JPH0568792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape search method that automatically writes an address search signal when recording a video signal or the like on a long magnetic tape.

[Conventional technology]

Recent magnetic tape devices have advanced in high-density recording1.
It is now possible to record and play back 6 to 8 hours with a single cassette, and as tape lengths continue to increase, the need for a tape cue (search) function becomes more necessary than before, but we are currently satisfied with this. I don't see anything that can be done.

In many conventional consumer magnetic tape devices, the number of rotations of the tape supply reel disk, tape take-up reel disk, etc. is counted to find the beginning. This has a large error and requires counting from the start point of the tape in the cassette tape, making it impossible to cue from the middle of the tape.

Although there is no prior art example applicable to this invention,
The configuration of a counter using a control signal counting method, which has recently been adopted in VTRs (video tape recorders) as a counter with high retrieval accuracy, will be explained below.

Figure 3 shows the tape running in the recording/playback mode (loading state) of the parallel loading method. This is a video head that slightly protrudes and is fixed to the top of the video head and rotates at high speed together with the rotating drum 1.

The video heads 1a, 1b are each indexed at exactly 180° relative to the center of the rotating drum 1.

2a and 2b are loading tape guides on the supply side, and 2a1 and 2b1 are loading tape guides on the take-up side, both of which are connected to the rotating drum 1.
It has the function of stably mounting the magnetic tape 3 on the 4 loading guides 2a, 2b, 2.
a1 and 2b1 move while pulling out the magnetic tape 3 during the loading operation, as shown by arrows.

The guide roller 4a on the supply side and the guide roller 4b on the take-up side are impedance rollers that reduce small vibrations of the magnetic tape 3 and reduce jitter.

The full width erasing head 5 erases the entire width of the magnetic tape 3 when a recording mode for recording video signals and audio signals is designated.

Tape guides 6 and 7 and a tape tension regulator 8 are arranged near the full-width erasing head 5.

Further, an audio erasing head 9 and an audio signal/control signal head 10 are arranged near the guide roller 4b.

Generally, the audio cancellation head 9 and the audio signal/control signal head 10 are integrated to provide mechanical precision.

A tape guide 11 and a pinch roller 12 are provided near the audio signal/control signal head 10, and a magnetic tape 3 is attached to the pinch roller 12.
The capstan 13 is brought into pressure contact with the capstan 13 via the capstan 13.

As the capstan 13 rotates, the magnetic tape 3 is sent out at a constant speed in the direction of the arrow.

On the other hand, 14 is a cassette, and this cassette 14
A magnetic tape 3 is housed inside. Tape guides 15 to 17 are provided within the cassette 14, and these tape guides 15 to 17 smoothly supply and wind up the magnetic tape 3 stored in the cassette 14. ,
A supply reel 18 and a take-up reel 19 are housed in the cassette 14.

In the magnetic tape device configured in this way, the magnetic tape 3 runs as shown in FIG.
In the playback operation mode, the video heads 1a, 1
b. The audio erasing head 9 and the audio signal/control signal head 10 come into contact with the magnetic surface of the magnetic tape 3 and perform their respective operations.

When in the recording mode in this loading state, the loading guide 2
a, 2b, 2a1, 2b1, and the tape guide 7 move to the position indicated by the broken line, and output audio signals to the audio signal track A, video signal track B, and control signal track C of the magnetic tape 3, respectively.
Record video and control signals.
Here, the control signal is recorded based on the vertical synchronization signal of the composite video signal. At the same time, this pulse signal is counted and displayed on a counter.

During playback, the video signal and audio signal are played back in the loading state shown in FIG. 3, and the control playback signal is used as a signal to control the servo system, and is simultaneously counted and displayed on a counter.

Next, the rewind and fast forward modes will be explained based on FIG. In FIG. 5, during rewinding and fast forwarding operations, the movable tape guide 20 on the winding side moves to the stop position shown by the solid line, and the magnetic tape is transferred to the audio signal/control signal head 10, as shown in FIG. Touch it and pick up the control signal.

Generally, the tape speed during rewind and fast forward operations is approximately 40 times faster than in recording and playback modes.
As shown in FIG.
The control signal is picked up, added to the counting circuit, and displayed on the counter.

This method counts vertical synchronization signals or control signals, so the display accuracy is good.

[Problem that the invention seeks to solve]

Conventional VTR equipment is configured as described above, so it is possible to configure a counter (counter method that calls control signals) with high search accuracy.
This counter display allows you to know the counter value only by counting from the head of the cassette. If you load a cassette tape with the tape inside the cassette in the center into a VCR, the tape will be rewound to the head of the cassette. (for several minutes) and then sequentially counting the control signals, which is a tedious task.

