JPH0664898B2 - Magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder having a program cueing function.

2. Description of the Related Art When a plurality of programs are recorded on one magnetic tape, it is quite difficult to find the beginning of the above program, but now, in the high speed running mode, the program is recorded at the boundary between the programs. It is considered that this can be facilitated by reading out the existing cue (hereinafter referred to as Cue) signal. Therefore, for example, in a video tape recorder (hereinafter abbreviated as VTR) using a rotary head, a signal of a specific low frequency (about 200 to 300 KHz) that does not affect the video signal, audio signal, and other signals is used as the Cue signal. By recording for several seconds at the boundary between programs, the above Cu can be used even in high-speed driving mode (FF, REW).
It is considered that the e-signal can be read and the cueing will be easy. Also, by dividing the Cue signal into several time zones separated by a specific time interval from the reference of the recording track of the video signal or audio signal originally recorded on the tape, It is considered that the address of the program can be directly read in the high-speed driving mode by recording the address of the program depending on the presence or absence of the cue signal.

Problems to be Solved by the Invention However, in the above configuration, the Cue
Even if the signal is read and the mode is immediately changed to the stop mode and the playback mode is entered, it cannot be stopped immediately due to the inertia of the drive motor of the tape reel base that is running the tape at high speed, and the Cue signal is inevitably recorded. It stops after passing a certain section, and it is not possible to stop exactly at the point where you want to cue. For example, when the cue is performed in the FF mode, the result is that the position of the Cue signal is passed, the cue is performed from the middle of the program, and the program is reproduced from there. When the program is cued from REW mode, it will start playing from the middle of the program immediately before the cued program. In this way, it is expected that cueing will be possible in the high-speed running mode and the time required for cueing will be greatly shortened, but it is not possible to accurately stop and play at the position where the cue signal is recorded. I have a problem.

Also, because the Cue signal is searched for in the high-speed driving mode, the playback time of the detected Cue signal is short, and some noise may cause it to be mistakenly detected as a Cue signal, and the playback may stop and play. It also had the problem of being volatile.

In view of the above problems, the present invention accurately detects the Cue signal by detecting the Cue signal again in the low speed running mode at the Cue signal detected in the high speed running mode, and the position on the recorded tape. The present invention provides a magnetic recording / reproducing device which is accurately stopped and reproduced.

Means for Solving the Problems In order to solve the above problems, the magnetic recording / reproducing apparatus of the present invention is a tape capable of running a magnetic tape for recording or reproducing a signal by a magnetic head at at least two kinds of tape running speeds. The tape traveling speed of the traveling means and the first tape traveling means has a traveling speed higher than the tape traveling speed of the second tape traveling means, and the tape traveling speed is near the first information recorded on the magnetic tape. First detecting means for detecting, by using the first tape running means, second information composed of a signal other than the band of the signal representing the first information, and the first information in the vicinity of the first information. Second detecting means for detecting the third information indicating the absolute address of the information on the magnetic tape by using the second tape running means, wherein the magnetic tape is the first tape running means. Running Then, after the second information is detected by the first detecting means, the magnetic tape is stopped and the magnetic tape is moved by the second tape running means to the running direction of the first tape running means. It is configured such that the magnetic tape is stopped when it is run in the opposite direction and the third information is detected by the second detecting means.

Operation The present invention has the above-described configuration, which causes a shift in the cue position caused by a shift in the stop position due to an abrupt stop from when the magnetic tape is running at high speed, and in a high speed mode.
When the Cue signal is read by mistake due to some noise, it is clear by running the magnetic tape in the direction opposite to the running direction of the magnetic tape in the high speed mode and reading the Cue signal again in the low speed running mode. The contents of the Cue signal can be sufficiently checked to prevent erroneous cueing, and the Cue signal is detected, and after checking the contents, there is almost no deviation of the tape stop position due to the stop from the low speed mode by stopping immediately. Can be stopped exactly at the position of the Cue signal. As described above, the cue can be accurately performed without malfunctioning.

