JPS60253003A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To shift the titled device to a recording state from a recording pause state, etc. without passing through a rewinding or reproducing state, and to eliminate a time loss by making a level transition of a recording head switching signal exist in a decelerating period of a capstan motor, when shifting the device to a recording standby state from the recording state, and also disconnecting a recording current to a recording head at the same time as the level transition. CONSTITUTION:A device which satisfies a condition that a time required for a recording tape speed as a capstan motor, which reaches zero from a prescribed value is smaller than a period corresponding to about one frame of a recording video signal is used. When executing a tie-recording, it is necessary to disconnect a current in a decelerating period (during tS) without disconnecting a recording current to a head before entering a deceleration. Also, when the recording current is disconnected on the way of a track, an RF (high frequency) signal is disconnected and the track is cut off on the way, therefore, it is always necessary to disconnect the recording current after one track has been recorded. In this way, the device is controlled so as to disconnect the recording current by a level transition timing of an SWP signal (a head switching signal made by a rotary phase signal of a head drum) after the motor has been shifted to a deceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a recording/reproducing apparatus, and more particularly to a helical scan type magnetic tape recording/reproducing apparatus.

BACKGROUND ART A recording and reproducing apparatus is called a VTR (video recorder), and this VTR is capable of so-called splice recording such as insert recording and assemble editing. In this case, this is done by moving from the recording state to the recording standby (pause) state and then back to the recording state, but one way to do this is to rewind the entire magnetic tape to some extent in response to a recording pause command, and then shift to the recording state. A common method is to start recording after applying capstan servo while reproducing a CTL (control tracking) signal.

In this method, in addition to the time loss of rewinding the tape and applying capstan servo, it is inevitable that a shift will occur at the editing point.

On the other hand, recently the so-called 8
Tomo V 71"R was proposed and the retail name is this VTR-'
A so-called 4-frequency pilot tracking method is used instead of the cHCTL method. For this reason, when performing the so-called splice recording mentioned above, in this four-frequency pilot tracking system, the signal system needs to be put into the playback state and then the tracking servo is applied before shifting to the recording state. Therefore, there is a drawback that there is a time loss in reaching a stable state due to switching of the recording/reproducing amplifier system, switching of the signal system, etc.

SUMMARY OF THE INVENTION An object of the present invention is to enable continuous recording when transitioning from a recording state to a recording pause state without going through any tape rewinding or playback state. It is an object of the present invention to provide a recording and reproducing device that can perform accurate recording and reproducing.

The recording and reproducing device according to the present invention satisfies the condition that both the time required for the recording tape speed to reach zero from a specified value and the time required for the recording tape speed to reach the specified value from zero are short over a period equivalent to one frame of the recorded video signal. The capstan motor has sufficient characteristics to satisfy the requirements, and the capstan motor is designed so that there is a level transition in a predetermined direction of the recording/head switching signal during the deceleration period of the capstan motor when transitioning from the recording state to the recording standby state. The present invention is characterized in that it includes means for controlling the deceleration start timing, and means for cutting off the recording current to the recording head at the same time as the level transition of the recording gutter switching signal.

In addition to the above-described configuration, another recording/reproducing apparatus according to the present invention further includes a level transition of the recording throat switching signal in the predetermined direction during the acceleration period of the capstan motor when transitioning from the recording standby state to the recording state. The present invention is characterized in that it includes means for controlling the acceleration start timing of the capstan motor, and means for starting supply of recording current to the recording head simultaneously with the level transition of the recording throat switching signal.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of an embodiment of the present invention, in which the rotation of a capstan servo 1 is controlled by current control from a drive power source 2, and this drive current is controlled by a current switching circuit 3. be exposed. The switching operation of this current switching circuit 3 is performed based on the output of a controller 4 using a microprocessor such as a microcomputer, and this controller 4 receives a record (RE) from a keyboard (not shown).
C) A head switching signal (a switching signal that is generated based on a command signal, a recording standby (RECPAUSE) command signal, and a rotational phase signal of a henodrano (not shown).
WI), etc., the above-mentioned cutting operation command for the current switching circuit 3 and on-on control command for the head recording current are generated according to a predetermined procedure.

