memory (18).

In the figure, (28) is an input terminal for the segment identification signal (c), (29) is an input terminal for the head switching signal (e), and (30) is an input terminal for the segment switching signal (d).

(31) is segment number determining means for determining a segment number from the segment identification signal (C) and head switching signal (e); (32) is for selecting a memory according to the segment designated by segment number determining means (31); Write memory selection means.

(33) is address reset signal generation means for generating a signal for resetting write and read addresses;
4) is an address generation means for generating write and read addresses, and (35) is a read memory selection means for selecting a memory at the time of reading.

(3B) is an input terminal for variable speed playback video signal (V), (37
), (38), (39) are the first . Second. Memory for third segment, 00
) is the output terminal.

Next, the operation of the configuration shown in FIG. 4 will be explained.

Figure 5 (A) shows the track pattern and the trajectory of the head during variable speed playback, Figure 5 (B) shows the recorded control signal (a), and Figure 5 (C) shows the head switching signal (
e) and (D) of the same figure show the playback control signal (b) during variable speed playback, and the segment identification signal (C) shown in the same figure (E) is the playback control signal (b).
It is created by removing the negative pulse (-b) of and using only the positive pulse (+b). Here, as shown in FIG. 5(E), the segment identification signal (c) and head switching signal (e) in which the positional relationship is the same during normal playback is defined as (C1), (C2), (C2). ), (C3).

The symbol (C4)... is attached.

For example, during variable speed playback at 4x speed, each segment identification signal (C2), (C3), (C4)... has a different positional relationship with respect to the head switching signal (e), and when switching the head As shown in Figure 5 (F), the first segment is (C2) the second segment) (82), (C3) (7) the third segment (A3), (C4) is the first segment (AI
), (C8), the second segment (B2), etc. In this way, the position where each segment identification signal is at H level and the head switching signal (
From the relationship with e), the first segment number at the time of the next head switching can be determined.

Segment number determination method (
31) is the l head scanning period, that is, the video head (
The period during which tape (1) is scanned by 3a) and (3b) is divided into three areas from ■ to @ as shown in Fig. 6(A), and each area is divided into three areas as shown in Fig. 6(B). A signal (fa
), (fb), and (fc).

Next, the segment identification signal (C) shown in FIG. 6(C)
The position at which the signal is at H level is determined from the signals (fa), (fb), and (fc) indicating the above-mentioned regions ① to ＠.

The segment number of the first segment of the head scanning period of the next session corresponding to the obtained area is determined from the correspondence as shown in FIG. 7, and the segment number is sent to the write memory selection means (32).

This write memory selection means (32) selects the segment number determined as described above from the beginning of the next head scanning period in accordance with the segment switching signal (tl) and the head switching signal (e) in FIGS. As shown in D), the segment number (g) is switched in the order of 1 → 2 → 3 → 1 moan 2 .

Next, the segment number (g) created as above
As shown in FIGS. 8(E) to (G), the first,
Memory write enable signal (hl) for second and third segments
, (A2), and (A3) are created.

On the other hand, the address reset signal generating means (33)
As shown in Figure (H), an address reset signal (i) is created in response to the head switching signal (e).

In response to this address reset signal (i), the address generating means (30) resets the address and generates an address (j) that increases by one in accordance with the clock, as shown in FIG. 8 (1).

As mentioned above, the video signal during 4x variable speed playback is the 9th (
This reproduced video signal (V) as shown in A) is shown in Fig. 9 (
Based on the address (j) and each segment write enable signal (hl), (h2), (h3) shown in B) to (E), each segment memory (37), (38)
, (38) as reproduced video signals as shown in FIGS. 9(F), (G), and (H).

Further, in order to obtain a good reproduced image when reading out from the memory (16), a readout memory selection means (35) is provided.
Each time t* head is switched, each segment memory (37), (38), (3
9), create memory read enable signals (kl), (kl), and (k3) for the first, second, and third segments as shown in Figure 1O (A) to (C). .

These readable signals for each segment (kl) ~ (
kl) and the memory for each segment (37), (38) based on the address (D) shown in Figure 10 CD).
, (39) to create one field of reproduced video signal (V) as shown in FIG. 3(E).

Although this video signal (V) contains video signals for one frame before and after, it is possible to obtain a good reproduced image since the video signal (V) has a large correlation between frames.

In the above embodiment, the case of variable speed playback of 4 times speed has been explained, but if the speed number is larger than 1, the memory control circuit (2B
), the same effects as in the above embodiment can be achieved.

