JPH0534723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to magnetic recording and playback, and more particularly to a method and tape recording and playback apparatus for achieving a signal time base variation effect.

Extensive research and effort in the field of data recording and playback has resulted in many improvements in devices for recording and playing back data on tape or other media. Many different formats have been developed, but one that records the video signal on a recording medium and feeds the tape in a spiral around a cylindrical scanning drum has a simple tape advance drive and control mechanism;
It has many benefits on the electronics required, the number of conversion heads, the efficient use of tape, and the amount of tape required to record a given amount of material. A single transducer head can be used that reproduces information recorded on tape by spirally wrapping the tape around a rotating scanning head. When using a single head in a spiral tape recorder, two devices are available for wrapping the scanning head, commonly referred to as alpha and omega wrappers.

In alpha winding, the tape is introduced from one side,
It is completely wrapped around the drum and is commonly referred to as an alpha wrap because it resembles the Greek letter alpha alpha. Omega winding introduces the tape toward the drum, generally radially, passes it around a guide so that it contacts the drum surface, wraps the tape in a spiral around the drum, and exits the drum generally radially. pass around other guides. The tape generally resembles the Greek letter omega Ω. Both of these configurations are such that the tape is wound helically around the scanning drum, with the tape exiting at different points axially on the drum surface relative to the inlet. In other words, if the drum is oriented vertically, the tape will exit the drum surface higher or lower than when it first contacts the drum surface. Video or other data information is recorded on discontinuous parallel tracks placed at an angle to the longitudinal direction of the tape so as to obtain track lengths greater than the width of the tape. The angular orientation of the recording track is a function of both the rotational speed of the scanning drum itself as well as the speed of the tape being fed around the scanning drum. The angle therefore varies depending on the relative speeds of the rotating scanning drum and the tape being fed.

Therefore, if an information signal is recorded on tape at a predetermined angle resulting from accurate rotational scanning drum speed and tape advance speed, subsequent playback of the information signal should occur at the same speed. That is, the conversion head must follow the track accurately. If the tape speed changes during playback, such as slowing down or stopping, the transducing head will no longer accurately follow the recording head and may cross adjacent tracks. Failure to accurately follow the recorded track during playback results in noise and other undesirable signal effects appearing in displayed information, such as video images. Although various conventional devices have been proposed to reduce such undesirable effects due to lack of memory, such devices do not provide full coverage even during normal tracking at speeds designed to be identical to those used during recording. Not really successful.

Spiral tape recorders designed to create special modified timebase effects have not been successful to date due to the sudden noise generated during playback by the conversion head crossing over from one track to another. I wasn't there. For example, slow motion effects in video recording necessarily require that the data be repeated more than once during playback, so as to slow down the visible motion to create such an effect. If data is recorded without redundancy, one track must be played repeatedly to accomplish this, and the tape speed must therefore be varied. The path on the tape that must be followed by the transducing head is substantially different than during the recording process. There is also a significant difference in stop or frame still behavior when the tape advance is stopped and the video head rescans a pair of adjacent tracks many times.

Devices have been proposed to reduce or eliminate the noise bands generated by track crossings, but
Not actually successful. Some prior art devices for video signals include switch means adapted to select the video conversion head having the maximum output power.
Although two video conversion heads are used, this method is unsuccessful because neither video head is exactly on the video track for its entire length, and the signal-to-noise ratio is therefore poor. Other conventional devices for video signals use techniques such as synchronized pulse line-up and vary the tape guiding means around the scanning drum to minimize cross-over effects by varying the helical angle. I'm trying to. None of these methods have been particularly successful, and slow motion, stop motion, and fast motion effects have not heretofore been achieved in spiral videotape devices.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved apparatus for achieving the effect of changing the time base in a tape recording and reproducing apparatus.

In particular, it is an object of the present invention to provide a device of the type described above for performing time reference changes by precise repositioning and control of the tracking of the transducer with respect to the track along the tape of a tape recording and reproducing device.

Furthermore, it is an object of the present invention to provide a tape recording apparatus with the ability to:
The object of the present invention is to provide an improved apparatus of the type described above for achieving slow motion, stop motion, high speed motion, and other modified time base effects.

Another object of the invention is to provide an improved device of the type described above in which variable slow motion speeds within predetermined limits are possible in the forward and reverse directions of the tape advance motion.

Broadly speaking, the present invention relates to an apparatus for achieving a modified time base effect in the art of reproducing and recording information signals on media. Although the invention is suitable for many different types of recording devices, it is particularly useful in creating modified or special motion effects from a video signal. Although a variety of video recording formats exist and are applicable to the present invention, the present invention is particularly useful for spiral tape recording devices for achieving special motion effects such as slow motion, stop motion, and high speed motion. In this case, slow motion and fast motion are performed in forward and reverse directions. Accordingly, the present invention can be used in video tape recorders having a four-part helical arch recording format, as well as various helical tape recording formats.

Although the invention has been specifically described with respect to an omega-wound video tape recorder, it is equally applicable to an alpha-wound helical tape recorder. Additionally, although the present invention is described with respect to a 360° omega winder (although the tape does not contact the scanning drum a full 360° due to tape input/output dimensional requirements), it is possible to use a device with less than 360° winding, e.g., one or more heads. It is also applicable to 180° spiral videotape recorders. The invention is applicable to devices in which the scanning drum can move in either direction of rotation and the tape can be introduced above or below the exit path and moved in either direction along the scanning drum. The relationship between head rotation, tape feed direction and tape guide path, i.e. by introducing the tape above or below the exit path,
Although eight different geometrical relationships can be expressed, only one of which will be specifically discussed here, as shown in the direction of the arrow in FIG.

