JPH0244363Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a magnetic recording/reproducing device such as a video tape recorder (VTR), and more particularly to a magnetic recording/reproducing device with improved continuous shooting.

(Prior Art) In recent years, with the development of electronic technology and precision processing technology and the improvement of recording and reproducing technology, for example, the development and commercialization of video signal recording and reproducing devices have been actively carried out.

In particular, for example, in a helical scan type video tape recorder (VTR) that uses magnetic tape as a recording medium, the end of the signal recording part (the end of the already recorded part) of the magnetic tape on which video signals, etc. have already been recorded. It is designed to allow continuous shooting with a so-called back space, in which the beginning of the signal recording part (the beginning of the unrecorded part) of the magnetic tape on which new video signals, etc. are to be recorded is overlapped. There is something that has been done. This is what is done in electronic editing of magnetic tape in "assembly mode."

According to this backspace splicing, unrecorded portions (blank portions) are not created at the joints of recorded signals, and a reproduced image with clear joints can be obtained.

Here, the outline of backspace continuous shooting will be explained with reference to the timing chart shown in FIG. In addition, the horizontal axis in the figure shows time t, and the vertical axis shows the amount of tape travel.

When the VTR is in the recording mode (REC) and set to the pause mode (REC PAUSE) (timing position in Figure 4), the VTR temporarily stops recording and the magnetic tape also stops. (At this time,
The magnetic tape remains in the loading state. ) Furthermore, the magnetic tape runs in the opposite direction, rewinds a little from the tape position when recording stopped, and reaches the fourth position.
The magnetic tape stops at the timing position shown in the figure. Then, in this state, pause mode (REC
PAUSE) standby.

After that, when you cancel the pause mode (REC PAUSE) and start the magnetic tape again (timing position in Figure 4), the magnetic tape will move to the position where it was previously put into pause mode (timing position in Figure 4). (4th timing position)
The camera travels to the timing position shown in the figure, and starts recording the video signal again from this timing position, and thereafter enters the normal recording mode. Therefore,
This means that the tape position from the tape position at the timing to the tape position at the timing is recorded in an overlapping manner.

(Problem that the invention aims to solve) However, in the above-mentioned backspace splicing, the end of the signal recording part of the magnetic tape on which video signals, etc. have already been recorded (the end of the video already recorded part) Since the beginning of the signal recording section of the magnetic tape (the beginning of the unrecorded section) on which new video signals, etc. are to be recorded is overlapped, the information at the end of the already recorded section is always preserved. There was a problem that the data would be erased, which was particularly inconvenient when the recorded content was continuous.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technology and to provide a magnetic recording/reproducing apparatus capable of continuous recording without overlapping recording parts.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a gap G ₂ on the leading side in the direction of travel with respect to the tape, and a gap G 2 on the leading side that is arranged to maintain a predetermined distance from the gap G ₂ on the leading side. and has a trailing side gap G ₁ for recording the control signal of the regular position,
A double gap control head ₁ is provided so that the reproduction signal obtained by the leading gap _G2 and the reproduction signal obtained by the trailing gap G1 have opposite polarities. The present invention provides a magnetic recording and reproducing device characterized by the following.

(Function) In the magnetic recording and reproducing apparatus having the above configuration, the interval between the two gaps of the double gap control head is managed to be a predetermined value, and by detecting changes in the reproduction control signal, It controls the start of recording and allows continuous shooting without overlapping recordings.

(Embodiment) An embodiment of the magnetic recording/reproducing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a main part of an embodiment of a magnetic recording/reproducing apparatus according to the present invention.

In the figure, reference numeral 1 denotes a double gap control head, and this double gap control head 1 has two gap G ₁ , which are arranged at a predetermined distance a in the running direction (advancing direction) with respect to the magnetic tape T. G ₂ (double gap), and furthermore, the reproduction signal obtained by the gap G ₂ on the leading side in the traveling direction S with respect to the magnetic tape T and the reproduction signal obtained by the gap G ₁ on the trailing side are I try to make it have the opposite polarity. In other words, the winding method of winding C ₁ corresponding to the gap G ₁ and the gap G ₂
The winding method of the corresponding winding _C2 is reversed.
The winding C ₁ corresponding to the gap G ₁ and the winding C ₂ corresponding to the gap G ₂ are connected in series.

Further, the collector of an NPN transistor Q is connected to the connection point between the winding _C1 and the winding _C2 , and its emitter is grounded. Then, by applying a voltage from a terminal P connected to the base of the transistor Q, ON/OFF of the transistor Q is controlled. As will be described later, the transistor Q is turned on in recording mode, and turned off in assembly mode for continuous shooting.

One end of the winding C ₁ corresponding to the gap G ₁ on the trailing side is connected to the input end of an amplifier 2, and the output end of this amplifier 2 is connected to output terminals 4 and 5 via a Schmitt circuit (waveform shaping circuit) 3. Connected.

Note that the output terminal 4 is connected to a servo system circuit, and the output terminal 5 is connected to a control section (system controller) that performs system control of the recording/reproducing apparatus.