Furthermore, when recording from the middle of a tape, it is necessary to find out how many times from the beginning of the tape the recording begins, and this method is not actually used.

This invention was made to solve this problem, and even if recording starts from the middle of the tape, the previously recorded address signal is retrieved by a slight rewind operation (knowing the N address), and then the TeN+
To provide a tape retrieval system that can automatically record addresses continuously at all times by including address 1 and writing N+1 again when recording ends and enters a stop mode.

[Means for solving problems]

The tape search method according to the present invention writes a search address number of address N to the magnetic tape when recording a video signal on the magnetic tape, and uses the search address number of address N that was recorded immediately before entering the unloading state in stop mode. The apparatus is provided with means for writing an address number in a predetermined position, detecting the address number at address N at the start of a new recording operation, and writing the address number at address (N+1).

[Effect]

In this invention, a search address number of the N address is written on a part of the magnetic tape at the same time as the video signal is recorded, the N address is memorized during the recording mode, and the N address is searched again when the recording mode ends. At the same time, the address number for searching at address N is detected, and then the address number for searching at address (N+1) is detected by mounting the magnetic tape so that it is located in the middle of the magnetic tape and entering the recording mode. and write the period of this new recording mode (N+
1) Record the search address number for the address, and then record the search address number for address (N+1) again when the recording mode ends. Even if you record from any position on the magnetic tape, the address signal will not come from the head of the magnetic tape. Record "1", "2"..."N", "N+1" in sequence.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the tape search method of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment, and in this FIG.
The same parts as in FIGS. 3 and 5 are given the same reference numerals to avoid redundant explanation, and parts different from FIG. 3 will be mainly described.

In this FIG. 1, 1, 1a, 1b, 2a,
For 2a1, 3, 10, 12, 13, the third
It is the same as that shown in FIG.

Further, 30 is a changeover switch for operating the audio signal/control signal head 10 in the recording/playback mode, the movable contact of which is connected to the audio signal/control signal head 10, and the fixed contact 30a of the address recording amplifier 36. The fixed contact 30b is connected to the output end and is connected to the address reproducing amplifier 31.
is connected to the input end of the

This address reproduction amplifier 31 picks up and amplifies the signal written on the control signal track on the magnetic tape 3.

The output of this address reproduction amplifier 31 is output to a control code signal discrimination circuit 32 that discriminates the signal written in the control signal track, and the output of this control code signal discrimination circuit 32 is output to an address signal decoder 33 that decodes the address signal. It is becoming more and more common.

The address signal decoder 33 includes an address address call control circuit 34 for calling an address.
The output of the address signal decoder 33 is also output to an address number memory circuit 35 that stores address numbers.

On the other hand, 42 is a key button circuit, and by operating this key button circuit 42, a search address number is input to the sequence control circuit 41. This sequence control circuit 41 is in charge of sequence control of the entire VTR, and outputs from the address write control circuit 39 and the call control circuit 3.
It is set to output to 4.

The address write control circuit 39 is for writing the search address number, and its output is output to the address signal encoder 38.

Further, the output of the address number memory circuit 35 is outputted to an address number (N+1) circuit 40. This address number (N+1) circuit 40 adds "+1" to the numerical value of the address number memory circuit 35, and its output is sent to the address signal encoder 38.

The output of the address signal encoder 38 is output to the control code signal generation circuit 37. Control code signal generation circuit 37
creates a control code signal including an address number signal and outputs it to the address recording amplifier 36.

Next, the operation will be explained. First, the case where the N address is designated and the recording mode is started will be described. The N address is designated by the key button circuit 42,
The sequence control circuit 41 operates and the recording mode by the video head is started at the same time as the loading state shown in FIG. 3 is entered.

At this time, the write control circuit 39 operates and N
At the same time as storing the address number, the address signal encoder 38 encodes the number N, and the control code signal generation circuit 37 generates an address signal to be written to the control signal track.

Here, the control signal is a 1/30HZ pulse signal, so you can insert an address signal between these pulse signals, or change the duty of the 1/30HZ control signal to make it a bit signal, and use multiple of these control signals. There is a way to encode it.

Currently, the latter is chosen for consumer VTRs in terms of reliability and cost. The control code signal containing the address signal is sent from the control code signal generation circuit 37 to the address recording amplifier 36, where the current is amplified, passed through the changeover switch 30, and then sent to the audio signal/control signal head 10. The signal is written to the control signal track on the magnetic tape 3 as shown in FIG. 2A.