Broadly speaking, the present invention provides a method and apparatus for accurately positioning a transducer head for following a track and, if necessary, rapidly positioning the transducer head at the beginning of the desired track to be followed next. Regarding. The next track to be followed is determined by the selected operating mode. In the reproduction of video signals, various modes are provided including stop motion, or still frame effects, as well as slow motion effects, speed-up, or fast motion effects. Still other modes of operation include a skip field signal and compensated playback (as well as a monitor mode) which greatly increases the amount of time that can be recorded on a given length of tape;
Effectively skipping multiple fields, eg recording one of each 60 fields. The device allows the tape feed speed to vary over a wide range, yet allows for accurate tracking. If a fast motion effect is to be achieved, the tape feed rate must be increased; for a slow motion effect, the feed rate must be reduced. A stop operation requires the same field to be played over and over again, and in such conditions the tape is not moved at all and the relative motion between the tape and the transducer head is provided by the rotation of the scanning drum that supports them. If the video conversion head supported by the scanning drum is held in a fixed position, since changes in tape advance rate will also change the head-to-track angle,
If the tape feed speed changes, the track will not be followed accurately.

The invention comprises means for moving the converting head transversely or laterally to the direction of the upper track, and then selecting the position of the head so as to position it precisely on the track to begin following the other track. If the head position is actually changed, then that track is a track other than the next adjacent next track if the head position is actually changed. During recording, one complete rotation of the scanning drum causes the transducer head to record a track in a predetermined angular direction relative to the length of the tape, and at the end of the sweep, movement of the tape causes the recording head to record the next adjacent consecutive track. is gradually displaced downstream by a predetermined distance so as to start. In this way, the tracks are recorded parallel to each other and have a constant spacing from adjacent tracks, assuming the tape advance rate is held constant along with the rotational speed of the scanning drum supporting the recording transducer head. That is, the center-to-center distance of adjacent tracks is approximately constant in the absence of geometrical errors introduced by stretching, other changes in tape dimensions due to temperature or humidity, or erroneous tensioning mechanisms in tape advance.

In FIG. 1, numeral 10 designates a spiral video head scanning drum with the portion broken away in FIG. The drum consists of a rotatable upper drum part 12 and a fixed lower drum part 14, the upper drum part 12 being fixed to a shaft 16 which is rotatably supported on a bearing 18 which rests on the lower drum part 14; The shaft is driven by an operably coupled motor (not shown) in a conventional manner. The scanning drum 10 has a video conversion head 20 supported by a rotating drum section 12 and mounted on an elongated movable support element 22 mounted at one end of a cantilevered support 24 fixed to the upper drum section 12. It is provided. Element 22 is preferably of the type that flexes across the recording track during playback, the amount and direction of its movement being a function of the applied electrical signals, as will be described below.

As shown in FIG. 1, scanning drum 10 is part of a spiral omega video tape recorder having magnetic tape 26 advancing in the direction of arrow 46 toward the drum. In particular, the tape is introduced into the drum face from the lower right side as shown, fed around guides 28 that bring the tape into contact with the outer surface of the fixed lower drum section 14, and then fed as it exits the scanning drum after recording or playback. Second guide 3 to change direction
It passes almost completely around the drum until it passes around 0. As shown in FIGS. 1 and 4, the omega-wound videotape recorder has a structure in which the incoming tapes do not interfere with the outgoing tape in that they do not need to cross each other as in the alpha-wound format; To this end, the lower portion of the output tape can be superimposed on the upper portion of the lead-in tape to provide a non-recorded frenulum that can be used for audio and control signals, etc. The superimposed segment ll is shown in the lower part of the tape shown in FIG.

As shown in FIGS. 1 and 3, the clearance required for the tape inlet and outlet is such that the tape does not make full 360 DEG contact with the scanning drum surface. However, this gap preferably does not exceed a drum angle of more than 16 degrees, which would result in information dropout. The dropout is preferably selected such that the lost line interval does not occur during a valid video line and the start of the track scan is field synchronized. As described later,
Omega winder dropouts are used to benefit the operation of the present invention.

As previously mentioned, the transducer head 20 is an elongated, movable, preferably flexible transducer head 20 that supports the transducer.
Element 2 consisting of two longitudinal layers, i.e. a bimorph element
2. It preferably consists of a thin leaf bimorph or two-layer element which exhibits a dimensional change in the presence of an electric or magnetic field, with two polar axes oriented such that it is deflected or bent by the application of an electric or magnetic field, etc. Bimorphs or bimorph cells consisting of piezoelectric layers are preferred, but at least one layer is piezoelectric, electrostrictive or magnetostrictive.
It can be constructed from two suitably attached layers.

Deflectable element 22 is connected to conductor 32 from control circuit 34.
This is effective for moving a converting head 20, which is disposed perpendicularly to the tape surface, as shown in FIG. 2, in response to an electrical signal applied through the tape. head 20
extends slightly beyond the outer circumferential surface of rotating drum portion 12 and extends through an opening 36 in the outer surface. A support is attached to the rotating drum section 12 for positioning control relative to the magnetic tape by using thin leaf piezoelectric bending elements to suspend and cantilever the transducing head for positioning control relative to the magnetic tape. One end is fixed by 24. Deflectable element 22 is thus adapted to sweep or curve deflection of the transducing head in response to an applied electric field signal. The fixed end deflectable element 22 is arranged to have a direction of relative movement of the head with respect to the magnetic tape, ie a direction of bending movement of the free end supporting the transducing head along a path transverse to the direction of the recording track. Preferably thin leaf piezoelectric deflectable elements extend from the rotating drum perpendicular to the plane tangent to the recording surface at the head-to-recording surface boundary and generally parallel to the direction of relative head-to-recording surface motion. The transducer head 20 is operatively connected to the magnetic tape such that in a direction transverse to the direction of relative motion, the transducer gap is oriented with a gap length across the width of the deflectable element and a gap width across the thickness of the deflectable element. For engagement,
It rests on the outer free end of the piezoelectric deflectable element 22.

