JPH02240852A - Information program searching circuit device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify the program search and to attain highly accurate retrieval position by recording a prescribed tracking signal on the prescribed track upon normal recording and detecting the tracking signal upon reproduction for the program searching operation. CONSTITUTION:When a program searching switch 3 is operated in the case of recording a video signal, a pilot signal generating circuit 5 sends a pilot signal with a prescribed frequency for a prescribed time band and the signal is recorded onto a prescribed area of a track of a video tape. In the case of fast forward reproduction, when the program searching switch is operated, a reference pilot signal is sent from the pilot signal generating circuit 5, and ATF circuit 2 selects a pilot signal relating to the reference pilot signal from the reproduced pilot signal and generates a tracking signal and sends it to a sample and hold circuit 7 via an amplifier 6 and a system control microcomputer 4 uses a control signal sent from a DELTAFa detection deciding circuit 8 to send a control signal to stop the video tape to the capstan control section.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information cueing circuit device for a magnetic recording/reproducing device.

[Prior art and its problems] A pilot signal whose frequency is cyclically changed for each track is recorded along with the video signal on so-called tracks of a video tape on which the video signal is recorded, and the pilot signal reproduced from these tracks during playback is The ATF method detects a signal component that is the difference in frequency between the reference pilot signal corresponding to the pilot signal of each track, and performs tracking control of the magnetic head based on a tracking error signal obtained from this signal component. A tracking control method called JP-A-63136350 is disclosed, for example. This ATF method is used in the so-called 8mm video tape recorder (hereinafter referred to as VTR).
used in

This type of ATF system is used to record and play back data using four heads using a particularly small cylinder.
In an 8mm VTR with a head sequential recording system, the video tape is run at a faster speed than the normal playback speed to play back video information, so-called fast forwarding and rewinding, and so-called cueing, which allows the operator to quickly search for the video information he or she wants to see. Conventionally, when doing this, the operator has used a counter that numerically displays the running distance of the videotape, or has searched for the video desired by the operator while watching the video being played back and displayed. This kind of operation is troublesome for the operator, such as having to remember the counter value of the cue section, and also has problems in that it is difficult to cue the video information section desired by the operator, and the accuracy of the search position is poor. There is.

The present invention has been made to solve these problems, and it is an object of the present invention to provide an information cueing circuit device for a magnetic recording/reproducing device that can search with high accuracy a portion of video information specified at the time of recording with a simple operation. purpose.

[Means for Solving the Problems] The present invention is a magnetic recording/reproducing device using an ATF method in which a control signal for controlling tracking of a magnetic head and video information are recorded on the same track, and the present invention is a magnetic recording/reproducing device using an ATF method in which a control signal for controlling tracking of a magnetic head and video information are recorded on the same track. a recording means for recording a predetermined tracking signal in a predetermined area of the tracker; a detecting means for detecting the tracking signal reproduced during a cueing operation; and a cueing switch for activating the recording means or the detecting means. It is characterized by having

[Operation] When the operator operates the cue switch, the recording means records a tracking signal in an area of the track of the magnetic recording medium that is not used during normal reproduction. The detection means reproduces and detects the tracking signal recorded by the recording means during the cueing operation when the operator operates the cueing switch.

[Embodiment] In FIG. 1 showing an embodiment of the present invention, A to D are magnetic heads installed on a rotating cylinder of an 8 mm VTR, and the installation positions of magnetic heads A to D on the rotating cylinder are as follows. As shown in the figure,
The content is similar to that disclosed in Publication No. 6350. These magnetic heads A to D are connected to an ATP circuit 2 via a switch circuit 1 for selecting a magnetic head when recording or reproducing video information on a video tape.

The ATF circuit 2 records a pilot signal having a frequency of rt to f4 on a video tape together with video information during recording, and supplies signals corresponding to the frequency of the pilot signal to be reproduced and each pilot signal during playback. Differences ΔFa and ΔF from the frequency of the reference pilot signal
This is a known circuit for generating tracking control of a magnetic head based on the differences ΔPa and ΔFb.

