JPH04285784A - Rotary head type reproducing device - Google Patents

Abstract

PURPOSE:To decide a tape traveling direction even at the time of traveling a tape at low speed without newly adding a circuit construction by detecting the tape traveling direction by means of an identification number within the (m) pieces of tracks. CONSTITUTION:Segment numbers 1, 2, 3 and 4 are assigned to four tracks in sequence at the time of recording and when the segment numbers are detected as '1, 2, 3, 4, 1, 2, 3, 4', it is judged that a magnetic tape 721 is traveling in a normal direction. When the segment numbers are detected as '4 1', an advance by one frame is judged, a time code is added by '+1' and displayed on a display device 777. On the other hand, when the segment numbers are detected as '4, 3, 2, 1, 4, 3, 2, 1', it is judged that the tape is traveling in a reverse direction. By repeating such procedure, the tape traveling direction can be correctly decided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type reproducing apparatus, and more particularly to a rotary head type reproducing apparatus for reproducing video signals from a tape-shaped recording medium.

0002

[Prior Art] Conventionally, VTR (video tape recorder)
There is a segment method as one of the signal recording methods. In this method, conventional home VTRs have 1 field and 1 field.
In other words, by dividing the signal recorded on two tracks per frame into a larger number of tracks and recording the signal, higher quality images can be recorded and reproduced.

An example of a conventional image recording and reproducing apparatus using this segment method will be described below with reference to FIGS. 3 to 7.

FIG. 3 shows a conventional VTR using the segment recording method.
An example of the circuit configuration is shown below. During recording, the input terminal 201
A synchronization separation circuit 203 separates the synchronization signal from the input video signal, and the A/D converter 205 converts the video signal into a digital signal of a predetermined bit rate. In the next stage signal processing unit 207, the digital signal is temporarily stored in its internal memory and data is rearranged for segment recording.Then, it is converted back to an analog signal in the D/A converter 209 and used in this method. Appropriate modulation is performed in modulator 211, and the modulated signal is fed through recording amplifier 213 to rotary head 219 on rotary cylinder 217 and recorded on magnetic tape 211.

On the other hand, during reproduction, a recording signal is picked up from the magnetic tape 221 by the rotary head 219, this signal is amplified by the reproduction amplifier 225, demodulated by the demodulator 227, and then sent to the A/D converter 229. A by
/D (analog/digital) change, signal processing section 231
Then, the data is rearranged in the opposite direction to that in the recording signal processing unit 207 to form the original data sequence, which is then converted into an analog signal by the D/A converter 233, and a synchronization signal is generated by the synchronization adder 235. The signal is added and output to the output terminal 237 as a video signal.

On the other hand, the synchronization signal separated by the synchronization separator 203 is guided to the system controller 273, and the entire system is synchronized. At the time of recording, a CTL (control) pulse generation circuit 255 generates a CTL signal based on the output timing of this synchronization signal, and the recording amplifier 253 drives the CTL fixed head 249 to write a signal on a longitudinal track on the magnetic tape 221. CTL signal is written. Furthermore, during reproduction, the CTL signal picked up by the CTL fixed head 249 is transferred to the reproduction amplifier 25.
7 and is read by the CTL pulse reading circuit 259,
The signal is sent to the system controller 273 and used to control the system and servo system, and also generates a synchronization signal, which is added by the synchronization adder 235 to the output signal of the D/A converter 233 as a video signal.

Further, during recording, time codes are sequentially generated by the time code generation circuit 269 at the output timing of the above-mentioned synchronization signal, and the fixed head 261 for time codes driven by the recording amplifier 265 outputs the time codes to the magnetic tape 22.
A time code is recorded on one longitudinal track, and this time code is displayed on the display 277. During reproduction, the time code reproduced from the magnetic tape 221 by the time code fixed head 261 is decoded by the time code reading circuit 271 via the reproduction amplifier 267, and displayed on the display 277 via the system controller 273. Ru.

[0008] Switches 215, 251, and 263 are respectively recording/reproducing changeover switches for signal systems. 223 is a drum motor that drives the rotating head 219;
39 is a pinch roller, 241 is a capstan, and 243 is a capstan motor that drives the capstan 241. Capstan FG showing the rotation frequency of the capstan
FG generator (frequency generator) 247 that generates a signal
P which generates a drum PG signal indicating the rotational phase of the drum.
G generator (pulse generator) 245 is capstan F
G signal, drum PG signal to system controller 273
, and servo for tape running and drum rotation is performed via a circuit (not shown). Note that 275 is a keyboard, which is a device through which the user inputs operation commands.