A low mass, thin leaf piezo structure is preferred because it responds rapidly to positioning commands and follows changes in the command signal. In particular, the thickness of the deflectable element relative to its width should be such that no deflection or movement of the transducing head occurs in any direction other than transverse to the track length. Therefore, during operation of the device, by applying suitable signals for changing the position of the transducing head, the head is moved from one side to the other relative to the track being followed, and if appropriate error correction is made. Once the signal is obtained, the head can be moved to accurately follow the track during playback. That is, this correction signal is applied to element 22 to move the transducing head to match the track from the beginning to the end of one complete revolution of scanning head 10.

If the magnetic tape feed rate changes relative to the information recording rate, the effective angle of the helix changes and an error correction signal is generated to cause the transducer head to follow the track at a different angle. Since the deflectable element is movable in both directions, the tape can be fed around the scanning head at high or low speeds relative to the signal recording speed, and the element can be moved in either direction to follow the track being played. The head can be positioned.

FIG. 3 shows a segment of tape 26 having a number of tracks A through F, with arrows 40 and 42 indicating the direction of tape movement around scanning drum 10 and the direction of head scanning relative to the tape itself, respectively. The direction of the truck and the arrow shown in Figure 3 are
This corresponds to that caused by the movement of scanning drum 10 and tape 26 shown in the figure. Scanning drum part 1
Due to the constant feed speed and angular velocity of 2, tracks A to F are parallel to each other and approximately straight, forming an angle θ (for example, about 3°) with respect to the longitudinal direction of the tape, and the tracks are continuous from left to right during the recording operation. is generated. For example, immediately after track A is recorded at a constant scan rotation and tape advance speed, track B is recorded.
are recorded, so if these speeds are maintained during playback operation, conversion head 20 will
Track B is played back during continuous rotation immediately after playing back the information from.

If conditions are ideal and no distortion is induced, no error signal is generated to move the transducer head 20 across the track, so the transducer head 20 simply follows the next adjacent track without adjustment. . In other words, the converting head automatically moves to the starting point of playing the next track B after completing the playing of the information from track A. If the playback tape feed rate is varied relative to the record feed rate and the head is moved transversely to maintain accurate tracking over the playback of the track, then the next adjacent downstream track, track A. This is the position where track B would start playing if the track was completed. This occurs even when the tape is stopped or moving slower or faster than the recording advance rate.

In order to achieve special motion and other effects during reproduction of information signals recorded on videotape or other media, it is necessary to vary or adjust the tape advance speed around the scanning drum. To obtain a speed-up or fast-forward effect, the feed rate is increased relative to the speed used during recording. Similarly, in order to obtain a slow motion effect, it is necessary to reduce the feed tape speed around the scanning drum used during the recording process. The stop operation requires that the tape be stopped so that the transducer head on the scanning drum can repeatedly reproduce the information signal from a single track.

The device of the present invention can be placed in different operating modes, the forward or reverse motion effect is achieved, and its motion simply adjusts the tape feeding speed in the forward or reverse direction to obtain the desired motion speed during playback. You can speed up or slow down by adjusting. Once the direction is selected, the device automatically positions the transducer head to follow the track from start to finish, and then (if adjustment is required) adjusts the transducer head position to the beginning of the proper track. functions.

Broadly speaking, the present invention provides, under certain predetermined conditions, for resetting or moving the converting head transversely (with respect to the track) at the end of a track to a position corresponding to the start position of a track other than the next consecutive adjacent track. and does not reset or adjust the conversion head under other predetermined conditions. The decision to transversely move or adjust the transducer head depends on the mode in which the device is operated and whether the transverse motion is within predetermined limits that can be achieved. In other words, if the conversion head is moved the maximum amount in one direction, it cannot be moved further in that direction. The total range of movement is within practical limits achieved by the characteristics of element 22.

The manner in which the transducer head is controlled during various modes of operation is illustrated in FIG. 5 and will be described in particular with reference to FIG. 5e, with particular reference to the still frame or stationary mode of operation.

In the stop operation, i.e. still frame operation mode, the conversion head is reset at the completion of the track being played and is reset at the beginning of the track so that it can repeat as many times as required for the duration of the stop operation. need to be done. The track is thus effectively played over and over again as the tape remains stationary. Since the playback head follows a track during repeated playback, it must be reset by a distance equal to the track spacing d of the recording track in order to be correctly positioned to play that track. When the tape is stopped, the angle of the track is different from the angle it had during recording, so that its head is gradually adjusted during playback of the information signal on the track. Therefore, as the scanning drum moves along a track, the error correction signal causes the transducer head to move laterally to follow the track and is essentially in position to begin playing the same track. The one-track traversal distance d must be reset automatically. In the configuration shown in FIGS. 1 and 3, the track width is approximately 5.6 mils (5.6/1000 of an inch) and the center spacing d between adjacent tracks is approximately 8.7 mils. The deflectable element 22 shown in FIG. 2 is adapted to travel approximately 8.7 mils in either direction, and these design limits are
This is illustrated in the displacement pattern versus time diagrams of Figures 5j. Additionally, the scanning drum rotates at a constant speed of 60 revolutions per second such that the time to play each track is relatively constant at approximately 16.7 milliseconds in duration. In all of the patterns shown in FIGS. 5a-5j, the coordinate o position preferably represents the unbiased or home position of the transducer head, which occurs when no voltage is applied to the deflectable or movable element 22.

