JPH0714368A - Video tape recorder - Google Patents

Abstract

PURPOSE:To improve accuracy of retrieving by detecting a program searching signal within a set range decided by tape position information in which the beginning of a program recorded in a magnetic tape is read out from a memory means. CONSTITUTION:When a program searching signal within a setting range decided by tape position information of recording start from a SRAM 11 storing information of a television program recorded in a magnetic tape 2 at the time of reproducing, position information of the tape 2 and the like is retrieved or detected, after it is compared, and collated whether a position of the tape 2 at the time of detection is within the set range or not, and reproducing is started.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video tape recorder (hereinafter referred to as "VTR") having a reproducing function, which is effective when searching information recorded on a magnetic tape, and the search accuracy is dramatically improved. To improve.

2. Description of the Related Art As a means for retrieving a program designated by a user from program information at the time of reproduction in a conventional VTR, tape position information at the beginning of the program is read out from a memory means, and the read tape position at the beginning of the program is present. If the tape is located at the end of the tape rather than the tape position, it is compared with the current tape position information obtained from the tape position information, and by calculation, the end side of the recording position of the cueing signal recorded on the tape which is the beginning of the program. After fast-forwarding to the position where the tape has passed, the tape is rewound until the cue signal is detected.If the read tape position at the beginning of the program is at the beginning of the tape rather than the current tape position, the tape position is the same as above. The head recorded on the tape which is the beginning of the program by comparing and calculating with the current tape position information obtained by the information After rewinding the recording position of the to signal to a position which has passed through the starting end, but to automatically search for the beginning of the program by performing the fast-forward to the detection of the cue signal.

As a problem in the above method for searching the beginning of a recorded program, the tape position information at the beginning of the program read from the memory means and the current tape position information are compared and calculated. The program is moved to a position where it has passed from the recording position of the cueing signal recorded on the tape at the beginning of the program to the start end side or the end side,
To search for a cue signal, when a plurality of cue signals exist near the tape position of the cue signal to be searched, an unintended cue signal may be detected, resulting in a program search error.

In order to solve the above problems, the present invention provides a tape position detecting means for detecting the amount of advance of the magnetic tape or the remaining tape position, and a cue signal recorded on the tape. A cue signal detecting means for detecting
It is provided with a tape transfer means for fast-forwarding or rewinding the tape and a calculating means for comparing and calculating the tape position information at the beginning of the program stored in the memory means and the tape position information detected by the tape position detecting means. When searching, only the cue signal within the preset range determined by the tape position information at the beginning of the program is searched, or if the cue signal is detected, the tape position at the time of detection is compared and confirmed. By doing so, the beginning of the program designated by the user is searched and reproduced.

According to the present invention, with the above-described structure, the cueing signal is detected within the setting range defined by the tape position information at the beginning of the program read from the memory at the beginning of the program specified by the user and recorded on the magnetic tape. By doing so, the search accuracy is improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a video tape recorder of the present invention, which is a cassette 1 for storing a magnetic tape 2 and a rotary drum for driving a rotary head (not shown) for recording / reproducing information on / from the magnetic tape 2. 3 and
A supply-side reel (hereinafter abbreviated as S reel) 4 that feeds out the magnetic tape 2 at the time of reproduction or fast-forward, and a take-up reel (hereinafter abbreviated as T-reel) at which the magnetic tape 2 is wound at the time of reproduction or fast-forward. 5 and a control head 8 for recording / reproducing a control signal for servo.
And a control signal recording / reproducing circuit 10 for writing / reading a cue signal to / from the magnetic tape via the control head 8, and for transferring the magnetic tape 2 in accordance with the FF / REW state or the reproducing state of the VTR. , A tape drive circuit 12 for driving a capstan motor (not shown) or a reel motor (not shown), and V
A key input device for TR operation or a remote control device 13, a static random access memory (hereinafter, abbreviated as SRAM) that stores program information regarding recording and tape remaining amount information and is backed up by a battery (not shown) at the time of power failure. ) 11, an on-screen display (hereinafter abbreviated as OSD circuit) 14 for displaying program information stored in the SRAM 11 when necessary, a video signal processing circuit 15, a monitor 16, and a micro controller for controlling the above system. The whole is constituted by the computer 9. With the above configuration, the microcomputer 9 in this VTR reads program information from the SRAM 11,
The process of searching the information recorded on the magnetic tape, that is, the recorded video and audio, and reproducing the information will be described below. Here, the program information stored in the SRAM 11 is, for example, a channel, a recording date, and
Information about the start and end times of recording is considered, and the user can recognize the recorded contents by the monitor 16 when searching a program and the tape position information of the program. The tape position information is for storing where on the tape the information to be recorded is recorded, and by measuring the rotation cycle of the S reel 4 and the rotation cycle of the T reel 5, for example, recording start It is the remaining tape time from the position to the end of the tape. FIG. 2 is an enlarged view of a portion of the cassette 1 of FIG. 1, and an embodiment of the method for detecting the remaining tape time of the microcomputer 9 will be described in detail with reference to FIG. In FIG. 2, Vt is the traveling speed [m / s] of the magnetic tape 2,
r is the hub diameter [m] of S reel and T reel, Rs and Rt
Is the radius [m] to the outer circumference of the magnetic tape wound on the S reel and the T reel, and Ss and St are S
The area including the magnetic tape wound around the reel and the T reel and the reel hub [m ² ], ωs and ωt are respectively S
It is the rotational angular velocity [rad / s] of the reel and the T reel. The angular velocities ωs and ωt can be obtained by measuring the cycle of the rotation speed detection signals detected by the S reel rotation speed detector 6 and the T reel rotation speed detector 7. Therefore, the radii Rs and Rt to the outer circumference of the magnetic tape wound around the S reel 4 and the T reel 5 are obtained by the following equations.