FIG. 2 is a time chart illustrating the operation of the apparatus shown in FIG. 1, in the case where there is a recording pause command at time t1 in the recording state and a recording command is issued at time t3 in this recording pause state. , is a diagram showing the relationship between the SWP signal phase, the tape speed, and the on/off timing of the recording current to the recording head.

This is the song recorded on the track at the edit point during splice recording! In order to minimize ll, it is necessary to control the capstan motor (recording tape) so that the deceleration state in which it reaches zero from the specified speed and the opposite acceleration state form characteristic curves (straight lines) that are symmetrical to each other. . In addition, in order to completely prevent card bands (gaps between tracks) from occurring at editing points, it is necessary to suppress the tape feed amount to within 1 track pitch during the acceleration/deceleration period, including the constant speed period of the recording tape. Become. Furthermore, in order to prevent the recording track width of the edit point from becoming too narrow, the tape feed amount during the acceleration/deceleration period including the constant speed period must be equal to or greater than the trunk pitch. Therefore, it is desirable to set the table feed during the acceleration/deceleration period including the constant speed period - 11Vi1) to be constant.

Now, for the sake of simplicity, it is assumed that the acceleration and deceleration at the start and stop of the keep methane are both constant accelerations and decelerations and have the same absolute value. The time required for acceleration and deceleration at this time is wotS, and the constant speed period wotN is the constant speed period required to obtain a tape feed amount of 1 track pitch in combination with the acceleration and deceleration periods.
shall be. Also, the specified tape speed during steady running is υ. , L is the amount of tape fed during the constant speed period and the acceleration/deceleration period, and τ is the time for one field (frame).

As mentioned above, by setting the tape feed amount during the acceleration/deceleration period including the constant speed period to one track pitch, the following equation is established.

tN L−υ0τ”, fvdt 〇−”°1N+−;″°Pa... (1) Furthermore, t=0
The reference point is the recording pause command time t.

(This is at the time of the level transition of the SWP signal (in Figure 2, the timing of transition from high level to low level).fi)
The following equation is obtained.

tN-D-(No.) t8...(2) The condition is to use a Capnutan motor that has sufficient force characteristics to satisfy the condition of equation (2) (,F)ts<2τ (frame period). Become.

Furthermore, in order to perform continuous recording v, it is necessary to cut off the recording current to the head during the deceleration period (between tsQ) rather than cutting off the recording current to the head before starting deceleration. Also, if you turn off the recording current in the middle of a track, the RF (high frequency) signal will be cut off and the track will be cut off in the middle, so it is necessary to turn off the recording current only after recording one track. . For these reasons, the recording current is controlled to be cut off at the timing of the level transition of the SWP signal after the shift to deceleration. Then, the amount of tape "ON" sent in the trench where the recording current is cut off is tN L()N-", fIJ o CIL"" υo (
τ's/2 ) + (/s) tB v.

Two υ. (τ-t, /8) ・・・・-・(3) At this point, UL is used to connect the tracks completely without bending. N
- This means that u(1),
(This means that t8-0 from Equation 31, so as a result, track bending inevitably occurs and is unavoidable. Therefore, in order to eliminate track bending sound, it is necessary to make ts as small as possible. However, the limit of ts is several ms.As a practically possible value, for example, t8-τ
Then, (3) formula Niji I, oN-vo(τ-'/8)
−(′7//8)υ. τ-(7//8)L·(4), and the recording pause state is entered after the track has curved by 125%. The state of this song V is shown in the dotted line track 5 in FIG.

Next, when moving from this recording pause state to the recording state,
Contrary to the above (in SW 1 after the start of acceleration), the head recording current is set to λ at the transition timing from the low level to the high level of the signal. At that time, the head to which recording current is supplied is controlled so that the head is in the opposite direction to the head recorded just before entering the recording pause state. By doing so, the field of the recorded video signal before and after the editing point is The phase has continuity.