In particular, with respect to the still frame or stop motion displacement pattern for positioning the transducer head shown in FIG.
It has a sloped section labeled Regeneration following a reset section represented by a generally vertical line with a vertical reset distance of the mill. Therefore, when the transducer head is regenerating at the start of the track, it must be positioned approximately 4.35 mils above the home or zero position, and during the regeneration of the track, it must be moved progressively downward to lower the transducer head's position. to the lowest position approximately 4.35 mils below the center line or o-home position. At the end of a track, the transducer head must be moved transversely to a position to reset, ie start playing the same track again, and appropriate control signals are applied so that the deflectable element 22 up and down a total of 8.7 mils to accurately position the same track to begin playing again. This repetition occurs as long as the still frame is held.

Resetting the transducer head is accomplished by a generated pulse of proportional amplitude, determining a deflection of 8.7 mils. The pulse is generated automatically until inhibited, but is a function of the position of the transducer head near the end of playback, ie, at or near the lower point of the playback portion of the pattern shown in Figure 5e. If the transducer head position is detected to be below the home or o position at the end of the track scan, then a reset pulse is generated and the head is reset as shown. However, if the transducer head position is above the home or o position at the end of a track scan, the reset pulse is inhibited and the next track is started. In the absence of a control signal to reposition the conversion head, it is in a position to begin tracking the next adjacent track at the end of the previous track, as described above.
Thus, the lack of a reset pulse causes the conversion head to advance from track A to track B, a condition caused, for example, by generating an inhibit signal that inhibits the reset pulse. The manner in which signals are generated and inhibited will be further described in conjunction with the description of the operation of the circuit shown in the block diagram of FIG.

For a general description of the following displacement patterns for slow motion effects, reference is made to Figures 5b, 5c and 5d which show displacement patterns for slow motion effects. In these figures, the tape is recorded at 1/2 the speed
(Figure 5b), 1/5 (Figure 5c) and 1/10 (Figure 5d)
(Figure). These patterns indicate the number of repeats or plays that occur for each track, and this number is a function of the feed rate relative to the speed during the recording process. Therefore, if the tape feed speed around the drum is reduced to 1/2 of the recording speed, the scanning drum continues to operate at the same rotational speed of 60 revolutions per second, so each track is played twice. There is a need. Similarly, if the feed rate is 1/10 of the recording rate, each track will be played 10 times before the next track is played.

In the present invention, the number of reproductions is adjusted with respect to the tape feed speed, as will be described later. Regarding the slow motion displacement pattern shown in Figure 5, and with particular reference to Figure 5b, which shows the movement pattern of the transducer head when the tape advance speed is 1/2 of the speed used during recording, each track is The manner in which it is repeated will be explained. That is, each track must be repeated once before the next track is played. Thus, the first regeneration of track A deflects the conversion head approximately 4.35 mils down until it reaches the end of the track, and for the second regeneration of track A, it is reset to a total of approximately 8.7 mils upward. . Near the end of the second playback of track A, the conversion head approaches the detected home or o-deflection position and reset is inhibited to allow track B to scan. Similarly, the transducer head is deflected approximately 4.35 mils down as with track A, and the pattern is repeated from track to track as shown.

If the feed rate is further reduced, e.g.
In cases such as 1/5 and 1/10 of the recording speed shown in Figures 5 and 5d, the track is played back 5 or 10 times, respectively, as shown. For the displacement pattern of Figure 5c, the head is deflected downward starting from its home position during the first play of track A until it reaches the end of that track, and then the head is deflected downwardly on that track, which requires approximately 8.7 mils of displacement. It will be reset for playing again. The head follows its track many times in succession, and the downward displacement of each successive play progressively approaches the home position as the track physically moves around the scanning drum during successive plays. Therefore, the tape gradually moves upward along the spiral path. During the last playback of track A, the transducing head position near the end of playback is above o, the home position, and begins the first playback of the next track B.
Similarly, the gradual movement of the tape around the scanning drum shown in FIG. Truck A
and causes the head to start playing track B.

3 tape feeds that produce slow motion playback
From the above mentioned speeds, it can be seen that the track is played as many times as necessary (no matter how many times this happens) to ensure that the conversion head is at home, i.e. above the o position, at the end of the playback of the repeated track. . This condition is detected, reset is inhibited, and the conversion head begins playing the next adjacent track. The amount of travel during each reset is constant, approximately 8.7 mils for the device described herein, and the distance is equal to the track spacing d.

Figure 5j shows a displacement pattern for the transducer head, representing head movement during reversal or reverse tape feeding at normal playback speed. Fifth
Unlike the other patterns shown in the figure, track A
is shown on the right, and tracks B, C and D are continuous on the left, opposite the orientation of the other figures. This indicates a reversal direction, with the scanning drum following each track in the same direction as it was followed for slow motion and stop motion. That is, the scanning direction occurs from the top to the bottom of the sloped portion of the pattern of FIG. 5j, and a reset movement is made to position the conversion head for reproduction of the next desired track. Although the scanning drum moves in the same direction relative to the tracks during track playback, the tracks must be played in the reverse order relative to the order during forward playback. The displacement pattern shown in Figure 5j is for normal speed in that the tape is fed around the scanning drum at the same speed as used during recording, but in the opposite direction. As shown by the displacement pattern in Figure 5j,
The transducer head reset is larger than previously described, in fact it moves twice the distance of 8.7 mils, for a total of 17.4 mils, and all of this movement is required to precisely position the tape upstream, on the previous track. is necessary to traverse the two center spacings d.
This means that to play a track during slow motion or stop motion effects, the translation head can be displaced by a single center-to-center distance of approximately 8.7 mils to reposition the head to repeatedly play the same track. If you remember that it was necessary, you will easily accept it. If only one track is to be played prior to the track being played, further inter-track distances are required to position it at the beginning of the previous track. Therefore, in order to reproduce the information signal in the reverse direction at the normal speed, a total of twice the center distance d is required.

