JPS59113543A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable retrieval of a desired video among many video records by changing the running speed of a magnetic tape to a relatively low speed (ordinary playback, pause or stop) when a code signal is reproduced in the high- speed playback state. CONSTITUTION:The 2nd head 18 reproduces the code signal of 1.0MHz recorded in a track A and the 2nd head 19 reproduces the code signal of 1.0MHz recorded in a track B during the period when a magnetic tape is under high-speed reproduction. A filter 35 extracts only the frequency (1.0MHz) of the code signal among the signals reproduced by the heads 18, 19 and applies the same to a control circuit 36. The circuit 36 generates the signal (c) for commanding the change of the running state in response to the application of the prescribed signal in the state in which a passivation signal (b) is applied. A driving circuit 35 for running the tape controls the driving condition of a take-up reel 15 and a capstan 16 so as to change the running state from high-speed reproduction to a pause according to the input of the signal (c).

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a magnetic recording and reproducing device (video tape recorder;
The present invention relates to a VTR (hereinafter referred to as a VTR), and particularly to a VTR improved to have a search function during high-speed playback.

As is well known, in order to record a video signal on a magnetic tape or to reproduce a video signal recorded on a magnetic tape, V
TR is used.

Figure 1A shows the video recording section of a conventional VTR.
FIG. B schematically shows a magnetic tape on which video signals are recorded by a conventional video recording section.

In the figure, a video recording unit 1o includes a head drum 11 rotatably provided at a position where a magnetic tape is run. The head drum 11 is provided with an Iζth head (first heads 12 and 13) for recording or reproducing a video signal at positions separated by an angle (18Q' in the figure) on its circumference.

The magnetic tape 1 wound around the supply reel 14 and the take-up reel 15 is obliquely wound around the head drum 11. A capstan 16 and a pinch roller 17 are provided near the take-up reel 15 with the magnetic tape 1 in between.

By the way, if the VTR is of the VH8 system, the magnetic tape '1
The relationship between the length direction of the head drum 11 and the head drum 11 is such that the right side is tapered and the left side is raised. Therefore, the magnetic pattern of the video signal that can be completely recorded on the magnetic tape 1 is as shown in FIG. 1B. That is, in the VFIS force method, the recorded azimuth of track 2 is 6 degrees, and the azimuth of 81 to 16 degrees is recorded. Note that in the figure, x indicates the running direction of the magnetic ab 1, and y indicates the running direction of the head.

Figure 42 is a circuit diagram of a conventional VT'R. In the configuration, a conventional VTR has a recording system block 21, a head changeover switch 22. Rotary transformer 23° regeneration system block 24. It includes a tape running drive circuit 25 and a mode selection switch 26. The recording system block 21 includes a video transmission filter 211 and a "Rii degree 13" pass filter 2.
122 color signal passing filter, filter 213. F~1 demodulator 21
4. Addition circuit 215 (including 15 and σ low frequency modulator 216). Reproduction system block 24 includes head amplifiers 241 and 2
42. Addition circuit 243. FM video signal passing filter 24
4. FM demodulator 245° low-pass color signal passing filter 246
．． It includes a high frequency converter 247, an adder circuit 248, and an output terminal 249. The mode selection switch 26 includes the recording command switch 261. Regeneration command switch 262. Stop command switch 263. It includes a high-speed reproduction command switch 264 and a pause command switch 265.

Next, the operation of the conventional VTR will be explained with reference to FIGS. 1A, 1B, and 2.

First, signal processing in recording mode will be explained. In the recording mode, each switch 221 and 222 included in the head changeover switch 22 is switched to the upper side (the a contact side as shown).

The video signal generated from the video signal source 211 is approximately 3MH
It consists of a luminance signal up to 3.58MHz and a color signal of 3.58MHz. The luminance signal passes through a luminance signal pass filter 212 and is applied to an FM modulator 214 . The FM modulator 214 modulates the luminance signal from 3.4 MHz to a 4.4 MH2 FM signal and supplies it to the adder circuit 215. On the other hand, the color signal is
After passing through the color signal pass filter 213, the signal is passed through the low frequency converter 216.
given to. The low frequency converter 216 converts the color signal into 629k
It is converted into a Hz signal and provided to the adder circuit 215. The addition circuit 215 adds the FM-modulated luminance signal and the low-frequency converted color signal. This addition signal (V, that is, a frequency-modulated video signal) is given to the head 13 via a switch 221 included in the head changeover switch 22 and a transformer 231 included in the rotary transformer 23. The signal is applied to the head 12 via the signal line. The head 12 records one modulated video word (?is degree signal and color signal) on the A track. The head 13 receives a modulated video signal (
M degree signal and color signal) are recorded on 8 tracks.