As shown in Figure 2A, write the search address number N at the start point of the recording mode (this
( _N3 ) After that, normal recording is performed by the video head and audio head until the predetermined time _T1 ends.

At the same time as the recording for the predetermined time _T1 is completed and the stop mode is instructed by the sequence control circuit 41,
Address N is written again while the loading state remains (set as N _E ). That is, as shown in FIG. 2A, the range from address N _S to address N _E is recorded by the address of address N.

Next, when the cassette located in the middle of the magnetic tape 3 is loaded into the VTR, the rewind mode is activated by the sequence control circuit 41 in the half-loading state shown in FIG.
, and is rewound to the position of address N _E.
That is, the control signal is called out faster than the audio signal/control signal head 10 in the half-loaded state.

At the same time that the sequence control circuit 41 specifies the half-loading state and the rewind mode, the call control circuit 34 and the changeover switch 30 are driven, and the address signal picked up from the control signal track is transferred to the changeover switch 30 and the address signal reproduction amplifier 31. via a control code signal discrimination circuit 32 and an address signal decoder 33.
is applied to detect the position of N _E.

Here, at the same time as storing the N address in the address number memory circuit 35, the loading state is transferred from the half-loading state shown in FIG. 5 to the loading state shown in _FIG . Write the address of (Figure 2B).

This is address number (N+1) circuit 4 in Figure 1.
0, “+” is written to the N address of the address number memory 35.
1" address is recorded. This is (N+1) _S
shall be. Then, as described above, address (N+1) _E is written at the same time as the recording time _T2 ends.

In this way, address numbers can be automatically and consecutively recorded one after another as shown in FIG. 2C by recording arbitrarily from the middle of one cassette and repeating the above-mentioned operation whenever necessary.

When simply searching for an address and reproducing the data, it is sufficient to specify the address using the key button circuit 42 in FIG. 1 and specify reproduction using the sequence control circuit 41. At this time, a high-speed search is first performed in the half-loading mode shown in FIG. 5, and after a predetermined address is searched, the state shifts to the loading state shown in FIG. 3, and a reproduction operation is performed.

Also, as explained above, when writing the same address, it is good to distinguish between the start point N _S and the end point N _E , or to differentiate the start point by fast forward direction and rewind direction at the same N address. Points and end points can be distinguished.

Furthermore, as can be seen from FIG. 2C, it is also possible to write only the end point N and omit the start point N address. That is, (N+1)
When writing an address, all of the above explanations and operations can be performed by finding the end point at address N, then continuing recording on the video head and audio head, and writing the address at address (N+1) at the end.

〔Effect of the invention〕

As explained above, in this invention, the address number is recorded at the beginning and end of the recording mode, and "+I" is written in the number in the next recording mode, so that one volume of cassette tape can be Even when recording from a certain location, the addresses are written in order from the beginning of the tape each time the tape is recorded, and the addresses are written automatically, which has the effect of providing the most desirable tape address search method for consumer VTRs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the tape search method of the present invention, and FIG. 2 is a diagram showing a tape address writing state for explaining the operation of the same tape search method.
FIG. 3 is a plan view showing the loading state of the magnetic tape of a conventional VTR, and FIG. 4 is a diagram showing the recording tape format on the magnetic tape of a conventional VTR.
FIG. 5 is a plan view showing a half-loading state of the magnetic tape of a conventional VTR. 1... Rotating drum, 1a, 1b... Video head, 3... Magnetic tape, 10... Audio signal/control signal head, 30... Selector switch, 3
2... Control code signal discrimination circuit, 33...
...Address signal decoder, 34...Address address call control circuit, 35...Address number memory circuit, 37...Control code signal generation circuit, 38...Andres signal encoder, 39...
. . . address write control circuit, 40 . . . address number (N+1) circuit, 41 . . . sequence control circuit, 42 . . . key button circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 When the video signal starts to be recorded on the magnetic tape, the search address number of address N is recorded on a part of this magnetic tape, and when the stop mode is specified, the above-mentioned recording is performed immediately before the magnetic tape enters the unloading state. address recording means for rewriting the search address number of address N in a predetermined position;
An address number memory circuit that stores the search address number for at least the recording period; when the magnetic tape starts a new recording operation, it automatically rewinds slightly and detects the search address number of the N address; 1. A tape retrieval method, comprising means for writing (N+1) addresses into the address recording means.