Embodiments A magnetic recording / reproducing apparatus according to embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a relationship between a head and a tape according to an embodiment of the present invention. Heads 1 and 2 are attached to a rotating cylinder 3 and are alternately arranged with respect to a tape 4 running as shown. Record or play back. FIG. 2 shows an example of signals for each head at that time. The recorded / reproduced signals are video signals, audio signals, or both signals.

The Cue signal used in this embodiment is composed of two signals. First, a constant low frequency signal is used as the boundary section signal of the program. This boundary section signal uses a low frequency signal to minimize the azimuth effect of the heads 1 and 2 in order to obtain a reproduction output with a certain level even in the high speed running mode, and the signal can be detected even in reverse azimuth. I am trying. However, the lower the frequency, the smaller the azimuth loss can be made, but since the reproduction output of the head becomes sharply smaller than about 100 KHz, the frequency of the boundary signal is set to about 200 to 300 KHz. The above frequency needs to be a frequency that does not affect the video signal to the audio signal or other signals. Secondly, an address signal indicating the absolute position of each program on the magnetic tape 4 is configured as the Cue signal. For example, this address signal is composed of a frequency band different from the frequency band constituting the program, and indicates the absolute address on the magnetic tape from the combination of information depending on the presence or absence of signals in the frequency band in a plurality of specific time zones. ing.

The Cue signal set in this way is recorded at a boundary between programs for a fixed time (usually 3 to 4 seconds).

Next, the block of the circuit in which the Cue signal is detected will be described with reference to FIG. The signal recorded on the magnetic tape 4 is reproduced by the heads 1 and 2 and passes through the switch 5,
After being amplified by the head amplifier 6, the switch 7 produces a series of signals. Normal video signals and audio signals are demodulated in the video / audio signal processing circuit 8 and output to video and audio through the muting circuit 9. When the Cue signal is reproduced, the Cue signal passes through a bandpass filter (hereinafter abbreviated as BPF) 10 that passes only the frequency band of the Cue signal, is rectified by a rectifying circuit 11, and then integrated by an integrating circuit 12, Through the comparator 13 that is compared according to the level at which the Cue signal is reproduced, the H or L level is shown only during the time when the Cue signal is digitally reproduced. Cue detected by the holding circuit 14 for holding the digitized Cue signal for a certain time
The signal is processed as one Cue signal and input to the system control circuit 15. Then, it is processed by the system control circuit 15, and mode transfer signals such as FF, REW, PB, reverse PB, STOP, etc. are output to the tape running circuit 18, and the tape running means 19 runs the magnetic tape 4. Further, the system control circuit 15 outputs a muting signal to the muting circuit 9 in order to stop the video signal and the audio signal at that time when the Cue signal is being reproduced. A head switching signal is also output to the switch 7.

Next, FIG. 4 shows how to process the detected Cue signal. Heads 1 and 2 are shown as one head in order to facilitate understanding of the relationship in the tape running direction. Usually, it is assumed that the tape 4 is reproduced from the right side to the left side of the drawing with respect to the heads 1 and 2. First, FIG. 4 (a) shows that the magnetic tape 4 was running at a high speed in the FF mode and started to pass through where the Cue signal 16 was recorded. So Cu
As soon as the boundary section signal forming the e signal 16 is detected as described above, a stop signal is output from the system control circuit 15 to the tape running circuit 18, but the stop signal is transmitted and the mode is changed. Due to the fact that it takes a little time for the tape to move and the rotational inertia of the motor running the tape at a high speed, the tape stop position becomes a point where the position of the Cue signal 16 has significantly exceeded, as shown in Fig. 4 (a), and the cue is restarted. I want to stop in the middle of program 17. In addition, the stop position is usually shifted due to the tape speed of high-speed running in FF mode. Then, in order to correct the deviation shown in FIG. 4 (a), the system control circuit 15 outputs a signal for setting the reverse reproduction mode in order to run the magnetic tape 4 in the reverse direction in the low speed mode. Then, as shown in FIG. 4 (c), when the signal passes through the Cue signal section 16 again, the address signal forming the Cue signal is detected through the circuit block described above. When the address signal is detected and the detection signal is input to the system control circuit 15, the system control circuit 15 immediately outputs a signal to enter the stop mode, and the magnetic tape 4 is stopped. Further, if the deviation of the stop position shown in FIG. 4 (a) is small and it is stopped where the Cue signal 16 is recorded,
The system control circuit 15 once shifts to the reverse reproduction mode, but at that moment, since the address number is detected, it immediately becomes the stop mode. That is, the magnetic tape 4 is stopped without running. As described above, the cueing is completed, and as shown in FIG. 4D, the program 17 can be reproduced more accurately than where it is recorded. The above processing is shown in the flowchart of FIG.