Next, signal processing in playback mode will be explained.

In this case, the reproduction command switch 262 is pressed.

In response, the tape running drive circuit 25 switches each switch 221 and 222 included in the head changeover switch 22 to the lower side (b contact side) to switch to the reproduction system. In this state, the recording signal (i.e. video signal @) recorded on the A track 2 of the magnetic tape 1 is selected by the azimuth, reproduced by the head 12, and sent to the head amplifier 241 via the transformer 231 and switch 221. Given.

The head amplifier 241 amplifies the reproduced signal and sends it to the adder circuit 24.
Give to 3. Similarly, track B 3 of magnetic tape 1
The recording signal (that is, the video signal) recorded on the head 13 is reproduced.

It is applied to head amplifier 242 via transformer 232 and switch 222. The head amplifier 242 amplifies the reproduced signal and supplies it to the adder circuit 243. Addition circuit 243
adds the reproduced signals of both the A track 2 and the B track 3 and supplies the result to the FM video signal passing filter 244 and the low frequency color signal passing filter 246. The FM video signal passing filter 244 passes the FM video signal in the frequency band modulated by the FM modulator 214, and passes the FM video signal in the frequency band modulated by the FM modulator 214.
give to The FM demodulator 245 demodulates the FM video signal to derive a luminance signal and supplies it to the adder circuit 248. On the other hand, the low-pass color signal passing filter 246 is connected to the low-pass converter 21
The low frequency color signal of the frequency converted in step 6 is passed and applied to the high frequency converter 247. The high frequency converter 247 converts the low frequency color signal into a 3.58 MHz color signal and sends it to the adder circuit 2.
Give to 48. Adding circuit 248 adds the demodulated luminance signal and color signal and outputs the result to output terminal 249 as a video signal.

By the way, the conventional V as shown in FIGS. 1A and 2
When searching and confirming a large number of recorded images (screens), the TR presses the high-speed playback command switch 264 and rotates the capstan 16 at high speed while visually viewing the TV monitor and outputting the desired image. Sometimes, the operator presses the reproduction command switch 264, the stop command switch 263, or the pause command switch 265 to reproduce, stop, or pause the reproduction. There was a need. In other words,
With conventional VTRs, when searching for a desired screen during high-speed playback, it is necessary to search manually, which is cumbersome to operate, and there are also problems such as missing the desired image or running too much. there were.

Therefore, an object of the present invention is to provide a magnetic recording and reproducing device that can automatically and quickly search for a desired video during high-speed playback, and that can simplify operations for searching for a desired screen. That's true.

In summary, the present invention includes a first head and a second head having an azimuth different from that of the first head, and when a video signal is being recorded and at a timing when a video signal is to be searched, the video signal is detected. When different predetermined code signals are recorded and the code signals are played back in a high-speed playback state, the running speed of the magnetic tape is changed to a relatively slow speed (normal playback, pause or stop), and many video recordings are performed. This allows you to search for a desired video from within.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 3A is an illustrative diagram of a video recording section included in a VTR according to an embodiment of the present invention, and FIG. 138 is a diagram illustrating a recording state of the magnetic tape 1 recorded by the video recording section of this embodiment. It is.

The video recording section 10A of this embodiment differs from the video recording section 10 of FIG. 1A in that the head drum 11 is configured as follows. That is, in this embodiment, in addition to the first head 12, 13 used for recording or reproducing video signals,
M2 heads 18,19 are provided. This head 18
The head drum 11 is set so that the azimuth is different from that of the first head 12 for the A track (for example, +30 degrees).
It can be attached to ξ. Here, azimuth means the relative gap angle between the first head and the second head.

