JPS60243806A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the noise picture at the part where recording is stopped, by constituting a rotary head type magnetic recording and reproducing device in such a way that no-signal parts can be eliminated from a magnetic recording medium when the medium is reproduced at the time when signal recording is stopped. CONSTITUTION:When a stop button which is not shown in the figure is depressed under a recording condition with this rotary head type magnetic recording and reproducing device, the erasing current flowing to an FE head 5 is turned off and full-width erasing is stopped. Under this condition, a control signal ( I ) 1 is delayed by a delay circuit ( I ) 21 and a recording amplifier 4 operates until the starting point of the track recorded by a rotary head 6 passes a point A, but, after the stop button is depressed, a switching circuit 24 is switched and non-modulated frequency-multiplexed recording signals 23 of white level are recorded. While the signals 23 are recorded, a drum and capstan are also continued rotating by means of a delay circuit (II) 22. If the timing of each control signal ( I ) 1 and (II) 8 is adjusted during this period, no no-signal section of a distance (l) is left on a magnetic tape 7.

Description

[Detailed description of the invention] [Technical field of the invention] This invention L1 A rotating head attached to a drum,
A helical erase head that has a full-width erase head mounted perpendicular to the longitudinal direction (width) of the magnetic tape at a certain distance from the point at which recording begins on the magnetic tape (magnetic recording medium).
The present invention relates to a rotary head type magnetic recording/reproducing device such as a scan type VTR.

[Prior art]

Conventionally, this type of rotary head type magnetic recording/reproducing device is as follows:
There was one shown in Figure 1. FIG. 1 is a block diagram showing a conventional rotary head type magnetic recording/reproducing device. In the figure, 1 indicates a bias oscillator (FBHEAD 08C) 3 for supplying an erase current to the full-width erase head 5, and a recording amplifier (REC) for recording the recording signal 2.
This is a control signal (I) that controls AMP)4. 6 is a rotary head, 7 is a magnetic tape, 8 is a control signal (n) for a drum control circuit 9 and a capstan control circuit 110, 10 is a drum motor, and 12 is a cabstan motor.

In general, in a rotating head type magnetic recording/reproducing device such as a helical scan type VTR, a full-width erasing head 5 (hereinafter referred to as , FE head) is attached.

During the recording state in which the magnetic tape 7 is running in the tape running direction R1, the bias oscillator 3 operates in response to the control signal (I) 1, and the bias oscillator 3 operates as shown in FIG.
An erasing current flows through the E head 5, erasing the signal recorded on the magnetic tape 7, and the recorded signal 2 passes through the recording amplifier 4 and is transferred onto the magnetic tape 7 by the rotary head 6 attached to the drum 15. will be newly recorded. Further, during recording, the drum control circuit 9 and the capstan control circuit 11 are in operation, and the drum motor 10 and the capstan motor 12 are rotating, respectively.

When recording is stopped from the above-mentioned recording state, the control signal (■) 8 becomes Low level (L level). High level (H level) K is assumed]
Since the drum control circuit 9 and the capstan control circuit 11 stop operating, the drum motor 10 and the capstan motor 12 also stop, respectively. At approximately the same timing, the control signal (I) 1 also goes to L level, the erase current sent from the bias oscillator 3 to the FE head 5 turns off, stopping full-width erase, and the recording amplifier 4 turns off. The recording signal 2 is also no longer sent to the rotating head 6.

FIG. 3 shows the operation keys and each control signal (I) 1, (
II) shows the relationship with 8.

As explained above, when the operation mode changes from recording to stop, the rotary head 6 is moved in the rotary head scanning direction R2.
The state of the signal recorded on the magnetic tape 7 by the fourth
As shown in the figure. Since the FE head 5 is attached at a predetermined distance from the population of the drum 15, as shown in FIG. 2, the FB head 5 erases data from after track a to point A, as shown in FIG. An erased portion (no signal portion) B is generated. Here, track a is the track recorded just before recording stopped, and point A corresponds to the part where the erase current of the FE head 5 is turned off. Next, when you play this part, after playing track a, the screen becomes a noise screen, and if any signal was previously recorded, that signal will be played sequentially from point A, but it will not be completely Since the signal for one track is reproduced after track b, a noise screen appears at the bottom of the screen during that time. Also,
When performing splice recording, there is a method of rewinding several tracks and recording over the track where the signal was recorded before stopping, so that the recorded portion is not lost when recording is stopped and restarted. However, if the point at which recording starts again falls on the no-signal part B between trunk A and trunk A, a noise screen appears at the recording joint and is easy to visually detect. It was necessary to be chosen as before. Furthermore, when frequency-multiplexing a frequency-modulated audio signal together with a video signal, reproducing the no-signal portion B shown in FIG. 4 results in noise, so the audio output is
There are drawbacks such as the need to apply muting that responds immediately after track a.

