JPH02231884A - Helical scan system magnetic tape recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the function and performance of special reproducing by fitting one movable head for special reproducing movably to a rotary drum in an axial direction, providing a field memory to store a signal by one field, satisfactorily coupling and using the movable head and field memory. CONSTITUTION:For example, when a movable head 3 exactly traces a track A1 of the odd numbered field, Y and C signals demodulated by Y and C signal demodulation circuits 13a and 13b go to be composite video signals. The Y signal and a color difference signal, which are outputted from clamp circuits 103 and 111, are respectively converted into digital signals by an A/D conversion circuit 104, written and stored to a field memory 105. Since there is no head to execute tracing during the next odd numbered field, information stored in the memory 105 are read and sent. Accordingly, since signals A1 and B3 of the odd and even numbered fields are sent as the wholly same output video signal, there is no flicker at all and the reproduced picture of high quality can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a movable head movable in the axial direction of a rotating drum and a field memory that stores signals for one field in addition to a normal recording/reproducing head. The present invention relates to a helical scan type magnetic tape recording and reproducing apparatus.

[Prior Art] Conventionally known helical scan type magnetic tape reproducing devices of this type include those equipped with a movable head for special reproduction and those equipped with a field memory.

FIG. 5 is a perspective view showing a rotating drum device in a conventional magnetic tape recording/reproducing device equipped with a movable head for special playback. In the same figure, (6) is a rotating drum driven by a drum motor (6M). be rotated. (1), (2)
is a video head for normal recording and playback (hereinafter referred to as a recording/playback head).
are installed at a phase angle of , and have different azimuth angles from each other.

(3) and (4) are video heads for special playback (hereinafter referred to as movable heads), which are mounted on the rotating drum (6).
For example, pymorph-type piezoelectric elements (5a) and (5b) (hereinafter referred to as pymorph plates) mounted at a phase angle of 0°C are attached to the free tips of the piezoelectric elements so as to be movable in the axial direction of the rotating drum (8). attached and have different azimuth angles. These movable heads (3). (4) As clearly shown in FIG. Due to the deflection in the x-y direction, it moves while remaining in contact with the magnetic tape (8).

Figure 7 shows the bimorph plate (5a). This explains the structure and operating principle of the bimorph plate (5b).
). (5b) is indicated by the arrow (A) in the figure. (B) -c
Two piezoelectric elements (5c) and (5d) with the orientation shown
It has a structure in which electrodes (5e), (5f),
When a driving voltage (e) is applied through (5g), the element (5c) whose orientation is in the forward direction (A) contracts, and the element (5c) whose orientation is in the forward direction (A) contracts, and in the reverse direction (B
) is elongated, so when one end is fixed as shown in FIG. 6, the other end is deflected and deformed by an amount corresponding to the polarity and level of the driving voltage (e). This deflection causes the movable heads (3) and (4
) is configured to move in the axial direction of the rotating drum (6) and to scan seven tracks of the magnetic tape (8) by appropriately setting the waveform of the driving voltage (e).

FIG. 8 is a diagram showing a 1-rack pattern on the magnetic tape (8). During recording, the magnetic tape (8) runs in the direction of arrow (F) and is sequentially moved by the recording/reproducing heads (1) and (2). The recorded tracks are (At), (Bl) . (A2) ,(
B2). (A3), (B3). (A4)... is shown. Here, track (AI). (A2) ,
(A3) ... and the truck (Bl). (B2). (
B3)... is recorded at a different azimuth.

Next, the operation of the above configuration will be explained.

As an example of the special playback mode, when playing at 5x speed, the movable heads (3) and (4) are replaced by the bimorph plate (5a),
The scanning trajectories when not driven in (5b) are as shown by dotted lines (Ll), (L2), and (L3) in FIG. Then, the azimuth angle of one movable head (3) is A
If the azimuth of the track is the same, the signals reproduced by this movable head (3) are the tracks (AI), (A2), (
If only the shaded part of A3) is sharp, and if the azimuth angle of the other movable head (4) is the same as the azimuth of track B, then the signal reproduced by this movable head (page 4) will be the same as that of track (4). Tracks included in L2) (
Only the diagonally shaded portions of B3), (B4), and (B5) are present, and noise permeation occurs on the playback screen at the connecting portions between them. In order to eliminate the occurrence of such noise bars, playback can be performed by scanning the movable head (3) along the track (A1) and the movable head (4) along the track (B3). . To do this, during one field period when one movable head page 3) is in contact with the magnetic tape (8) and is being reproduced, the movable head (3) must be moved in the width direction of the track as shown by the arrow (a). Similarly, in the next field period, if the movable head (4) is moved in the direction of arrow (b) by four track pitches, the movable head (3) will move to the track (
AI) and the movable head (4) scans the track (B3).