[Equation 1]

[Equation 2] Therefore, the total area S of the tape including the reel hub, which corresponds to the length of the magnetic tape wound around this cassette, is given by the following equation.

[Equation 3] By the way, there are several kinds of lengths of the magnetic tape wound on the cassette 1. For example, in the above-mentioned VHS standard,
There are 20 minutes tape, 90 minutes tape, 60 minutes tape, 30 minutes tape and so on. Therefore, if the total tape areas S ₁₂₀ , S ₉₀ , S ₆₀ , and S ₃₀ are obtained in advance for each tape, it is possible to detect how many minutes the cassette 1 currently inserted in the VTR is. Based on the result, the area Sso including the reel hub on the S reel side is obtained again. If, for example, the detection result is 120 minutes tape, Sso
Is expressed by the following equation.

[Equation 4] Then, by dividing the net tape area excluding the reel hub area by the tape thickness τ [m], the remaining tape amount L [m] is calculated by dividing this by the tape speed, and the remaining time T
[S] can be calculated. That is,

[Equation 5]

[Equation 6] The tape remaining amount information is obtained by calculating A method of recording a VISS signal in this VTR and a cueing method using the VISS signal (hereinafter, abbreviated as VISS search) will be described. Microcomputer 9
Is a cue signal obtained by duty-modulating the control signal by the control signal recording / reproducing circuit 10 of FIG. 1 at the start of recording, that is, VISS of VTR of so-called VHS system.
The signal is recorded on the magnetic tape 2. FIG. 3 shows a recording waveform of a control signal, a reproduction waveform, and a recording format of the cueing signal for explaining the VISS search function for performing the cueing by duty-modulating the control signal. A signal having a high level (hereinafter abbreviated as H level) period of about 60% (FIG. 3 (A)) is a "0" pulse when 100% is set, and a signal having an H level period of about 27.5%. (Fig. 3 (B))
Is set to a "1" pulse, and a cue code as shown in FIG. 3C is recorded at the start of recording, that is, at the beginning of the program to be recorded. Then, at the time of VISS search, the cue code is detected by measuring the duty of the reproduction control signal at the time of fast forward or rewind,
This is to shift to the reproduction mode. A method for searching the beginning of a program using each of the above methods will be described in detail with reference to the tape running diagram shown in FIG. In FIG. 4, 17 is a simulated view from the beginning to the end of the tape, 18 is a locus indicating the running direction of the tape, A is the current tape position, B is the recording start position of the program, and the hatched portion of B is control. It is a VISS signal written by the signal recording / reproducing circuit 10. First, in (a) and (b), the microcomputer 9 detects the position A, that is, the current tape winding position, by the tape remaining time detecting method described above.
Next, the tape remaining time detected at the position B, that is, at the time of recording of the selected program and stored in the SRAM is compared with the tape remaining time at the position A, and the result is selected. Determine the search direction of. That is, it is determined whether the current position is on the start side or the end side with respect to the target position. The operation in each case will be described below. First, (a) is a search method when the current position is on the start side with respect to the beginning of the program. Microcomputer 9 is A
When it is judged that the position of is on the starting end side with respect to the position of B, a command is sent to the tape drive circuit 12 to fast forward the VTR (FF).
State. During this time, the microcomputer 9 detects the position of B, that is, at the time of recording the selected program, and detects the SRAM 11
The size of the remaining tape time stored in is compared with the current remaining tape time. When the tape position reaches the position C which exceeds B, a command is sent to the tape drive circuit 12 and V
Put TR in a stopped state. Next, the microcomputer 9 keeps the VTR in the REW state and always keeps the current tape position and SR.
Correctly return to the set position D while collating with the tape position read from the AM 11. Then REW from position D
While continuing the state, the VISS search is performed to the position E, and the control signal recording / reproducing circuit 10 makes the V position V
When the ISS signal is detected or when the position E is reached, the VTR is set to the reproduction mode and the series of search operations is completed. In other words, the recorded position of the program is roughly detected by the tape remaining amount detecting function, then accurately moved to the vicinity based on the tape position information, and then highly accurately detected by the VISS search function. Here, as a reason for providing the set positions D and E, conventionally, when the tape position reaches the position C which exceeds B, the microcomputer 9 stops the VTR and makes the REW state from that position to perform the VISS search. This conventional method has no problem when the beginnings of a plurality of programs recorded on the tape are separated,
When a short-time program is recorded continuously, a search error may occur, and as a result, measures such as when the VISS signal interval is very short have not been perfect. The first cause of such a search error is that in a general VTR, FF or REW does not transfer the tape at a constant speed with a capstan but drives the S reel and T reel to send the tape. , The tape traveling speed Vt does not become constant depending on the winding position of the tape, and the actual V
