JPS63234449A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To improve the convenience of use for a user by muting a video signal at the time of search when a device is so controlled that the video signal of a prescribed frame is reproduced. CONSTITUTION:At the time of search, a command signal CMD to mute the video signal and the audio signal of a VTR 100 is supplied from a CPU 51 of a microcomputer 200 to a microcomputer 46 of the VTR 100, and muting circuits 45, 73, and 74 of the video signal system and the audio signal system are controlled by the microcomputer 46 not to output a video signal SV and audio signals SL and SR to output terminals 44, 77, and 78. Since the video signal and audio signals are muted in this manner at the time of search, pictures of the frames preceding a prescribed frame to be searched are not displayed to improve the convenience of use.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention provides a method for superimposing a frame code on a video signal.
The present invention relates to a magnetic reproducing device for reproducing video signals from a magnetic tape recorded on a JL diagonal trunk.

[Summary of the invention]

The present invention provides a magnetic reproducing apparatus that reproduces video signals from a magnetic tape in which a frame code is superimposed on a video signal and is recorded on an inclined track. This is intended to improve usability for the user by allowing minting to occur.

(Prior Art) Conventionally, in a video tape recorder (VTR) that records and reproduces a video signal on an inclined track of a magnetic tape, a video tape recorder (VTR) that records and reproduces a video signal by superimposing a frame code has been proposed.Such a VTR can be provided with a search function that controls the reproduction of a predetermined frame of the video signal based on the frame code obtained from the reproduced video signal.

[Problem that the invention seeks to solve]

In providing such a search function, if both sides were to be displayed during the search, the following problems would occur when used as a videoless bonder, for example.

Assume that the contents and order of information are recorded on the magnetic tape as shown in FIG.

In this case, (1) First, the problem part (for example, frames 1 to 4) is played back and the problem is displayed on the screen.

(2) Next, the answer part (for example, 5 frames) is played back, the answer is displayed on the screen, and the answerer is asked to select the correct answer number using a keyboard or the like.

0-1 Next, when the answer is correct, the correct part (for example, 6 frames) is played back and the correct answer is displayed on the screen, and then the question part (for example, from 7 frames onward) is played back. The problem will be displayed on the screen.

0-2 Also, if the answer is incorrect, the incorrect part common to each question (e.g. 52 frames) will be played back and the incorrect answer will be displayed on the screen, followed by the selected part (e.g. 53 frames). frame) is played and a selection screen is displayed, allowing the respondent to choose whether to try the same question again or the next question.

Thereafter, the above-mentioned steps ◎ to ◎ are repeatedly executed.

Here, when executing ■-2 above, the frames in the middle are skipped in search mode from the answer part (5 frames) to the incorrect/correct answer part (52 frames), and the correct answer part (6 frames) The correct answer screen will be displayed and there is a risk that the answerer will be able to see it. Also, even if it is not visible at this time, the problem part (
1 frame), a correct answer screen based on the intermediate correct answer part (6 frames) will be displayed, and there is a risk that the answerer will be able to see it.

Therefore, there is an inconvenience that the educational effect of the videoless bonder is reduced.

In view of the above, the present invention aims to improve usability for users.

[Means for solving problems]

The present invention is directed to a magnetic tape T in which a frame code FC is superimposed on a video signal and recorded on inclined tracks TA and TB.
This is a magnetic reproducing device for reproducing video signals, and the video signals are muted during a search.

[Effect]

In the above configuration, since the video signal is muted during a search to control the reproduction of the video signal of a predetermined frame, it is possible to prevent the screen of frames halfway up to the predetermined frame from being displayed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In the figure, (100) is a rotating two-head helical scan type video tape recorder (VTR). VT
At R(100), HA and HB are 180° to each other
The magnetic head is a rotating magnetic head arranged at an angular interval of 1, and rotates once every two fields (one frame). Further, T is a magnetic tape, which is wound diagonally around the circumferential surface of the tape guide drum (1) by more than 180° during recording and reproduction, and runs at a predetermined speed.