,, The second head 79 is attached to the head drum 11 at a different azimuth (for example, -30 degrees) than the first head 13 for the B track. , the mounting of the first heads 12, 13 is chosen to be approximately midway in angle. Azimuth different from head 12 of 1 (+
30 degrees) and has a predetermined frequency different from the frequency recorded by the first head 13. After that, the B (or A
) A video signal is overwritten on the T-rack by the first head 13 (or 12). Even if the second head 19 has an azimuth of t, l' -30 degrees, the second head 19
It performs the same function as the head 18 of.

FIG. 4 is a circuit diagram of a VTR according to an embodiment of the present invention.

This embodiment differs from the conventional one shown in FIG. 2 in that code generating means LI3 and control means are provided. The code generation means includes a code generation circuit 31 and a code recording command switch (first switch) 266. The control means includes head amplifiers 32, 33. Addition circuit 34. It includes a filter 35 and a control circuit 36.

Next, with reference to FIGS. 3A to 4, the VT of this example
The operation of R will be explained.

First, the recording operation will be described. When the recording command switch 261 is pressed, the tape running drive circuit 25 switches each of the switches 221 to 224 included in the head changeover switch 22 to the upper side (a contact side) in the same way as in the case of FIG. In this state J3, a one-frequency modulated video signal (including a luminance signal and a color signal) derived from the recording system block 21 is recorded on the n-air tape 1 by the first head 12.13. During the recording operation of video signals such as
When recording a video signal (or a screen), the code recording command switch 26G is pressed.

In response, the tape running drive circuit 25 derives a code recording command signal a and supplies it to the code generation circuit 31.

The code generation circuit 31 generates a code signal with a frequency of, for example, 1.0M to IZ. This code signal is supplied to the second head 18 via the switch 223+13 and the transformer 233, and is also supplied to the second head 19 via the switch 224 and the transformer 234. As a result, the code signal is overwritten by the heads 18 and 19 on tracks A and B on which the video signal is recorded (mark recording).

Note that the recording of the code signal is not limited to recording a code consisting of marks and spaces at a constant frequency, but may also be recorded as marks using the frequency step method as follows. for example,
Code 1 to 1. OMH2, code 2 is 1.2MH2, code 3 is 1.4MH2.

Code 4: 1.6MH2, :I-do 5: 1.8M1-1
If it is set to 2, any 5'f# type code can be recorded. However, since the track on which the video signal is recorded is overwritten with a different azimuth, it is necessary to select a frequency that is different from the frequency of the video signal whose frequency has been changed in order to prevent negative effects such as noise on the reproduced image. .

Next, the playback operation will be described. When a magnetic tape on which a video signal and a code signal for search are recorded is to be played back at high speed to search for an image on which the code signal is recorded, the high speed playback command switch 265 is pressed. In response to this, the tape running drive circuit 25 rotates the take-up reel 15 and capstan 16 at high speed. At the same time, search command switch 267 is pressed. In response, the tape running drive circuit 25 switches each of the switches 221 to 224 of the head changeover switch 22 to the lower side (b contact side). Further, the tape running drive circuit 25 derives a search command signal @b and activates the control circuit 36. During the period when the magnetic tape is running at high speed and being reproduced at high speed, the second head 18 reproduces the 1.0 MHz code signal recorded on the Δ track, and the second head 19 reproduces the 1.0 MHz code signal recorded on the B track. The generated 1,0MH2 code signal is reproduced. The code signal reproduced by head 18 is given to head amplifier 32 via transformer 233 and switch 223. The code signal reproduced by the second head 19 is transmitted to the head amplifier 3 via a transformer 234 and a switch 224.
given to 3.

These code signals are amplified by head amplifiers 32 and 33, added by an adder circuit 34, and sent to a filter 3.
given to 5. The filter 35 is attached to the second head 18 .
The frequency of the code signal (1,
Since it has a passband width of ○Fill HZ), only the code signal is extracted and given to the control circuit 36. control ti1
1 circuit 36 generates a signal C for instructing a change in the running state in response to the application of a predetermined load signal in the enabled state and activates the tape running drive circuit. Give to 25. Tape running drive circuit 25
In response to the input of the signal C, the drive state of the take-up reel 15 and the capstan 1G is controlled so as to change the running state from high-speed playback to one-inch stop.