The gap _G1 on the trailing side of the double gap control head 1 is a gap for recording control pulses at regular positions {timing that maintains compatibility with conventional magnetic recording/reproducing devices (VTRs)}. , and also the gap G ₂ on the leading side
is located at a position preceding the trailing gap _G1 by a distance a.

Note that this advance portion is preferably about 0.4 to 0.6 frames, and the interval a is determined as follows.

FIG. 2 shows the relationship between control pulse intervals in the standard mode and long-time mode of the magnetic recording/reproducing apparatus. In addition, "long time mode" means that the running speed of the magnetic tape is 1/3 compared to "standard mode".
This allows for twice as many records. In other words, in standard mode, the tape advance is, for example, 33.35mm/
s, while in long-term mode it is 11.12mm/
It becomes s. Therefore, the interval at which control pulses are recorded is also 1/3 of the interval at which control pulses are recorded in the standard mode.

In the same figure, if the interval P ₁ of control pulses recorded in standard mode is 1.112 mm, then the interval of control pulses recorded in long-time mode is
P ₂ (=P ₁ × 1/3) is 0.371mm (=1.112mm × 1/3)
becomes. Further, the control pulse is recorded on the control track corresponding to one frame of the video signal, and is a 30 cycle (30Hz) pulse.

From these relationships shown in Figure 2, the gap interval a of the double gap control head is set to 0.6 frames in advance in the long-time mode: a = P ₂ + P ₂ × 0.6 = 0.371 mm + 0.222 mm = It becomes 0.593mm. The preceding portion having this interval a corresponds to 0.53 frames (=0.593/1.112) in the standard mode.

With the control head configured as described above, for example, when performing backspace splicing as described above, the VTR is placed in recording mode (REC) and transistor Q in Figure 1 is switched on.
By turning it ON, recording is performed using the trailing gap G in the normal position, and at a certain position, the recording is temporarily stopped in the pause mode (REC PAUSE), and the magnetic tape is also stopped (see Figure 4). timing position).

At this time, recording is stopped when the recorded control pulse is at "L level".

Furthermore, after rewinding the magnetic tape a little in the assembly mode, the transistor Q in FIG. 1 is turned off. Then, the end portion of the signal recording portion of the magnetic tape that has already been recorded is reproduced using the gap _G1 and the gap _G2 .

FIG. 3 shows the reproduced signal waveforms at each part of FIG. 1 during this reproduction.

In the same figure, waveform A is the gap G ₁ on the trailing side.
Waveform B shows the reproduced waveform due to gap _G2 on the leading side. These waveforms A,
As can be seen from B, pulse A ₁ of waveform A is delayed from pulse B ₁ of waveform B by a time corresponding to interval a, and is obtained as a pulse with a different polarity.

Waveform C is an output waveform obtained from the output terminal of amplifier 2, and waveform D is an output waveform obtained by processing (shaping) waveform C by Schmitt circuit 3.

As can be seen from this waveform D, immediately before the unrecorded portion of the signal (i.e., at the end of the signal recorded portion),
The duty ratio (length of "H level" period) of this pulse is changing. That is,
“H level” at the end of the signal recording part of the magnetic tape
The length of the period L _E is longer than the length L _O of the "H level" period of the signal recording portion of the magnetic tape before that.

Therefore, the “H level” (or “L level”) of this waveform D
Detecting the change in the length of the period of the signal recording section, i.e.
The software (control program) of the control unit (syscontroller) is changed so that the signal junction is detected and the recording circuit, etc. is controlled so that recording starts from this point. In this way, it is possible to take continuous shots without overlapping recording parts.

(Effects of the invention) As described above, the magnetic recording and reproducing apparatus of the invention has the following features.

You can take continuous shots without overlapping recording parts.

Control head and control unit (system controller)
All you need to do is change the software (control program) and leave the rest as is.

The control pulses recorded by the control head of the device of the present invention are exactly the same as the control pulses recorded by the conventional device,
Therefore, compatibility can be maintained and there is no fear of malfunction.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of an embodiment of the magnetic recording and reproducing apparatus according to the present invention, FIG. 2 is a diagram for explaining the configuration of an embodiment of the magnetic recording and reproducing apparatus according to the present invention, and FIG. The figure is a timing chart for explaining the operation of one embodiment of the magnetic recording/reproducing device according to the present invention.
The figure is a timing chart to explain backspace splicing. 1...Double gap control head, 2
...Amplifier, 3...Schmitt circuit, 4,5...
Output terminal, T...Magnetic tape, _G1 ...Gap on the trailing side, _G2 ...Gap on the leading side, _C1 ...Winding corresponding to the gap on the trailing side, _C2 ...Gap on the leading side Winding wire corresponding to the gap.

Claims (1)

[Scope of utility model registration request] A gap on the leading side in the direction of travel with respect to the tape, and a gap on the trailing side that is arranged at a predetermined interval from the gap on the leading side and for recording a control signal at a regular position, A magnetic device comprising a double gap control head configured so that the reproduction signal obtained by the leading gap and the reproduction signal obtained by the trailing gap have opposite polarities. Recording and playback device.