As shown in FIG. 2, the magnetic tape T has one inclined recording rack TA and TB on which video signals are recorded. The video signal includes, for example, the 17th field of the first field and the second field that constitute each frame as shown in FIG.
A frame code FC is superimposed on the 18th horizontal period. This frame code FC is, for example, a 24-bit B code in which each digit of a 6-digit decimal number is expressed as a 4-bit binary number.
CD code, its high level “1” and low level “
O” is the white level of the luminance signal (for example, 80I
RE) and the pedestal level. In this case, the video signal is a carrier color signal C that has been low-pass converted.
It is recorded in the form of a composite signal of L and an FM-modulated luminance signal YFM.

Figure 4 shows an example of the frequency spectrum.
The luminance signal Y is FM modulated so that the leading edge of the synchronization signal is 3.8 MHz and the white peak is 5.4 MHz. In addition, the color subcarrier frequency is 3.58MHz (NTSC
The carrier color signal C of the method) has a color subcarrier frequency of 688k.
)Iz.

In addition, as shown in FIG. 2, there are two recording tracks TA and TH in the longitudinal direction of the magnetic tape T, that is, one recording track per frame.
A recorded control track TC and audio tracks TL and TR on which left and right audio signals are recorded are formed.

Figure 5 shows the mechanical parts of the VTR (100), where (1) is the tape guide drum mentioned above, (2) is the capstan, (3) is the moving pinch roller, and (4) is the audio signal eraser. Magnetic head, (5) is control pulse CTL
These are a magnetic head for recording and reproducing (5C) and a magnetic head for recording and reproducing audio signals (SL) and (5R).

(6) to (13) are tape guides, among which (?),
(8).

(11), (12) and (13) are moving tape guides, and the others are fixed tape guides. Also, (15)
is the tape cassette, (16) is its supply reel, (1
7) is a take-up reel.

Further, (20) is a magnetic head for reproducing the control pulse CTL, which is also used as an erasing magnetic head for erasing the entire width of the magnetic tape T.

In such a mechanism, during recording and reproduction, the magnetic tape T is pulled out from the tape cassette (15), and the tape winding means (21) consisting of a moving tape guide etc.
(16) → (6) → (20) → (7) → (11 → (4)
→(5)→(2)→(13)→(12)→(11)→(
The magnetic tape is wound around the tape guide drum (1) and runs through the first magnetic tape running path of 8)→(9)→(10)-(17). In this case, during reproduction, the control pulse CTL is sent from the magnetic head (5C).
is obtained by being regenerated.

Also, during fast forwarding and rewinding, the tape winding means (2
1), the winding angle of the magnetic tape T with respect to the tape guide drum (1) is greatly reduced or it is not wound at all, and the magnetic tape T is wound around the tape cassette (15).
The magnetic tape T is (16) → (6) → (20) →
The magnetic tape is configured to run along a second magnetic tape running path of (7)→(8)→(9)→(10)→(17). In this case, the control pulse CTL is obtained by being reproduced from the magnetic head (20).

Returning to FIG. 1, when the heads HA and HB sequentially scan the recording tracks on the magnetic tape T during reproduction, the reproduction signals obtained from the heads HA and HB are transmitted to the reproduction amplifier (
The switch circuit (31A) and (31B)
2) is supplied to the A side and B side fixed terminals. This switch circuit (32) is supplied with an RF switching pulse PRF from a terminal (33), and is switched to the A side and the B side during one field period when the heads HA and HB scan the magnetic tape T, respectively.

The output signal of the switch circuit (32) is supplied to a bi-pulse filter (34) to extract an FM luminance signal YFM, and this FM luminance signal YFM is supplied to an FM reconverter 36) via a limiter (35). Then, the luminance signal Y is demodulated. This luminance signal Y is supplied to a synthesizer (38) via a low-pass filter (37).

Further, the output signal of the switch circuit (32) is supplied to a low-pass filter (39) to extract a low-pass converted color signal CL, and this low-pass converted color signal cL is sent to an ACC circuit (40).
The signal is supplied to the frequency conversion circuit (41) via the carrier color signal C and the color subcarrier frequency is 3.58M)Iz. - This carrier color signal C is supplied to the synthesizer (3B) via a bandpass filter (42).

A video signal SV in which the luminance signal Y and the carrier color signal C are combined is obtained from the synthesizer (38), and this video signal SV is passed through the miniting circuit (45) and the output amplifier (4).
3) to the video output terminal (44).

Also, when the magnetic heads (5L) and (5R) scan the audio tracks TL and TR during reproduction, the audio signal SL obtained from these magnetic heads (5L) and (5R)
and SR respectively include reproduction amplifiers (71) and (72), muting circuits (73) and (74), and output amplifiers (
The signals are led out to audio output terminals (77) and (78) via terminals 75) and (76).