Track (AI), (B3) as shown below-12
, (A8)..., the bimorph plate (
By driving 5a) and (5b), a noise-free 5x speed reproduction signal can be obtained.

FIG. 9 is a block diagram showing the configuration of a reproducing system of a conventional magnetic tape recording/reproducing apparatus. In the figure, (10) is a rotary transformer, (11) is a normal reproduction head amplifier, and the upper recording/reproducing head +), (2) to amplify the minute level reproduced FM signal picked up by (2). (36) is a timing generator, (13) is a reproduction signal processing circuit, and the reproduction FM signal is transmitted to the timing generator (36).
) is switched by the output signal from the switch (12
) is input to the reproduction signal processing circuit (13) and demodulated into a video signal (V).

Reference numeral (14) denotes a search head amplifier, which amplifies minute level reproduction FM signals picked up by the movable heads (3) and (4) when performing, for example, 5x speed reproduction. (15) is an envelope detection circuit that detects the envelope of the reproduced FM signal, and (16) is a microcomputer that controls the driving voltage signal (hereinafter referred to as search correction signal) of the bimorph plates (5a) and (5b) during search. ) is output. (17) is an FG counter that counts the capstan FG signal (hereinafter referred to as CP●FG signal) and is reset by a control signal (hereinafter referred to as CTL signal).

(18) is a comparator, (18) is a floating counter, (20) is a speed counter, (2 1a),
(2 lb) is the output counter, (22a), (22b
) is an adder, (23a) . (23b) is a low-pass filter (hereinafter referred to as LPF). (24a), (24
b) is a driving high-voltage amplifier that drives the pymorph plates (5a) and (5b). (25) is a synchronization separation circuit, which receives the vertical synchronization signal (
V-SYNC. ) and operate the microcomputer (16) based on this.

Next, the operation of the configuration shown in FIG. 9 will be explained.

The conventional example shown in FIG. 9 includes a CTL signal, CP/FG signal, and head switch signal (hereinafter referred to as HSW signal).
are input to the bimorph board (5a). (5b)
The signal waveform of the drive voltage (e) is determined. That is, the CPΦFG signal is counted by the FG counter (17) reset by the CTL signal,
Supplied to a comparator (18). This comparator (
The threshold value of 18) is determined by the speed counter (20), and this threshold value is preset in the floating counter (19) by the output of the comparator (18).

The output signal of this floating counter (19) is supplied as a preset value to the output counters (21a) and (2lb). Output counter (2 1a). (2lb)
is an FG counter that presets the preset value input from the floating counter (19) at the rising or falling edge of the HSW signal, and the output counter (21a)
．． (2lb) output signal, an envelope detection circuit (l
Based on the envelope detection signal inputted from the adder (22a). (
22b).

Then, these adders (22a) . The ripple component of the output signal of (22b) is L P F (23a), (2
3b), high voltage amplifier (24a), (2
4b), the bimorph plate (5a)
．． (5b) to move the movable head (3). (4) to perform a predetermined automatic tracking operation.

FIG. 10 is a block diagram showing the configuration of the playback system of another conventional magnetic tape recording and playback device equipped with a field memory. The Y/C separation circuit (103) is a clamp circuit that separates the Y/C separation circuit (hereinafter referred to as "C signal") into a chroma signal (hereinafter referred to as "C signal").
The Y signal separated by the analog switch (101)
2) to maintain that black level. (10
4) is an A/D conversion circuit, which includes the above-mentioned clamp circuit (103).
The analog Y signal output from the converter is converted into a digital signal.

(109) is a decoder, and the above Y/C separation circuit (101
) is input, and the color difference signal (R −
Y), (B-Y). (111) is a clamp circuit, which is a color difference signal (
Clamp R-Y) and (B-Y). (112) is A
The /D conversion circuit converts the analog color difference signals (R-Y) and (B-Y) output from the clamp circuit (III) into digital signals.