In order to slow motion in the reverse direction and repeat tape playback one or more times depending on the reverse tape speed, it is necessary to slow down the tape advance speed in the reverse direction. Figure 5i therefore shows a reverse 1/2 speed displacement pattern, with each track having two speeds before the next previous track is played.
Repeatedly. Thus, for example, since track C is first played, the transducer head is reset a distance of one center spacing, i.e., 8.7 mils, and track C is reset to 2d where the downward deflection of the transducer head produces a reset signal of double amplitude 2d. 2 until the bottom of the second playback is detected and the transducing head is deflected approximately 17.4 mils upwards positioning it at the start of track B.
The second time is played. The lower range of track B's first playback is 8.7 which causes track B to play a second time.
Up to about 4.35 mils of downward deflection, which is not enough deflection to generate a double amplitude reset pulse so that only mil deflections occur. In this way a slow motion effect in the opposite direction is achieved.
When the position of the transducer head at the end of a track is sufficiently displaced relative to the home position, a signal is generated that deflects the two track centers 2d, or about 17.4 mils.

The manner in which the circuitry of one embodiment of the controller associated with the present invention operates to produce the displacement patterns described above will now be described with respect to the block diagram of FIG. In accordance with the present invention, the controller includes a holder that holds the transducer in both directions relative to the length of the track as the tape is advanced at a selected speed different from the normal recording and playback speeds. generates a control signal for transversely deflecting the transducer, the control signal being applied to the first and second
a composite signal having signal components, the first signal component being selected to laterally deflect the transducer so that the holder follows a desired track during the transfer of an information signal on the tape. a ramp signal having a slope according to the difference between the speed at which the signal was applied and the normal speed, the second signal component being changed following the period to cause an information signal to be transmitted following the period; the holder positions the transducer to begin following a track, and the first signal component generated by the controller has an amplitude different from the amplitude of the second signal component. so that as the tape is fed at the selected speed, the transducer follows the track of interest during each period of transfer of an information signal, and following each period of transfer the information signal is transferred. is positioned to begin following the track to be transferred. As previously mentioned, the error correction signal, which is preferably a low frequency or varying DC level, is provided on line 52.
is applied to the integrator 50 via. When scanning a track, if it is within the deflection limits of element 22, the transducer head is adjusted to follow the track regardless of the tape advance speed. The integrator generates the first signal component, a ramp signal, the slope of which is a direct current taken from the head positioning servo circuit;
or determined by the low frequency error signal. The servo error thus modulates the slope of the ramp signal as the transducer head position error changes, and the output of the integrator appears on line 54 extending to the summing circuit that drives the transducer head movable element 22. In addition to the low frequency that is the first signal component, that is, the ramp signal in the form of a varying DC level error signal, vibration signals, high frequency error signals, etc., as well as the reset position in the displacement pattern shown in FIG. The resulting second signal component, the reset pulse, can be added to the decoding control signal used to drive the holder or positioning device supporting the transducer. Pulse generator 56 generates a reset pulse having an amplitude proportional to the desired one track deflection to be achieved by element 22. In other words, the magnitude of the reset pulse is equal to the center-to-center distance d, or 8.7 mils in the illustrated embodiment, plus the amount of deflection required to reset the transducer head, or 17.4 mils, which represents twice the center-to-center distance d. Determine the reset pulse that causes the displacement. Pulse generator 56 is adapted to generate pulses on output line 58 when the tape is being fed in the forward and reverse directions, and pulse generator 60 is adapted to generate pulses in certain conditions that occur only when the tape is being fed in the reverse direction. It produces an output pulse on line 62 of the same amplitude as that produced by generator 56. If a pulse appears on both outputs, adder 64 generates a pulse that is the sum of the two pulses, thus 2
A pulse is applied that causes a reset of the two center spacings. The reset pulse appears on line 66 extending to the input of integrator 50.

Forward tape feed mode level detector 68 monitors the integrator output and provides an inhibit output that inhibits pulse generator 56 from generating pulses at output 58 if the ramp signal is above the reset level at the end of the scan. A signal is adapted to be generated on line 70. Similarly, a reverse tape feed mode level detector 72 monitors the ramp voltage from the integrator 50 and inhibits the voltage on line 74 until the ramp signal reaches a predetermined level slightly more than one track above the level of the detector 68. Generate a signal. In the reverse mode, the inhibit signal inhibits the output on line 62 so that only a single track interval reset amplitude pulse is generated by pulse generator 56;
This pulse generator 56 is triggered in response to receipt of the forward end of a scan command on a line 76 taken from a tachometer mounted for rotation with the rotatable drum 12 of the scan drum. The tachometer is of conventional design, producing a tachometer pulse for each rotation of rotatable drum 12.
For convenience, the tachometer is mounted on the rotatable drum 12 so that it occurs just before dropout. A tachometer processing circuit conventionally used in helical recorders is used to provide timing pulses from the scanner tacho pulse circuit to the helical recorder used to control operating functions. A pulse generator 56 provides a reset pulse to the integrator 50.
To trigger the scan command, the leading edge of the scan command is generated from a scanner tacho pulse that is applied prior to the end of the scan of the previous track. The tach pulse associated with the previous track is processed by a conventional counter included in the tachometer processing circuit so that it appears on line 76 before the end of scanning the current track.