Note that in the VTR (100), the video signal recording system and the audio signal recording system are omitted for simplicity of drawing.

Further, (46) is a microcomputer (hereinafter referred to as microcomputer) provided in the VTR (100), and the VT
It controls the operation of R(100).

(200”) is the microcontroller (
This is a microcomputer for supplying command signals to 46). In the microcomputer (200), (51) is the CPU, (
52) is a ROM, and (53) is a RAM.

Further, a controller (300) operated by a user is connected to the CPU via an input/output interface (54).

Further, the CPU (51) generates a command signal CMD according to the user's operation of the controller (300), and this command signal CMD is sent to the microcomputer (46) of the VTR (100) via the input/output interface (55).
As mentioned above, the operation of the VTR (100) is controlled by the microcomputer (46) based on this command signal CMD.
controlled by

Furthermore, the luminance signal Y from the low-pass filter (37) is supplied to the comparator (62) via the amplifier (61). This comparator (62) has a white level (e.g. 801R).
A reference voltage VREF corresponding to an intermediate level between E) and the pedestal level is supplied, and the luminance signal Y is based on this reference voltage V
It is compared with REF. Then, the luminance signal Y is the reference voltage V
When the level is greater and less than REF, the comparator (
62) respectively output high level "1" and low level "0" signals.

Therefore, when the frame code FC is superimposed on the luminance signal Y, the 17th and 18th horizontal periods of the first and second fields constituting each frame are higher than the high level "1" and the low level "O". A frame code FC is output.

The output signal of this comparator (62) is supplied to a decoder (63), in which the frame code FC
is extracted, and the 24-biat BCD code is converted into, for example, a binary code. This decoder (63
) is supplied to the CPU (51) via an input/output interface (56).

Also, although not mentioned above, the output signals of the VTR (100) (Magnetic head (5C) and (20)
) is supplied to the fixed terminals on the A side and B side.

This switch circuit (49) is supplied with a switching control signal from a microcomputer (46), and is connected to the A side during playback, and is connected to the B side during fast forwarding and rewinding. During playback, as described above, the magnetic tape T is set on the first magnetic tape running path (shown by the solid line in FIG. 5), and the magnetic tape T is
Since the control pulse CTL is obtained by being reproduced from C), this control pulse CTL is output from the switch circuit (49). On the other hand, during fast forwarding and rewinding, as described above, the magnetic tape T is set on the second magnetic tape running path (shown by the broken line in FIG. 5), and the magnetic head (20
), the control pulse CTL is output from the switch circuit (49). The control pulse CTL from the switch circuit (49) is supplied as a clock to the counter (57) of the microcomputer (200).

Further, when the search mode is selected by the i action of the user's controller (300), when the frame code FC is supplied from the decoder (63) to the CP'tJ (51), the CPU (51) selects this frame code FC. The frame indicated by is written into the buffer section of the RAM (53) as the current frame. Then, each time the frame code FC is supplied to the CPU (51), the RAM (
The contents of the buffer section 53) are sequentially updated. In addition, in this search mode, the counter (5
The count value 7) is supplied to the CPU (51), and a frame is calculated and predicted from the change in the count value and the frame written in the buffer section of the RAM (53).

Then, when the frame code FC is not supplied, the CPU (51) writes this predicted frame into the buffer section of the RAM (53) as the current frame.

For example, frame code FC is not supplied at all in fast forward mode or rewind mode, and in high-speed playback mode, the heads HA and HB cross recording tracks TA and TB diagonally, so frame code FC is supplied only every predetermined frame. Not done.

Further, in this search mode, the CPU (51) of the microcomputer (200) operates according to the flowchart shown in FIG.

That is, the IFcI of the difference frame (hereinafter referred to as the difference frame) between the current frame written in the buffer section in step (2) and the predetermined frame specified by the user is 30.
It is determined whether or not there are 00 frames or more. If there are more than 3000 frames, a command signal CMD is generated to put the VTR (100) into fast forward or rewind mode depending on the direction of the predetermined frame in step (2), and the command signal CMD is sent via the input/output interfaces 71 and (55). ”(VTR(100)
The microcomputer (46) is supplied with the signal, and the process returns to step (2).