(105) is a field memory, and this field memory (105) is composed of three IMbit dynamic random access memories, and the A/D conversion circuit (
Digital Y output from 104) and (+12)
The signals and digital color difference signals are written sequentially. (
10? ) is a memory control gate array that controls the operation of the field memory (+05). (108
) is a memory control microcomputer that controls the operation timing of the field memory (105) and memory control gate array (10?).

(106) and (113). (114) are each D
The /A conversion circuit converts the digital Y signal q and the digital color difference signal read out from the field memory (105) at different timings into analog signals, respectively. (115) is an encoder that encodes the two analog color difference signals output from the D/A conversion circuits (+13) and (114) into a C signal.

(118) is the mixer C (hereinafter referred to as MIX), and the above D
The analog Y signal output from the /A converter (toe) and the analog C signal output from the encoder (115) are mixed. (117) is a switch for achieving a picture-in-picture function, and (11B) is a switch for achieving a stay/slow function.

Next, the operation of the configuration shown in FIG. 10 will be explained.

When a composite video signal is input to the Y/C separation circuit (101), this composite video signal is divided into Y signal and C signal.
Separated into signals. Of these, the Y signal is input to the clamp circuit (103) via the analog switch (to2) to maintain the black level. This clamp circuit (103)
The analog Y signal output from the A/D conversion circuit (10
After being converted into a digital signal in step 4), it is written into the field memory (+05).

On the other hand, the C signal is input to a decoder (109) and converted into two color difference signals (R-Y) and (B-Y), and then passed through an analog switch (110) to a clamp circuit (1
11) and are sequentially input and crushed. The color difference signal output from the clamp circuit (III) is converted into a digital signal by an A/D conversion circuit (112), and then written into a field memory (105).

Next, the digital Y signal and the digital color difference signal written in the field memory (105) are controlled in operation according to a preset sequence by the memory control gate array (10?) and the memory control microcomputer (108). It is read out from the field memory (105) at different timings, and the D/A conversion circuit (1oa) and (113), (
114), each is converted into an analog signal. Of these, the two analog color difference signals output from the D/A conversion circuits (113) and (114) are encoded into the original C signal by the encoder (115), and this C signal and the above Y signal are mixed into the MIX (11B). ) and then output via analog switches (11?) and (118).

That is, in a conventional magnetic tape recording/reproducing apparatus equipped with a field memory (105), the memory control array (107) and the memory control microcomputer (108) are operated to configure various algorithms. , still, slow, picture-in-picture, multi-screen, strobe, realization, and other special screen functions have been achieved.

[Problems to be Solved by the Invention] The conventional helical scan type magnetic tape recording and reproducing apparatuses configured as described above, both those equipped with a movable head and those equipped with a field memory, have a special reproduction function. At the same time, the functional parts of the movable head and the functional parts of the field memory are completely independent from each other. That is, those with a movable head are configured to handle the still, slow mode, and speed search functions in an analog manner, and those with field memory are configured to handle still, picture-in-picture, strobe, and multi-screen functions. It is configured to digitally process functions such as, and there is no connection between the two (when the functional part of the movable head was operating, the field memory was not operating. Both the movable head and field memory are extremely expensive, and configuring them to operate independently is cost-effective.
I didn't like it in terms of masturbation.

This invention was made to solve the above-mentioned problems, and it is a helical scan magnetic tape recording and reproducing system that can improve special playback functions and performance by skillfully combining a movable head and a field memory. The purpose is to provide equipment.

[A Thousand Steps to Solve the Problem] The helical scan magnetic tape recording and reproducing apparatus according to the present invention has one movable head for special reproduction that can be moved in the axial direction of the rotating drum, and a A field memory is provided to store the signals of
During normal recording and playback, the signal for 1 field is stored in the field memory, and during special playback in which the movable head is moved, the signal for 1 field reproduced by the movable head is stored in the field memory, and the next field is stored in the field memory. It is characterized by being configured to complement each other.

[Function] According to the present invention, during normal playback or recording, the normal recording/playback head is operated and the field memory is operated to perform still image processing functions such as strobe, multi-screen, and realization. realizable. Also, during special playback such as speed search, one movable head plays back one field's worth of signals, and the next field is complemented with the signal stored in the field memory, making noiseless special playback possible. can.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a perspective view showing a rotating drum device in a helical scan type magnetic tape recording and reproducing apparatus according to an embodiment of the present invention. In the same figure, there is one difference from the conventional example shown in FIG. Since only the movable head (3) is attached and the movable head (4) and bimorph plate (5b) shown in Fig. 5 are omitted, the other configurations are the same as in Fig. 5, so the same reference numerals are used. , and their explanation will be omitted.