[Summary of the invention]

This invention was made with the aim of improving the above-mentioned drawbacks of the conventional devices.When stopping signal recording in a magnetic recording/reproducing device, signal recording is continued after stopping the erasing means using the FE head. By providing a means to eliminate no-signal parts on the magnetic recording medium, there will be no noise screen when playing back the part where recording has stopped, and the audio output will be reduced when playing back the above-mentioned part. The present invention provides a rotary head type magnetic recording/reproducing device that eliminates the need for muting.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram showing a rotary head type magnetic recording/reproducing apparatus which is an embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same reference numerals. The detailed explanation will be omitted. As shown in the diagram, recording amplifier 4 and drum
The motor 10 and the carburetor tongue motor 12 are controlled by a control signal (■) 1 and a control signal (n) in order to continue operating for a certain period of time even if a stop button (not shown) is pressed.
In order to have an off-delay in 8, a delay circuit (DELAY circuit) (I) 21 and a delay circuit (II) are installed, respectively.
22 is provided in addition to the configuration of the conventional device shown in FIG. Further, 23L1 is a frequency multiplexed recording signal in which the frequency modulated luminance signal is set to a white level and the frequency modulated audio signal is not modulated; 24 is a switch circuit for switching the recording signal; 25
is the switch circuit 240 control signal.

In the rotary head type magnetic recording/reproducing apparatus configured as described above, when a stop button (not shown) is pressed in the recording state, first, the control signal (I) 1 goes to L level, the bias oscillator 3 turns off, The erase current flowing to the FB head 5 is turned off to stop full-width erase. Here, the rotating head 6
The control signal (■) 1 is delayed by the delay circuit CI) 21 until the start point on the track to be recorded passes through the above-mentioned point A. During this time, the recording amplifier 4 continues to operate, but the stop button is pressed. The rest is the switch circuit 24ri
Then, a frequency multiplexed recording signal 23 is recorded in which the white level frequency modulated luminance signal and the frequency modulated audio signal (in the case of recording a frequency modulated audio signal) are unmodulated. Meanwhile, the drum 15 and capstan (not shown) are also connected to the delay circuit (II) 2 to the control signal (■) 8 of each drum control circuit 9 and capstan control circuit 11, respectively.
Rotation is continued by adding a delay by 2. The signals recorded on the magnetic tape 7 at this time are schematically shown in FIG.
)1, (n)8 is clearly shown in FIG. However, here, the switch circuit 24 is
It is assumed that the signal falls to the frequency multiplexed recording signal 23 side at H level. As shown in FIG. 4 above, when the FE head 5 stops erasing, Tmz, /VC However, if the relationship (■ is magnetic tape speed) is established,
There are no signal areas on the magnetic tape 7.

Considering the case of next trap and transition recording, the sixth point is to stop recording from the recording state and then start recording again.
If you move a few tracks after track a in the figure, a blank screen with several fields will be played back, but since it is visually a white screen, it is hardly noticeable compared to the noise screen, so recording will start again. A margin of up to several tracks after track a can be expected.

〔Effect of the invention〕

As explained above, in a rotary head type magnetic recording/reproducing device, when stopping signal recording, a means is provided to continue signal recording after stopping the erasing means by the FB head, and a means is provided to continue signal recording after stopping the erasing means by the FB head. Since it is configured to eliminate no-signal parts, there is no noise screen when playing back the part where recording was stopped, and there is no need to mute the audio output when playing back the above-mentioned part. In the case of recording, it is possible to have an excellent effect such as being able to estimate the margin for restarting recording by several fields backward.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional rotary head type magnetic recording/reproducing device, and FIG. 2 shows the positional relationship between the full-width erasing head and the rotary head in the rotary head type magnetic recording/reproducing device shown in FIG. 1, viewed from above the drum. FIG. 3 is a timing chart of each control signal in the rotating head type magnetic recording/reproducing device shown in FIG. FIG. 5 is a block diagram showing a rotary head type magnetic recording/reproducing device according to an embodiment of the present invention, and FIG. 6 is a diagram showing the state of recording on a magnetic tape when Figure 7 is a timing diagram of each control signal in the rotary head type magnetic recording and reproducing apparatus of Figure 5. . In the figure, 1...control signal (I), 2...recording signal, 3...bias oscillator (FE HEAD 08C)
), 4... Recording amplifier (RECAMP)
, 5... Full-width erase head (FE head), 6... Rotating head, 7... Magnetic tape, 8... Control signal (I
I), 9... Drum control circuit, 10... Drum motor, 11... Capstan control circuit, 12... Cab stan motor, 15... Drum, 21... Delay circuit ( I), 22...Delay circuit (II), 23...
・Frequency multiplex recording signal, 24... switch circuit, 25
. . . is a switch circuit 240 control signal. In each figure, the same reference numerals indicate the same or equivalent parts.・Agent Masuo Oiwa Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) In a magnetic recording and reproducing apparatus that is equipped with an erasing means using a full-width erasing head and records and reproduces video signals on a magnetic recording medium, when signal recording is stopped, the signal continues after the erasing means using the full-width erasing head is stopped. A rotary head type magnetic recording and reproducing apparatus, comprising means for continuing recording, and means for stopping signal recording after the full-width erasing head finishes recording on the erased portion of the magnetic recording medium. (2) The means for continuing signal recording after stopping the erasing means using the full width erasing head records a recording signal that is a frequency signal corresponding to a white level signal. The rotary head type magnetic recording and reproducing device described in 1.