The circuit is operable to provide waveforms at the output of the integrator for various modes of operation that are generally symmetrical or mirror images of the displacement pattern of FIG. 5 for the various modes. As an example, a forward 1/2 speed slow motion with the displacement pattern shown in Figure 5b results from the integrator output waveform shown in Figure 7a. By comparing the waveforms of Figures 5b and 7a, it is clear that the shapes are only reversed. Thus, in FIG. 7a, integrator 50 produces an output waveform that rises during track regeneration, the slope of the ramp portion of the waveform being a function of the DC error input applied on line 52 taken from the error detection circuit. Due to the ramp voltage generated during track playback, an end-of-scan trigger pulse from a conventional trigger pulse generation circuit (not shown) triggers pulse generator 56 and is applied to the input of integrator 50 via adder 64 and line 66. output pulses are generated at the end of track playback. Since the output pulse from pulse generator 56 is a very short duration negative pulse, it has the effect of resetting the output voltage to a level that will produce the desired displacement of the transducer head at the second track regeneration position. As the integrator output increases during the second playback of track A, the end of the scan trigger circuit terminates at the pulse generator 56 at some point near the end of the second playback.
Give a trigger pulse to. However, forward tape advance level detector 68 continuously monitors the instantaneous voltage at the output of integrator 50 and indicates that the instantaneous voltage is approximately zero.
An inhibit signal is generated on line 70 which inhibits pulse generator 56 whenever . Therefore, the second playback of track A is nearing its end,
When the end-of-scan trigger pulse is applied to trigger the pulse generator, the detector detects that the output voltage is below a value of approximately zero and generates an inhibit signal on line 70, as shown in Figure 7a. do. The pulse generator is inhibited and the integrator 50 is not reset and continues to operate, actually following track B as the first playback. Since the voltage at the integrator output near the end of the first playback is positive, forward tape advance level detector 68 does not inhibit the pulse generator and a reset pulse is generated.

When the tape is fed in the reverse direction to provide the effect of reverse motion during playback, the transducer head must be reset to play the temporally preceding track as described above. When slow motion reverse playback is performed at 1/2 speed, the circuit of FIG. 6, for example, produces the voltage output waveform shown in FIG. 7b. A comparison of the waveform of FIG. 7b and the displacement pattern of FIG. 5i shows a mirror image or inversion pattern, as is the case with those shown in FIGS. 5b and 7a. As the tape follows track A during the first playback, the instantaneous voltage near the end of the scan is 7b.
As shown, above zero, pulse generator 56 generates a reset pulse which has the effect of resetting the transducer head by one center spacing of 8.7 mils. The converting head performs a second scan, i.e. playback, to track A.
, the lamp voltage approaches a higher level V ₂ and the higher voltage is detected by the reverse tape advance level detector 72 . When the end-of-scan trigger pulse is generated, pulse generators 56 and 60
is operational because level detector 72 does not provide an inhibit signal on line 74. The output pulses of pulse generators 56 and 60 are summed by a summing circuit 64 and a double amplitude pulse is sent to line 66.
is applied to the input of integrator 50 to reset the conversion head to move a distance equal to twice the track center spacing, or approximately 17.4 mils, in the illustrated embodiment. In this way the tracks are played during reverse tape feeding, ie in reverse order, but also in such a way that a slow motion effect can be achieved.

A special schematic circuit diagram that can be used to implement the operation of the circuit shown in the block diagram of FIG. 6 is shown in FIG. This circuit receives a low frequency or DC error signal from the synchronization detection circuit associated with the error detection circuit, which does not form part of the invention.
The integrator 50 has an integrator 2. The error signal is applied via analog switch 80. This switch is a CMOS device that is on when a positive voltage (operator, mode control command) is on line 82 and off otherwise. Its function is to disable this circuit during normal playback. Integrator 50 includes an operational amplifier 82 with an industry standard number in brackets and an adjacent pin number and a feedback capacitor 84 having an output connected to line 54. A forward tape advance level detector 68 is connected to output line 54 via line 86 and resistor 88 to monitor the instantaneous voltage and generate a high output level on line 70 whenever it is about 0 or greater. It has an operational amplifier set to Similarly, the reverse tape feed level detector 72
includes an operational amplifier that monitors the instantaneous output voltage via line 86 and resistor 90, with potentiometer 9 set to a high level, such as approximately 3V.
Compare the output voltage with the voltage present on pin 1, which is adjustable controlled by 2. As the instantaneous output voltage approaches the preset limit, the operational amplifier output voltage appearing on line 74 goes high.

Pulse generators 56 and 60 have monostable multivibrators, or one shots, that are energized when both inputs A and B are high. When each pulse generator is energized, a negative pulse is generated at its respective Q output and applied to the input of integrator 50 via line 66, summer 64 and respective lines 58, 62. The output from each pulse generator is extended to other circuits and is used for time base error correction. Line 76 is connected to input A of both pulse generators and is low when the leading edge of the scan trigger pulse is present. Pulse generator 56 is connected to forward level detector 68 by line 70 connected to the B input. Pulse generator 56 is energized by the magnetic transition on line 76 when input B is at a high logic level, so that whenever level detector 68 detects a voltage below a value of approximately zero, pulse generator 56 is prohibited. Similarly, pulse generator 60 is low whenever the monitored voltage on line 74 connecting the B input and the output of inverting level detector 72 is below a preset value of, for example, about 3V. The pulse generator 60 is therefore inhibited at all times except when the lamp voltage approaches a higher level representing the deflection limit of the transducing head in that direction. When this occurs, both pulse generators generate double amplitude pulses that reset the conversion head by a total of two tracks. It can be seen from the output waveforms of FIG. 7b that pulse generator 56 is energized after each track is played, and pulse generator 60 is energized at the end of each second play of a track.