The travel distance of the tape changes until TR becomes a stop state, it passes after considerably passing the position of C and then stops, and the VISS search should have been started from the position of C to the position of F. And as a result, VIS between FCs
I have detected the S signal. Secondly, when the VISS search mode is entered, the tape position information at the beginning of the program read from the SRAM is not compared or collated. Therefore, even if the VISS signal is detected, it can be determined whether or not it is the VISS signal to be searched. There wasn't. Therefore, in order to start the VISS search from a position as accurate as possible and to search within an effective range, the tape position information at the beginning of the program designated by the user is set as the origin, for example, ± 1 minute is set as the setting range, and only this setting range is set. VISS search allows multiple Vs in the vicinity
Even if the ISS signal is present, the search target VISS signal can be specified. Next, FIG. 3B shows a search method when the current position is on the end side with respect to the beginning of the program. When the microcomputer 9 determines that the position A is on the end side with respect to the position B, it issues a command to the tape drive circuit 12 to put the VTR in the rewind (REW) state. During this period, the microcomputer 9 compares the tape remaining time detected at the position B, that is, at the time of recording the selected program and stored in the SRAM 11, with the current tape remaining time.
When the tape winding position reaches the position C which exceeds B, a command is sent to the tape drive circuit 12 and the VTR is stopped. Next, the microcomputer 9 sets the VTR to the FF state and always returns to the set position D while collating the current tape position with the tape position read from the SRAM. After that, while continuing the FF state from the position of D, E
When the control signal recording / reproducing circuit 10 detects the VISS signal at the position B or when it reaches the position E, the VTR is set to the reproducing mode and a series of search operations are completed. Next, another search method using the tape position information will be described. First, there is a search method when the current position is on the start side with respect to the beginning of the program. The position of A in the microcomputer 9 is B
When it is determined that the position is on the starting end side with respect to the position of (1), a command is sent to the tape drive circuit 12 to set the VTR to the fast forward (FF) state. During this period, the microcomputer 9 compares the tape remaining time detected at the position B, that is, at the time of recording the selected program and stored in the SRAM 11, with the current tape remaining time. When the tape winding position reaches the position C which exceeds B, a command is sent to the tape drive circuit 12 and V
Put TR in a stopped state. Next, the microcomputer 9 sets the VTR to the REW state and performs the VISS search. When the control signal recording / reproducing circuit 10 detects the VISS signal, it determines whether the tape position is within the set range. When the tape position information at the beginning of the program read out from the SRAM 11 is set as the origin, for example, ± 1 minute, the setting range is the beginning of the program that the user wants to search if the tape position at which the VISS signal is detected is within this range. Judge and V
The TR is switched to the reproduction mode, and the series of search operations is completed. If it is out of the set range, it is judged that the program is not the beginning of the program by the user, and the VISS search is continued. That is, when the recorded position of the program is roughly detected by the tape remaining amount detecting function and then the VISS signal is detected by the VISS search function, it is collated with the setting range defined by the tape position information read from the SRAM 11 to determine the user's position. It is to judge whether it is the beginning of the designated program. In the above-mentioned method, the setting range is set to limit the portion for performing the VISS search to improve the search accuracy. However, in this method, the tape position is confirmed every time the VISS signal is detected, contrary to the above-mentioned method. To prevent search mistakes,
If the setting range is the same as the above method, the accuracy is the same. Next is a search method when the current position is on the end side with respect to the beginning of the program. When the microcomputer 9 determines that the position A is on the end side with respect to the position B, it sends a command to the tape drive circuit 12 to rewind the VTR (RE
W) state. During this period, the microcomputer 9 detects the position of B, that is, at the time of recording the selected program, and detects the SRAM.
The size of the remaining tape time stored in 11 is compared with the current remaining tape time. When the tape winding position reaches the position C which exceeds B, a command is sent to the tape drive circuit 12 and the VTR is stopped. Next, the microcomputer 9 sets the VTR to the FF state and performs the VISS search. When the control signal recording / reproducing device 10 detects the VISS signal, it determines whether the tape position is within the set range. The setting range is, for example, ± 1 with the tape position information at the beginning of the program read from the SRAM 11 as the origin.
In the case of minutes, if the tape position where the VISS signal is detected is within this range, it is judged that the user is the beginning of the program to be searched, the VTR is shifted to the reproduction mode, and the series of search operations is completed. If it is out of the set range, it is judged that the program is not the beginning of the program by the user, and the VISS search is continued.