Furthermore, in the case of the so-called four-frequency tracking method, it goes without saying that control is performed to maintain the continuity of the tracking pilot signal. four pilot frequencies f, ~f4 for each field, f, -, f, -f3-f
For example, if a pilot signal of f2 is recorded immediately before entering the recording pause state, then when entering the recording pause state and the recording state next time, the pilot signal of f2 is recorded one by one in the order of f2. The signals are recorded in the above order.

In this case, the track will curve in the opposite direction from when it moved from the previous recording to the recording pause, resulting in a track 6 indicated by a dotted line in FIG. 3. In this case as well, to reduce the gart band, the head width needs to be 12.5% wider than the track pitch. For example, if the track pitch is 20 μm, the gart band will not occur if the head width is 22.5 μm or more wider. .

Also, the maximum possible RE' signal drop in this case is 20
log (7/g) = about 1.2 dB, which is a level with almost no effect. The example described above is for t8-τ (period equivalent to the L field, approximately 16.7 m5). This shows the values for the start timing of deceleration and acceleration, the on/off timing of the recording current, and the head width.As can be seen from this example, if you know ts and its variations based on the characteristics of the capstan motor, With the above procedure, the l:ri710 deceleration timing and head width can be calculated, and if the controller 4 is programmed so that the capstan motor acceleration/deceleration timing and recording current on/off timing can be commanded in advance, there will be no problem. Splice recording becomes possible without any operations such as tape rewinding or playback.

Even if a capstan motor with t822τ, which is the worst condition, is used, the level drop of the RF signal is 2009 (3/4) = -2,s dt3, and DW
(Head width)=1. zs'T”P() rack pitch) =
If the thickness is 25 .mu.m, guard bands will not occur and splice recording can be performed without causing any practical problems.

Effects of the Invention As described above, according to the present invention, it is possible to transition to the recording pause state, etc., without going through the rewinding or playback state, so that the time ronu 75 is completely eliminated and a good transition is achieved. Recording becomes possible.

[Brief explanation of drawings]

FIG. ii is a block diagram of an embodiment of the present invention, FIG. 2 is a time chart explaining the operation of the blocks in FIG. 1, and FIG. 3 is a diagram showing the recording track at an editing point. Description of main parts: Capstan motor 2, current switching circuit 4, controller 5, 6... Recording track Applicant: Bionib Co., Ltd. Agent Patent attorney: Rattan material Motohiko 2121

Claims (2)

[Claims] (1) VC until the recording tape speed reaches zero from the specified value
A capstan motor with sufficient characteristics to satisfy the condition that the time required is less than a period equivalent to approximately one frame of a recording video signal, and a capstan motor having sufficient characteristics to satisfy the condition that the time required is smaller than a period corresponding to approximately one frame of a recording video signal, and recording during a deceleration period of the capstan motor when transitioning from a recording state to a recording standby state. means for fully controlling the deceleration start timing of the capstan motor so that there is a level transition of the head switching signal; and means for cutting off the recording current to the recording head at the same time as the level transition of the recording throat switching signal. A recording and reproducing device characterized by comprising: (2) The characteristics are sufficient to satisfy the condition that both the time required for the recording tape speed to reach zero from the specified value and the time required for the recording tape speed to reach the specified value from zero for a period equivalent to one frame of the recorded video signal. The capstan motor is configured to set a deceleration start timing of the capstan motor so that, when transitioning from a recording state to a recording standby state, there is a level transition of a recording throat switching signal in a predetermined direction during a deceleration period of the capstan motor. means for controlling the recording current to the recording head at the same time as the level transition of the recording head switching signal; means for controlling acceleration start timing of the capstan motor so that a level transition of the recording throat switching signal occurs in the predetermined direction; 1. A recording/reproducing apparatus comprising: means for starting supply of recording current.