Next, the pattern of signals recorded on the magnetic tape 221 will be explained using FIG. 4. FIG. 4 shows an example of a track pattern on a segment type magnetic tape, where 301 is a helical scan track area by a rotary head, 302 is a time code track where a time code indicating a position on the magnetic tape is recorded;
303 is a CTL track on which a CTL signal for tracking is recorded. CTL pulses are recorded on a CTL track 303 like 304. The time code track 302 and CTL track 303 are linear recording tracks extending in the longitudinal direction of the tape as shown. Here, as an example, a segment recording method is shown in which one frame is recorded on four tracks using two heads. The number shown in the helical scan track area 301 is a segment number, and indicates that four tracks in which signals for one frame are recorded are repeated in order.

Next, an example of how the signals on the actual screen are distributed to these four tracks is shown in FIGS. 5 and 6.
This will be explained using FIG. FIG. 5 shows one screen of an interlaced TV signal, which consists of two fields, A and B, each consisting of a predetermined number of lines. These lines are allocated to each segment according to the rules of FIG. That is, for example, line 1 of field A will be written in segment 1 with the head of channel A, and line 2 of field A will be written in segment 2 with the head of channel B. Therefore, each line is allocated to each segment as shown in FIG.

Segment operations involving these allocations are:
This is made possible by once writing the input/output signals into the memory in the signal processing section 207 in the circuit of FIG. 3, and then performing the reading order in accordance with the rules of FIG.

The recording signal processing unit 207 performs 1 as described above.
When the frame worth of data is allocated, this signal is sent to the magnetic head 219 and recorded on each segment of the magnetic tape 221. Here, a segment identification number code (305 in FIG. 4) is recorded in a part of the track corresponding to each segment in consideration of data reorganization during reproduction. At the time of playback, by playing back the code of the identification number 305 of this segment, the segment number of each track is known, and the data can be reconstructed using this segment number in the signal processing unit 231 for playback. It has become.

[0013] Also, by exchanging data through these processes, it is possible to take measures against burst errors due to dropouts that frequently occur in magnetic media recording.

[0014]

[Problems to be Solved by the Invention] However, in the conventional example described above, when performing slow playback in which the tape is transported at an extremely low speed, the tape speed either decreases extremely or the tape feed speed remains constant. Therefore, it becomes impossible to read the time code recorded on the linear track. Therefore, it becomes impossible to display the time code indicating the tape position.

Conventionally, as a countermeasure for this, unlike a time code signal, it is sufficient to simply detect the presence or absence of a pulse wave for a CTL signal, so an MR head or the like is used to read out the CTL signal from a CTL track. The time code can be obtained by counting and adding the number of CTL pulses apart from the time code position to the time code read just before slow playback starts, or by subtracting it in the case of reverse playback. was. However, even if this countermeasure is implemented, if the vehicle starts running in the opposite direction during slow playback, it will be detected that the vehicle is running in the opposite direction as long as the CTL signal is observed. I couldn't. As a result, a time code different from the original time code is displayed, causing problems such as confusing editing work.

[0016]Also, as a means for detecting reverse running, it is possible to use FG pulses and PG pulses obtained by detecting the rotation of a reel motor, capstan motor, etc. However, for low speed running, both pulses are This method could not be used because the interval was long and reverse running could not be detected quickly. Furthermore, it is also possible to install a timer roller or the like on the tape path and detect the rotation of this timer roller, but this cannot actually be used because it cannot be detected for the same reason as the FG pulse and PG pulse mentioned above. Ta. Furthermore, although it is possible to obtain reversal information from the servo circuit and system controller, it is actually difficult to detect subtle movements such as one frame when the tape is being reversed; Reliable information was difficult to obtain, and in the end it was not possible to use this method because it was delayed in time and the time code could not be counted correctly. Furthermore, since the reversal instruction output from the operator's button operation is also transmitted through the above-mentioned servo circuit and system controller, it cannot be used as a means for detecting reversal driving during low-speed driving, similarly to the above.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide a rotary head type playback device that can appropriately detect reversal of tape running even when the tape is running at a low speed.

[0018]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that a video signal is recorded in m tracks (m is an integer of 2 or more) for one screen, and that each of the m tracks is A device for reproducing the video signal using a rotary head from a tape-shaped recording medium in which an identifiable number is recorded on each track, comprising a detecting means for detecting the reproduction order of the number by the rotary head; The present invention is characterized by comprising a determining means for determining the running direction of the tape-shaped recording medium based on the detection result.