According to the video tape recorder of the present invention, the tape is transported based on the tape position information at the beginning of the program stored in the memory, and the video tape recorder is improved so that the program specified by the user can be searched accurately. It eliminates search mistakes and improves search accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a video tape recorder of the present invention.

FIG. 2 is an enlarged view of a cassette portion of the same embodiment.

FIG. 3 is a recording format diagram of a control signal recording waveform and a cueing signal for explaining the VISS search function of the embodiment.

FIG. 4 is a diagram showing an example of a tape running operation at the time of program search of the embodiment.

[Explanation of symbols]

 1 cassette 2 magnetic tape 3 rotating drum 4 supply side reel 5 winding side reel 6 supply side reel rotation speed detector 7 winding side reel rotation speed detector 8 control head 9 microcomputer 10 control signal recording / reproducing circuit 11 SRAM 12 tape Drive circuit 13 Key input device 14 On-screen display circuit 15 Video signal processing circuit 16 Monitor

Claims (2)

[Claims] 1. A memory means for storing program information such as recording start / end time and recording channel of a TV program recorded on a magnetic tape, tape position information, etc., a reading means for reading information from the memory, and the magnetic tape. Tape position detecting means for detecting the advanced amount or the remaining tape position, a cue signal detecting means for detecting a cue signal recorded on the tape, and a tape transfer means for fast-forwarding or rewinding the tape, The tape position information stored in the memory means and the current tape position information detected by the tape position detection means are provided for calculation, and a program specified by the user is searched by the program information during reproduction. In this case, the tape position information at the beginning of the program is read from the memory means by the reading means to detect the tape position. If it is in the tape end direction from the current tape position by comparing and calculating with the current tape position information obtained by the means, it ends from the recording position of the cueing signal recorded on the tape which is the beginning of the program. Fast forward to the position where it passed to the side, and then rewind in the reverse direction again, during that time, while constantly comparing the tape position information during transfer with the tape position information at the beginning of the program read from the memory, the beginning of the program The program is automatically moved to the beginning of the program by transporting it to a preset position just before the tape position where the cueing signal is recorded and then rewinding until the cueing signal detecting means detects the cueing signal. When the tape position information at the beginning of the program read from the memory means is located in the tape start end direction rather than the current tape position, The tape is rewound from the recording position of the cueing signal recorded on the tape at the beginning of the program to the position where it passed to the beginning side, and then fast-forwarding is performed in the reverse direction again, while tape position information and memory during transfer are recorded. While constantly comparing the tape position information at the beginning of the program read from the above, the tape is moved to a preset position immediately before the tape position where the cueing signal at the beginning of the program is recorded, and then the cueing signal detecting means is used. A video tape recorder characterized by being configured to automatically search for the beginning of a program and start playback by re-fast-forwarding until a cue signal is detected. 2. When retrieving the beginning of a program designated by the user from the program information during reproduction, the tape position information of the recording start of the program is read from the memory means by the reading means, and the tape position detecting means is used. When the beginning of the program is in the tape end direction rather than the current tape position by comparing and calculating with the obtained current tape position information, the cue signal recorded on the tape, which is the start position of the program, is recorded. After fast-forwarding from the recording position to the position passed to the end side, rewinding is performed until the recorded cueing signal detected by the cueing signal detection is detected, and the beginning of the program is in the tape start direction from the current tape position. If it is, rewind to the position where it passed from the recording position of the cue signal recorded on the tape which is the start position of the program to the start side. After that, fast-forwarding is performed until the cueing signal recorded by the cueing signal detection is detected, and when the cueing signal is detected, the tape position at the time of detection is the recording start tape read from the memory means. If it is within the setting range defined by the position information, it is judged that it is the beginning of the program specified by the user and playback is started. If it is outside the setting range, it is judged that it is not the specified program and the cue signal detection operation is performed again. The video tape recorder according to claim 1, wherein the video tape recorder is configured to continue.