Further, the positional relationship between the movable head (3), the rotating drum (6), the fixed drum (7), and the magnetic tape (8) is as shown in FIG. The principle of operation of the bimorph plate (5a) that is driven and displaced in the axial direction is as shown in FIG. 7, and therefore, illustrations thereof will be omitted.

FIG. 2 is a block diagram showing the overall configuration of a reproducing system of a magnetic tape recording/reproducing apparatus equipped with a rotating drum device as described above, and in the same figure, (1) to (3). (5a),
(10) ~(12), (l4), (15), (25)
, (36) have the same configuration as the conventional example shown in FIG. 9, and (101). (103) ~ (10EI) .
Since (109) to (+15) and (+17) have the same configuration as the conventional example shown in FIG. 10, they are given the same reference numerals and their explanation will be omitted. Further, the memory control gate array (107) and the memory control microcomputer (10B) are approximately the same scale and have the same basic functions as those in FIG. 10, but are slightly different in terms of algorithm.

In FIG. 2, (3l) is an A/D conversion circuit that converts the output voltage from the envelope detection circuit (15) into a digital signal. (32) is a microcomputer that sends digital data signals that control the movable head page 3) to the high voltage amplifier (24) that drives the bimorph board (5a) using respective timing input signals and mode output signals. (23). This microcomputer (32) generates a scanning signal basic waveform R O M (32a) and performs tilt correction R O
M (32b), an optimum track movement ROM (32c), a hill climbing correction ROM (32d), and a swingback signal waveform generation ROM (32e). (33
a) and (33b) are D/A conversion circuits that convert output signals corresponding to the respective outputs of the microcomputer (32) into analog signals. (34) is an adder, and the D/A conversion circuit (33a). Add the two analog signals output from (33b). (35) is a sequence control circuit that performs sequence control in various playback modes, and is a controller (35) that outputs operation signals in response to various input signals to the delay circuit (35a) and the timing generator (38). Below, CONT
) (35b).

(l3) is a reproduction signal processing circuit, which includes a Y signal demodulation circuit (13a) that demodulates the Y signal converted into an FM signal and a C signal demodulation circuit (+3
b) Consists of. (37) is an antenna for receiving television radio signals, (38) is a tuner, and (38) is a switch for switching and selecting two video signals. (41
) is an interlocking switch, (42) is a burst gate circuit that picks up the burst signal from the C signal, and (43) is a P
The LL circuit locks the frequency and phase with the burst signal output from the burst gate circuit (42), and locks the frequency and phase of the burst signal output from the burst gate circuit (42).
? )． Memory control microcomputer (1
08) and a clock signal for driving the field memory (105). This clock signal is a 14 MHz clock signal obtained by multiplying the carrier wave of the demodulated C signal by 4.

(44) is a MIX that mixes Y signal and C signal, (4B)
field memory (105), memory control gate array (107), microcomputer Bo
a child screen insertion circuit (47
) is an output selection switch that selects any one of three types of screen video signals: analog screen, sub screen, and digital processing screen.

(45) is a YC signal MIX, (45a) is a Y signal output terminal, (45b) is a C signal output terminal, and (45c) is a composite video signal (y+c) output terminal.

Next, the operation during speed search with the above configuration will be explained with reference to the signal waveform diagram in FIG. 3 and the explanatory diagram of the locus of the movable head in FIG. 4.

71. to the sequence control circuit (35). 3
When the fixed head switching flip-flop signal (FF) shown in FIG. 3(a) is input, the movable head switching flip-flop signal (MVFF) shown in FIG. 3(b) is delayed by a predetermined amount in the delay circuit (35a). is input to the microcomputer (32).

Now, as shown in Fig. 4, when performing 5x forward search playback, when the command is issued from the sequence control circuit (35), the microcomputer (32
) sends out the stored contents of the scanning signal basic waveform generation ROM (32a) which specifies the ideal value of the scanning pattern of the 5x speed movable head (3) among the built-in ROMs (32a) to (32e). This scanning signal basic waveform generation R O
The waveform signal sent from M (32a) is sent to the D/A conversion circuit (33a). Adder (34), LPF (23),
A high voltage is applied to the bimorph plate (5a) via the high voltage amplifier 7' (24) to determine the basic position at which the movable head (3) scans on the track (A1) shown in FIG.