If l F Cl is not 3000 frames or more in step (2), it is determined in step (2) whether the mode is fast forward mode or rewind mode. When the mode is fast forward mode or rewind mode, it is determined in step (2) whether the difference frame IFcI is 500 frames or more.

When the number of frames is 500 or more, VT is set at step ■.
A command signal CMD for setting R (100) to 8x speed playback mode in the direction of a predetermined frame is generated and supplied to the microcomputer (46) of V'I'R (100) via the input/output interface (55), and step (2) Return to

If it is not the fast forward mode or the rewind mode in step (2), and if it is not 500 frames or more in step (2), it is determined in step (2) whether or not the difference frame IFcI is 60 or more frames. When the number of frames is 60 or more, a command signal CMD is generated to set the VTR (100) to 8x playback mode in the direction of the predetermined frame in step (2), and the command signal CMD is sent to the VTR via the input/output interface (55).
(100) is supplied to the microcomputer (46), and the process returns to step (2).

If the number of frames is not 60 or more in step (2), it is determined in step (2) whether the difference frame IFcI is 10 or more frames. If the number of frames is 10 or more, in step
Generates a command signal CMD to set the double speed playback mode to the VTR (100) via the input/output interface (55).
The microcomputer (46) is supplied with the signal, and the process returns to step (2).

If it is not 10 frames or more in step (2), it is determined in step (2) whether the difference frame IFcI is larger than O frame. When it is larger than O frame, in step [phase], a command signal CMD is generated to set the VTR (100) to 1/10 times speed playback mode in the direction of the predetermined frame, and the VTR (
100) to the microcomputer (46), and return to step (2).

If it is not larger than the O frame in step (2), that is, the θ frame, a command signal CMD is generated to set the VTR (100) to Bose mode (still playback mode) in step (2), and the command signal CMD is sent to the VTR via the input/output interface (55). (100) is supplied to the microcomputer (46), and the search is completed.

Also, during such a search, the CPU (51) of the microcomputer (200) sends a command signal CMD for muting the VTR (100) 17) video signal and audio signal.
V through the input/output interface (55).
The signal is supplied to the microcomputer (46) of the TR (100).

This example is configured as described above, and based on the user's operation of the controller (300), the microcomputer (206)
The command signal CMD is sent from the PU (51) to the VTR (100
), and the VTR (100) is controlled to the operating state specified by the user.

When the user instructs a search to reproduce a video signal of a predetermined frame, the VTR (10
0) is sequentially switched to perform a search.

For example, when the first difference frame IFcI is 3000 frames or more, the modes of the VTR (100) are set in the following order: fast forward mode or rewind mode - 8x playback mode - 1x playback mode - 1/10x playback mode -> Bose mode. The search is performed by switching sequentially.

Also, my when searching: 17 (200) (7) CP
Command signal CM D-I for muting the video signal and audio signal of the VTR (100) from U (51)
A muting circuit (45) for the video signal system and the audio signal system, which is supplied to the microcomputer (46) of J<VTR (100).

(73) and (74) are controlled by the microcomputer (46), and the video signal SV, audio signals SL, SR are output terminals
44>, (77) and (78) are not output.

Therefore, according to this example, since the video signal and the audio signal are muted during the search, the screen of frames halfway up to the predetermined frame to be searched will not be displayed. For example, when used in a videoless bonder, no intermediate correct answer screen is displayed, and the educational effect does not deteriorate. Therefore, according to this example, it is possible to improve usability for the user.

〔Effect of the invention〕

According to the present invention described above, the video signal is muted during a search to control the reproduction of the video signal of a predetermined frame, thereby preventing the display of frames halfway up to the predetermined frame. This is effective in applications where it is not desirable to show both sides of the middle, such as in a videoless bonder, and in this respect it is possible to improve usability for the user.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing one embodiment of the present invention, Figures 2 to 6
The figure is a diagram for explaining the same, and FIG. 7 is a diagram for explaining the videoless bonder. (45), (73) and (74) are muting circuits, (100) is a VTR, (200) is a microcomputer,
(300) is a controller.

Claims (1)

[Claims] In a magnetic reproducing device that reproduces the video signal from a magnetic tape in which a frame code is superimposed on the video signal and recorded on an inclined track, the video signal is muted during a search. Features a magnetic reproducing device.