Zener diodes 94 and 96 convert the voltage range of the outputs of level detectors 68 and 72 to a range comparable to pulse generators 56 and 60. Diode 98 is provided to maintain a self-centering feedback voltage at the input of the integrator in a known manner when no signal is applied to the input. The output voltage on line 54 is extended to another summing circuit and the other signal components are connected to movable element 22.
is added because it is applied to the circuit that drives it. Its output voltage is proportional to the deflection produced by the element.

According to another feature of the invention, speed-up or high-speed motion operation is achieved. The circuits shown in Figures 6 and 8 do not achieve high speed motion operation because the ramp voltage from the integrator is inverted relative to that required. However, a suitable level detector and switching circuitry (not shown) to connect it while operating in the fast forward mode is within the scope of the invention. High speed motion effects are achieved by advancing the transducing head in one or more directions while the tape is being advanced at a speed faster than the recording speed. In Figures 5g and 5h, the excursion pattern for high speed motion effects where the tape is fed by a factor of 2 or 3 is shown along with the repositioning of the transducer head at the end of each track. For double fast motion, each second track is skipped during playback and the transducer head is moved approximately 8.7 mils, or one track interval. The deflection of the transducer head that occurs during slow motion or still frame mode operation is in the opposite direction. 3 shown in Figure 5h.
For double-speed motion, the conversion head must be caused to skip two tracks so that each third track is played back when operating at this speed.
This results in a repositioning distance of 17.4 mils. The three-times high-speed motion shown in Figure 5 has a total of two center-to-center displacements,
That is, with a displacement of approximately 17.4 mils, the high speed motion requires additional deflection that must match the design and operation of the movable element 22 for speed and its full range of motion.

According to yet another feature of the invention, the device is adapted to operate in a surveillance mode as well as in a skip frame mode of operation. Figure 5f shows the displacement pattern for the transducer head when the apparatus is operating in the supervisory mode, and information is recorded at a much slower feed rate than during normal recording. Therefore, in the displacement pattern shown in Figure 5f, the tape feeding speed is 1/60 of the normal speed.
The switching circuit records each 16th frame. The video recorder scanner records only one scan per second and is triggered to ignore the next 59 scans resulting in a synchronized recording format with a helical angle approximating the stop motion playback mode. Each 16th frame recording represents only a special case; more or less than 59 frames may be skipped. In other words,
The longitudinal tape feed rate during recording does not significantly change the helical angle produced by stationary or stopped motions.
During normal speed playback, tracking errors occur in the same way as they occur in the stop mode of operation for signals recorded at normal speed. The tracking pattern shown in Figure 5f indicates that the converting head follows the track accurately during playback and repositions the converting head at the beginning of the next track by moving downward as shown. The supervisory mode of operation causes the television field information of each second track to be recorded, saving a large amount of magnetic tape and providing good recording of a series of information fields whose operation can be approximated. Furthermore, the quality of the recorded signal is not reduced by tracking errors and crossovers during playback.

For skip fields, particularly a skip 1 field system having a displacement motion pattern as shown in FIG. 5a, every other field is recorded and the other fields are ignored. Recording and playback tape speeds are approximately 1/2 the normal forward speed when fields are not skipped. Since the recording and playback speeds are the same (at a lower speed), the track angle is approximately the same during recording and playback since no transverse movement of the transducer head is required during track playback. However, during playback, a continuous 60 hertz information rate is required, requiring each track to be repeated twice. Thus, track A is regenerated once by moving the conversion head a distance of approximately 4.35 mils at the end of its first regeneration. That distance puts the head in the correct position for repeated playback of track A. At the end of the second playback, it is necessary to advance the conversion head by moving it downwardly, transversely to the first playback of track B.
The repositioning of the transducer head after each track playback will ensure that the tape is 1/2 the recording speed compared to the recorded track speed for other modes of operation.
is moved, so it only requires 1/2 the displacement required for the 8.7 mils shown in the other displacement patterns for 1 center distance. By utilizing the playback positioning of the conversion head after each track playback, a single head can achieve the same effect as two heads produced by similar skip field operations in prior art systems. Also, although a displacement pattern for a skip one field system is shown, the invention can be used to skip more than one field (each field occupying one track). Thus, each nth field is recorded on a track, intermediate fields are ignored, the tape is driven at 1/n of the normal forward speed during recording and playback, and the transducer head is driven at n=2 as described above.
is adjusted stepwise in a manner similar to that shown for the case. If each nth field is recorded, it is necessary to play each field n times, in other words, play each track and play it n-1 times.

This embodiment represents a closed loop system in that the error correction signal used to keep the conversion head on track during track playback receives continuously updated information from the error detection circuit. Due to closed loop operation, the transducer head follows the track accurately regardless of the feed speed or direction being used. The circuitry is adapted to automatically decide whether to advance the transducer head to the next adjacent track during a forward motion or to the previous track during a backward tape motion, thereby eliminating the traditional ``infinite limit'' effect. An adjustable capstan drive circuit is available. For example, a potentiometer controller such as a "Joy Stakes Controller" can be used to control a tape advance capstan driver if an operator wants to change the slow motion speed for instantaneous playback of a sports game. I can do it. Furthermore, the automatic determination feature of the error detection circuitry allows the operator to advance the tape at any speed, for example field by field with long pauses, by manually spinning the reel.