This operation corresponds to the operation shown by the broken line in part A in FIG. 3(C).

At this time, the track (A1) played back by the movable head (3)
) is envelope-detected by an envelope detection circuit (15), converted to a digital signal by an A/D conversion circuit (31), and the converted digital signal (S) is serially sent to the microcomputer ( 32
). This microcomputer (32) sequentially compares and calculates the envelope detection signal (S) and the fundamental waveform of the selected scanning signal at each step, and calculates the slope correction R O M (32) in which various correction values are prepared.
b) Select the optimal slope correction value from among (about 32 types are required), and add this slope correction signal to the adder (34 types are required).
) is used to drive the bimorph plate (5a). As a result, the inclination angle of the scanning locus of the movable head (3) is corrected as indicated by the arrow A in FIG. 3(c). This correction operation corresponds to the correction of the head movement amount indicated by the arrow (a) in FIG. 4.

By the above operation, the fR. ! r
The scanning locus of the corner and the movable head page 3) coincide as shown in section A in FIG. 3(c).

Next, in order to obtain the optimal result during the 5x forward search, the optimal track movement signal for selecting the preselected track is converted into the optimal track movement R O M (32
The movable head (3) scans the optimum track by reading out the drive signal from the drive signal (c) and adding this movement signal to the bimorph plate (5a). In this case as well, the envelope detection signal (S) is applied to the microcomputer (32) in the same way as above, and the optimum track is selected from this level.

With the above operation, the head (3) can move almost on the optimal track.
In addition, the best position within the optimal track, that is, the envelope signal (S
), a so-called hill-climbing correction is applied in which the movable head (3) is displaced parallel to the scanning locus in order to track the position where the level of the movable head (3) reaches its maximum value. This operation is performed by the reproduced signal processing circuit (l3
) and separated by the synchronization separation circuit (25), the hill-climbing correction R O M (32d
) to offset the serial envelope detection signal (
S) is set to the maximum value.

This operation corresponds to the operation shown by the broken line at the mouth of FIG. 3(C), and in FIG. 4, it is necessary to accurately follow the X point and scan the center line of the recording track during the l field period. This corresponds to making fine adjustments perpendicular to the video track.

Next, when the movable head (3) finishes scanning the magnetic tape surface, the movable head (3) rotates in the air for the next half rotation without contacting the magnetic tape. The behavior of the movable head (3) during this field period is based on the envelope signal waveform of the previous traveling field period, and the swing-back signal waveform generation R OM (
32e) Select the optimal one from among (about 5 types are required) and send it to the D/A conversion circuit (33a). The waveform of this return signal is as shown in part C of FIG. 3(c). If an inappropriate reversal signal waveform is selected, as shown by the dotted line in part 8 of FIG. will occur.

In this way, when the movable head (3) is driven during a half-rotation of the drum according to the swing-back signal waveform of the swing-back signal waveform generation R O M (32e) prepared in advance, the third
As shown by the solid line in part C of the figure (C), continuous and smooth driving is performed, and a stable noise-free 5x search signal is obtained without generating noise.

The processing of signals during the even field period when the movable head (3) finishes scanning the magnetic tape surface during the odd field period and rotates in the air will be described.

As shown in FIG. 1, since only one movable head (3) is provided, during the even field period when the movable head (3) is rotating in the air, the signal of the previous odd field is transmitted to the field. This will be stored in the memory (105) and sent out.

To explain this operation in more detail, (L1
), that is, when the movable head (3) accurately traces the odd field track (A1), the Y signal demodulation circuit (13a) and the C signal in FIG. The Y signal and C signal demodulated by the demodulation circuit (+3b) become a composite video signal. In other words, the Y signal that has passed through the analog switch (41) is transferred to the clamp circuit (10) to remove errors caused by DC fluctuations.
3), the C signal is converted into color difference signals (B-Y) (R-Y) by the decoder (109), and then sequentially switched in time by the analog switch (+10) and sent to the clamp circuit (111), respectively. It is input and crushed. These clamp circuits (103). (111)
Y signal and color difference signal (B-Y) (R
- Y) are A/D conversion circuits (104) and (11), respectively.
2), converted into a digital signal, and written and stored in the field memory (105).