Next, a brief description will be given of the case of cueing from the REW mode. First, as shown in FIG. 4 (e), when the cue signal portion 16 is passed, a boundary section signal is detected, and as in the FF mode, FIG. As shown in (f), the magnetic tape 4 stops after passing considerably. Therefore, this time, in order to correct the deviation, the vehicle is driven in the low speed mode in the reproduction direction, the address signal is detected again, the stop mode is entered, the cueing is completed, and the Cue signal 16 is recorded as shown in FIG. However, it can be reproduced more accurately. The above processing is shown in the flowchart of FIG.

Further, even if the recording / reproducing is performed on a plurality of tracks on the same tape, the cue signal can be detected as described above by the signal extracted only from the track, and the cue can be accurately performed.

Also, the Cue signal is detected again in the low speed mode (playback or reverse playback), but even if the low speed mode at this time is several times the standard playback speed, it is possible to find the cue signal with sufficient accuracy. is there.

In addition, the Cue signal is divided into multiple C
If the program number is digitally represented by the presence or absence of the Cue signal in each time zone, even if the program number of the Cue signal cannot be detected completely in the high speed mode, the By detecting the Cue signal, the cue can be accurately performed.

As described above, according to the present invention, the boundary section signal recorded at the boundary of the program is detected in the high speed mode, and then the address number is detected again in the low speed mode. You can get the excellent effect of being able to be accurate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a relationship between a head and a tape of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a signal configuration diagram in the apparatus, and FIG. 3 is the apparatus. FIG. 4 is a block diagram showing a reproducing circuit in FIG. 4, FIG. 4 is a schematic diagram showing a positional relationship between a tape and a head for detecting a Cue signal of the device, and FIGS. 5 and 6 are flow charts showing an operation of the device. 1,2 ...... Head, 4 ...... Magnetic tape, 10 ...... Band pass filter, 11 ...... Rectifier circuit, 12 ...... Integration circuit, 13 ......
Comparator, 14 ... Holding circuit, 15 ... System control circuit, 18 ... Tape running circuit, 19 ... Tape running means.

Claims (1)

[Claims] 1. A tape running means capable of running a magnetic tape for recording or reproducing a signal by a magnetic head at at least two kinds of tape running speeds, and a tape running speed of a first tape running means is a second tape running speed. The second information having a traveling speed higher than the tape traveling speed of the means and formed by a signal other than the band of the symbol representing the first information in the vicinity of the first information recorded on the magnetic tape. The first tape detecting means for detecting using the first tape moving means, and the third information indicating the absolute address of the first information on the magnetic tape in the vicinity of the first information are transferred to the second tape. A second detection means for detecting using a means,
When the magnetic tape is run by the first tape running means, after the second information is detected by the first detecting means, the magnetic tape is stopped and the magnetic tape is moved by the second tape. The tape traveling means is configured to cause the tape traveling means to travel in a direction opposite to the traveling direction, and when the third information is detected by the second detecting means, the traveling of the magnetic tape is stopped. Characteristic magnetic recording / reproducing device.