Also, even when the variable playback speed is l/n times the speed, the first
In the configuration example shown in the figure, by determining the segment number using the playback control signal and controlling the memories (37), (38), and (38) for each segment, as in the case of the above embodiment, a good A reproduced image can be obtained.

Furthermore, even when the cycle of the control signal (a) is recorded as one frame, a segment identification signal (C) is created from the positive pulse (+b) of the reproduction control signal (b) in the same manner as in the above embodiment, and the segment identification signal (C) is identified. A good reproduced image can be obtained by controlling the writing and reading of the memory (1B) based on the signal (c) and rearranging the video signals during variable speed reproduction. Further, even if the segment identification signal (C) is created from the positive and negative pulses of the reproduction control signal (b), the same effect as in the above embodiment can be obtained.

Also, the segment identification signal (c) during the l head scanning period.
To find the position of the segment identification signal (C), start counting every time the head scan is switched, find the count value at which the segment identification signal (C) goes to H level, and determine the position of the segment identification signal (C) based on that count value. Good too.

In addition, by creating a sawtooth wave whose voltage becomes 0 when the head scan is switched and increases until the next head scan switch, the position of the segment identification signal (c) is determined from the sawtooth wave voltage at the position of the segment identification signal (c). You can ask for it.

Also, the number of segment divisions is not limited to three, and
Even if the video signal is divided into a plurality of channels and into a plurality of segments, a good reproduced image can be obtained in the same manner as in the above embodiment.

Also, instead of the segment switching signal created from the envelope test wave circuit (20) and the comparator (21) shown in FIG. 1, a signal is created to switch the segment according to the variable playback speed during one head scanning period. Good too.

In addition, when configuring the memory to be controlled by creating a segment switching signal from the playback envelope and a signal that prevents writing to the memory when the envelope is below a certain level, that is, a write inhibit signal. , a reproduced image with a good S/N ratio and few noise bars can be obtained.

[Effects of the Invention] As described above, according to the present invention, a control signal is recorded in one field or one frame period, a segment is identified from the playback control signal during variable speed playback, and the segment is stored in the memory based on the segment. By controlling the writing and reading of the reproduced video signal, it is possible to create a video signal with the correct segment arrangement, so it is possible to obtain a good reproduced image even during variable speed reproduction using the segment division recording function. .

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing the configuration of a playback system of a helical scan VTR according to an embodiment of the present invention, FIG. 2 is a waveform diagram of recording and playback control signals in this embodiment, and FIG. 3 is a waveform diagram of this embodiment. 4 is a block circuit diagram showing the bottom side of the memory control circuit and the memory, and FIG. 5 is a diagram for explaining the relationship between the segment identification signal and the segment number. , FIG. 6 is a diagram for explaining the operation of the segment number determining means in the configuration example of FIG. 4, FIG. 7 is a chart showing an example of the correspondence between the segment identification signal and the segment number, and FIGS. 8 and 9. 10 is a signal waveform diagram of each part for explaining the operation of the memory control circuit and memory, and FIGS. 11 and 12 are perspective views showing the configuration of a rotary head of a rotary two-head type helical scan type VTR. A plan view, FIG. 13 is a diagram showing a conventional tape pattern, FIG. 14 is a diagram showing a tape pattern during segment division recording, FIG. 15 is a block circuit diagram showing the configuration of a variable speed playback system of a conventional VTR, FIG. 16 is a diagram showing the trajectory of the head during variable speed reproduction of a tape recorded by the segment method, and FIG. 17 is a diagram showing the reproduced video signal at that time. (IB)...Memory, (20)...Envelope detection circuit, (21)...Comparator, (2fl)...
. . . Memory control circuit, (25) . . . Segment identification signal generation means, (27) . . . Control signal recording means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) Convert 1 field or 1 frame of video signal into 2
In a magnetic recording/reproducing device configured to divide into an integral number of segments or more and record on an integral number of tracks of 2 or more, a control signal with a cycle that is an integral multiple of one frame or one field is recorded on a magnetic tape. a control signal recording means; a segment identification means for identifying each segment from the control signal reproduced at variable speed;
segment switching signal generation means for generating a segment switching signal by detecting a head switching signal for controlling switching of the magnetic head or a reproduced video signal; 1. A magnetic recording and reproducing device comprising: memory control means for controlling writing and reading to create a video signal with a predetermined segment arrangement.