Accordingly, in this embodiment, a code signal is recorded in recording mode so as to correspond to a desired image to be searched during high-speed playback, and when it is detected in high-speed playback mode, the code signal is paused. Because
This has the advantage of being able to search for a desired screen on its own during high-speed playback. In addition, the frequency of the search code signal is different from the modulation frequency of the video image signal, and the azimuth is selected to be different from the recording of the video signal, so it will not have any adverse effects during playback. It also has the advantage of preventing

In addition, if several types of code signals are selected, only when the control circuit 36 detects the code specified by the operator by operating the search command switch 267, the signal C for instructing to change the running state is generated. The configuration of the control circuit 36 may be selected so as to do so. By doing so, there is an advantage that a desired screen can be selected and searched from among a plurality of screens recorded on one magnetic tape.

In the above-described embodiment, as an example of changing the running state of the magnetic tape, a case is described in which the magnetic tape is temporarily stopped when a code signal is detected in the high-speed playback mode.
The running state is not limited to this, and the running state can also be changed to stop or normal regeneration. In addition, in the normal playback mode, by performing the same operation, the playback can be paused or stopped at the timing when a code signal is detected during playback.

It is also possible to automatically search by stopping or playing at high speed, or by changing the running state.

Further, as the code recording, in addition to the above-mentioned mark recording, recording of a time signal or recording of a frame number may be performed. Furthermore, as a method for recording the code signal, instead of using a code signal based on a stepwise change in frequency, a code based on FSK, PPM, or a modulated wave can also be used.

As described above, according to the present invention, it is possible to automatically search for a desired image among the images recorded on a magnetic tape and change the running state of the magnetic tape, and also to prevent interference from being caused to reproduction signals. This brings about unique effects such as being able to reduce noise interference and eliminating noise interference on the screen. Furthermore, since the recording by the second head precedes the recording by the first head, interference with the reproduced signal can be further reduced.

[Brief explanation of drawings]

FIG. 1A is an illustrative diagram of a conventional video recording section, and FIG. 1B is an illustrative diagram of a recording state of a magnetic tape recorded by the conventional video recording section. FIG. 2 is a circuit diagram of a conventional VTR. FIG. 3A is an illustrative view of a video recording section according to an embodiment of the present invention, and FIG. 3B is a diagram illustrating a recording state of a magnetic tape recorded by this video recording section. FIG. 4 is a circuit diagram of a VTR according to the -* embodiment of the present invention. In the figure J3, 1 is a magnetic tape, 10.10A is a video recording unit, 11 is a head drum, 12.13 is a first head, 14 is a supply reel, 15 is a take-up reel, 16 is a capstan, and 17 is a Pinch roller, 18. 19 is the second head, 21 is the recording system block, 22 is the head changeover switch, 23 is the rotary transformer, 24 is the reproduction system block, 2
5 is a tape running drive circuit; 26 is a mode selection switch;
31 is a code generation circuit, 32.33 is a head amplifier, 3
4 is an adder circuit, 35 is a filter, and 36 is a control circuit.

Claims (4)

[Claims] (1) A running drive means for controlling the running state of the magnetic tape based on the selected operation mode, a head drum rotatably provided at the running position of the magnetic tape, and a frequency modulated drive unit mounted on the head drum. a first head for recording video signals on the magnetic tape or reproducing video signals recorded on the magnetic tape; generating a predetermined code for searching the magnetic tape at a predetermined timing in a recording mode; a code generating means, mounted on the head drum so as to have an azimuth different from that of the first head, and recording a predetermined code generated by the code generating means on the magnetic tape, or a predetermined code recorded on the magnetic tape; a second head for reproducing a code; and a running drive means configured to change the running state of the magnetic tape in response to generation of the predetermined code by the second head in the playback mode. The magnetic recording/reproducing side L is equipped with a control means for controlling the magnetic recording/reproducing side L. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the code generating means includes a first switch for instructing generation of the predetermined code by operating the code generating means. (3) The magnetic recording/reproducing apparatus according to claim 11!4, wherein the control means includes a second switch for activating the search for the predetermined code in the reproduction mode. (4) The travel driving means causes the magnetic tape to travel at high speed when the high speed playback mode is selected, and relatively moves the magnetic tape in response to the reproduction of the predetermined code during the high speed playback mode. The magnetic recording/reproducing device according to claim 1, which changes the speed to a low speed.