[0019]

[Operation] In the present invention, when reproducing a video signal in which one screen is recorded on m tracks, the detection order of identification numbers in each m tracks recorded in a part of each helical scan track is determined. We have made it possible to monitor and detect reversal of tape running according to changes in the detection order.
You can always know the exact tape running direction even when running at low speed.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a control procedure according to an embodiment of the present invention, and FIG. 2 shows an example of a circuit configuration of an apparatus according to the present invention that executes the control procedure shown in FIG. Here, in FIG. 2, symbols 701 to 777
Each of the constituent elements indicated by 2 corresponds to each of the constituent elements 201 to 277 of the conventional device already explained with reference to FIG. 3, and their functions are almost the same, so a detailed explanation thereof will be omitted. It is assumed that the control procedure in FIG. 1 is stored in advance in the program ROM in the system controller 773 in FIG.

First, the operation of the embodiment of the present invention will be explained with reference to the flowchart in FIG.

[0023] When slow playback of less than 1x speed is selected during playback (steps S1 and S2), first the final value of the time code obtained up to that point is stored in the internal memory (RA).
M) (step S3).

Next, the time code track (30 in FIG.
2) Fixed head for time code (761 in Figure 2)
(Step S4).

Next, the numerical order of the segments recorded in a part (305 in FIG. 4) of each helical scan track (301 in FIG. 4) is detected (step S5). This detection is made possible by the system controller 773 receiving the segment number from the signal processing unit 731 as shown in FIG.

For example, if the segment numbers 1, 2, 3, 4 are assigned in order in a 4-track sequence during recording, the segment numbers 1, 2, 3, 4, 1, 2, 3, 4 are detected. If so, it is determined that the magnetic tape 721 is running in the forward direction (step S6). Subsequently, if 4→1 is detected (step S7), it is determined that the frame has advanced by one, and the time code is incremented by +1 (step S8). This time code is displayed on display 777 in FIG. Next, the process returns to step S1 to determine the playback speed.

On the other hand, the order of segment numbers is 4, 3, 2.
, 1, 4, 3, 2, 1, it is determined that the tape is running in the opposite direction (step S9). Next, when the segment number 1 → 4 is detected (
Step S10), it is determined that the frame has gone back one frame, and the time code is subtracted by -1 (step S11).
. Next, the process returns to step S1 to determine the playback speed.

By repeating the processing steps described above, an accurate time code can be obtained even if the tape running direction changes during slow slow playback.

Note that when the tape running speed is 1x speed or higher, the time code data is used (step S12) and the time code is displayed (step S13) as in the conventional example, and in the stop mode (step S14
), it operates to hold the final value of the time code (step S15). It is assumed that the operations of the components other than those described above are the same as those of the conventional components shown in FIG.

[0030]

Effects of the Invention As explained above, according to the present invention, the running direction of the tape is detected using identification numbers in m tracks without using time code data. Therefore, it is possible to accurately determine the running direction of the tape even when the tape is running at low speed without adding a new circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operating procedure of an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit configuration of a conventional example.

FIG. 4 is a format diagram showing recording patterns on a magnetic tape.

FIG. 5 is an explanatory diagram showing a line configuration of a television signal.

FIG. 6 is an explanatory diagram illustrating the contents of segment recording.

FIG. 7 is an explanatory diagram illustrating the contents of segment recording.

[Explanation of symbols]

719 Rotating magnetic head 721 Magnetic tape 723 Drum motor 731 Signal processing section 749 Fixed head for CTL 773 System controller 761 Fixed head for time code 777 Display device

Claims (2)

[Claims] Claim 1: A tape-like tape in which a video signal is recorded on m tracks (m is an integer of 2 or more) for one screen, and each track has a number that can be identified within the m tracks. In an apparatus for reproducing the video signal from a recording medium using a rotary head, a detecting means for detecting the reproduction order by the rotary head of the number, and a running direction of the tape-shaped recording medium is determined based on the detection result of the detecting means. 1. A rotary head type playback device, characterized in that it is equipped with a determining means. 2. A time code is recorded on the tape-shaped recording medium in its longitudinal direction, and the device includes a fixed head for reproducing the time code, and a time code for following the time code reproduced by the fixed head. 2. The rotary head type reproducing apparatus according to claim 1, further comprising means for generating time information and means for adjusting the time information in accordance with the output of said determining means.