Although the illustrated embodiment was a closed loop system, the invention is also applicable to open loop devices. In an open loop system, the integrator 50 does not receive a low frequency or DC error signal from the error detection circuit, but is connected to the integrator input and adjusted to provide a voltage waveform associated with the desired tracking or special motion effect. Use an adjustable direct current source. Such an open-loop system allows the tape speed to be adjusted such that the tape is run at the exact speed expected by a programming device that generates a voltage waveform that produces an appropriate displacement pattern similar to that shown in FIG. Requires very careful control.

From the above description, it can be seen that the present invention achieves a modified time base effect in the technique of recording and reproducing information signals on a medium. Regarding this,
The invention is particularly suitable for creating special operations and other effects in the field of video recording without compromising the quality of the signal being reproduced from the recording medium.
Furthermore, the present invention is particularly useful in spiral-wound video tape recorders since special motion effects such as slow motion, still frame or stop motion and fast motion effects can be achieved without compromising the video signal extracted from the magnetic tape. suitable for The system accurately follows tracks during playback and automatically detects the position of the playback head near the end of the track and determines whether to advance the conversion head to the next non-adjacent track. Because the present invention automatically determines near the end of a track's playback, the tape being fed in slow motion mode can be moved at any speed, thereby allowing infinitely adjustable slow motion playback. The high speed motion effect is limited only by the deflection range of the transducer head, and 2-3 times the "normal motion speed" is possible.

[Brief explanation of drawings]

1 is a perspective view of an omega-wound helical scanning drum used in the present invention, FIG. 2 is a plan view of the scanning drum shown in FIG. 1, and FIG. 3 is an enlarged view of a magnetic tape having tracks A-F. 4 is a plan view of the omega-wound helical recorder; FIG. 5a is a diagram of the displacement pattern for the transducer head when operating in skip field mode; FIG. 5b; FIG. 5c; Figure 5d is a displacement pattern diagram for the transducer head when operating in slow motion mode, Figure 5e is a displacement pattern diagram for the transducer head operating in still frame or stop mode of operation, and Figure 5f is a diagram of the displacement pattern for the transducer head operating in monitor mode. Figures 5g and 5h are displacement pattern diagrams for the converting head when operating in high speed motion mode, Figures 5i and 5i.
Figures 5j and 5j are diagrams of displacement patterns for the transducer head when operating in reverse slow motion and normal speed, Figure 6 is a block diagram showing the electrical circuitry associated with the apparatus embodying the invention, and Figure 7a The figure is number 6
7b is a voltage output waveform diagram of the circuit shown in FIG. 6, and FIG. 8 is a circuit diagram for implementing the circuit of FIG. 6. 10: Video head scanning drum, 20: Video conversion head, 22: Movable support element, 24: Cantilever support, 50: Integrator, 56, 60: Pulse generator, 64: Adder, 68: Front level detector.

Claims (1)

[Scope of Claims] 1. An information signal transfer device for transferring information signals on a magnetic tape that is fed at a selected speed different from the normal recording and playback speed, wherein the tape is at least one rotatable transducer that scans the tape to transfer information signals over a plurality of closely parallel tracks extending at an angle, the transducer extending along the length of the track. mounted on the rotatable member by a holder carrying a transducer capable of being laterally deflected in both directions with respect to the transverse direction, the holder being configured to deflect the transducer in both directions as the tape is fed at the selected speed; the holder is coupled to a controller for generating a control signal for laterally deflecting the transducer, the control signal being a composite signal having first and second signal components applied to the holder; The first signal component is arranged between the selected speed and the normal speed to cause the transducer to laterally deflect the transducer so that the holder follows a track of interest during the transfer of information signals on the tape. the second signal component is a ramp signal having a slope according to the difference in the retention period, and the second signal component changes successively during the period to begin tracking the track on which the information signal is to be transferred following the period. the first signal component generated by the controller has an amplitude different from the amplitude of the second signal component such that the tape is positioned in the selected position. the transducer follows the track of interest during each period of transmission of the information signal and, following each period of said period, begins to follow the track on which the information signal is to be transmitted. An information signal transfer device characterized in that the information signal transfer device is positioned as follows. 2. In an information signal transfer device for transferring information signals with respect to a magnetic tape that is fed at a selected speed different from the normal recording and playback speed, said tape has a plurality of tapes extending at an angle with respect to its length. At least one rotatable transducer is sent along a helical path to scan the tape so as to transfer information signals on closely parallel tracks, the transducer being oriented relative to the length of the track. mounted on the rotatable member by a holder holding a transversely deflectable transducer in both directions, said holder being coupled to a controller for controlling the transfer of information signals on said tape. during which the holder generates a first control signal for laterally deflecting the transducer to position the transducer to follow a track, and the controller is configured to perform a first control signal after the transfer of the track information signal. ,
said holder generates a second control signal for transversely positioning said transducer to position said transducer at a starting position of a track to be subsequently scanned according to said selected speed; (a) means for detecting the lateral position of the transducer at the end of the transfer of information signals regarding the tape; and (b) means for detecting the lateral position of the transducer at the end of the transfer of information signals regarding the tape; and means for responding to the detected lateral position so as to generate or not generate the second control signal depending on whether the detected lateral position is reached or not. information signal transfer device.