Since there is no head to trace during the next odd field period, the information stored in the field memory (105) is read out and sent out. This field memory (105
) The digital signal sent from the D/A conversion circuit (1
0B). (113), (114), where it is converted to an analog signal, and then the analog switch (
117) and composite video output terminal (45c)
will be sent to.

Here, as shown in FIG. 4, the odd field (A1)
Since the signal of the even field (B3) and the signal of the even field (B3) are sent out as exactly the same output video signal, that is, (L1) and (Ll1) are exactly the same, the temporal resolution is inferior, but on the screen Since the same search signal is sent for both odd and even fields, there is no flicker at all, and a high-quality reproduced image can be obtained.

That is, the signal at (Ll) is the analog signal itself picked up by the movable head (3), and during the period of the next field (Lll), the signal at (Ll) is converted into a digital signal and stored in the field memory (+05). This is a signal that was sent out after converting the signal stored in the device into an analog signal.

Next, you can perform image processing functions such as picture-in-picture, strobe, multi-screen, and realization while viewing the television image through the tuner (38) without performing normal playback, recording, or recording/playback operations. Let's discuss the case where

In this case, the above three input signals are sent via the switch (4l), that is, the radio wave reception signal from the antenna (37),
External video input signal from an external video device (not shown), VTR
One of the reproduced signals is selected. After the input signal is selected in this manner, the same operation as in FIG. 10 is performed for both the Y signal and the C signal.

That is, Y for l fields converted into digital signals.
signal, C signal is memory control gate array (10
7) Processing such as thinning and rearranging is performed by the microcomputer (108) to create special still image signals such as strobe, multi-screen, and relaxation. In addition, the signal is time-compressed to create a small screen signal, which is inserted into a part of the playback signal to display a picture-in-picture screen.

Although the above embodiment has been described using a five-times speed search as an example of the operation of the movable head (3), it can be used for stay and slow operations in almost the same way.

Furthermore, the capacity of the field memory (105) is as follows:
8 bit, 14 MHz, 2 Mbit or more is desirable in pursuit of high image quality, but 6 bit, 10 MHz, I
It may be configured to have a capacity of Mbit.

Further, regarding the drive of the movable head (3), although the case where a bimorph type piezoelectric element was used in the above embodiment was described, the present invention is not limited to this, and the movable head (3) may be driven by a movable coil.

[Effects of the Invention] As described above, according to the present invention, two normal recording and reproducing heads, one special reproducing movable head, and a field memory are skillfully combined and used, so that recording and normal reproducing can be easily performed. At times, it is possible to perform special image processing functions such as still images, strobes, multi-screens, and realization, and during special playback, one field is complemented with the signal of the previous field, resulting in a noiseless and good image. A special playback function can be demonstrated. Therefore, the effective utilization rate of the field memory can be increased, and the special playback function and performance can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a rotating drum device in a helical scan type magnetic tape recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of the overall configuration, and FIG. 3 is a signal waveform for explaining the operation. 4 is a trajectory diagram of the movable head on the magnetic tape, FIG. 5 is a perspective view showing a rotating drum device in a conventional helical scan type magnetic tape recording/reproducing device, and FIG. 6 is a diagram showing the main parts of FIG. 5. An enlarged sectional view, FIG. 7 is an explanatory diagram of the structure and operating principle of the bimorph plate, FIG. 8 is a diagram of the track pattern on the magnetic tape and the locus of the movable head, and FIG. 9 is a conventional magnetic tape recording with a movable head. FIG. 10 is a block diagram showing the configuration of a reproducing system of a conventional magnetic tape recording/reproducing apparatus equipped with a field memory. (1). (2)...recording/reproducing head, (3)...movable head, (8)...rotating drum. (32)...Movable head control microcomputer, (105)...
Field memory (107)...Memory control gate array (108)...Memory control microcomputer. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A rotating drum, two normal recording/playback heads attached to the rotating drum at different azimuth angles, and one special playback movable head attached to the rotating drum so as to be movable in its axial direction. It is equipped with a head, a drive mechanism that moves the movable head in the axial direction of the rotating drum, and a field memory that stores one field's worth of signals, and during normal recording or playback, one field's worth of signals is stored in the field memory. Further, during special playback in which the movable head is moved, one field worth of signals reproduced by the movable head is stored in the field memory to complement the next field. Helical scan magnetic tape recording and reproducing device.