Here, between ΔPa, ΔFb and fl to f4, ΔPa = lf l - r 21 = lr 3 - r 4
, AF'b = lf 2-f 31 = lf 1-441
There is a relationship between

In addition, the switch circuit 1 and the ATF circuit 2 are disclosed in Japanese Patent Application Laid-Open No. 1986-
It has a circuit configuration similar to that disclosed in Japanese Patent No. 136350, and the output side of the ATF circuit 2 is connected to a capstan speed control section (not shown) for driving a video tape.

The cueing switch 3, which is operated by the operator to change the operation mode of the VTR when recording the video information portion that the operator desires to cue on the videotape or cueing the video information, is a cueing switch 3 in the circuit. It is connected to a pilot signal generation circuit 5 via a system control microcomputer 4 that controls the operation of the components. The other output side of the system control microcomputer 4 is directly connected to the ATF circuit 2 and also to the sample and hold circuit 7. The pilot signal generation circuit 5 generates a pilot signal recorded for each track of a videotape on which video information is recorded, a reference pilot signal corresponding to the pilot signal recorded on each track, and an A during recording.
This circuit generates a control signal that controls the operation of the TF circuit 2, and the output side of the pilot signal generation circuit 5 is A'I.
” Connected to F circuit 2.

The output side of the ATF circuit 2 is connected to the sample-and-hold circuit 7 via the capstan speed controller described above and an amplifier 6 that amplifies the signal formed by the difference ΔPa or ΔFb. The sample and hold circuit 7 is a circuit that extracts and holds the peak levels of the differences ΔPa and ΔFb, and the output side of the sample and hold circuit 7 is a ΔPa detection circuit that determines whether the peak level of the difference ΔPa has been detected for a set time or longer, for example. The output side of the ΔFa detection and discrimination circuit 8 is connected to the system control microcomputer 4.

The operation of the cueing circuit device configured as described above will be described below.

When performing normal video information recording, magnetic heads A to D are switched according to the magnetic head switching signal shown in FIG. 3a, and as shown in FIG. ,..., the frequency is f1%f2, f3, r4, along with video information on each track.
Pilot signals in the order fl, f2, . . . are recorded. Then, during playback, as mentioned above, the frequency difference Δ
Tracking of the magnetic head is controlled by Pa or ΔFb.

Next, the operation of this device when performing a cueing operation will be described below. In a recording mode for recording video information on a videotape, video information of a portion to be cued is recorded, for example, at time t shown in FIG. 3.

When the operator operates cue switch 3,
The scanning time of one track is divided into three times, X hours, 7 hours, and A pilot signal consisting of the following signals is sent out from the pilot signal generation circuit 5. That is,
As shown in FIG. 3d, for example, a pilot signal of frequency f1 is recorded in the seven time periods of all the tracks during which the cueing operation is instructed, and a pilot signal of frequency f1 is recorded in the X time period. The pilot signal generation circuit 5 outputs pilot signals of each frequency to A so that the signals are recorded in order.
The signal is sent to the TF circuit 2.

Therefore, as shown in FIG.
A pilot signal with frequencies [l5f2, ``3, r4, fl, ...'' is recorded on both sides of the center of the track.
Pilot signals are recorded in this order. Note that the several millisecond section at the center of the track is not necessary for tracking control during normal playback. Further, as described above, the time during which the frequency is recorded is controlled by the system control microcomputer 4 to a predetermined time.

A case in which a videotape in which a desired section is recorded in this manner is played back while fast-forwarding or rewinding will be described below.

In this embodiment, the running speed of the videotape in both fast forward playback and rewind playback is five times the running speed of the videotape during normal playback. In addition, in this embodiment, as described above, the frequency recorded at the center of the track is set to rt, and the frequency ΔFa is detected in order to detect the cue portion, so that the aforementioned ΔFa=1f
From the relationship l-r21, the frequency of the reference pilot signal sent from the pilot signal generation circuit 5 is f2.

When performing cue operation during fast forward playback, press cue switch 3
When is operated, a control signal sent from the system control microcomputer 4 fixes the frequency of the reference pilot signal sent from the pilot signal generation circuit 5 to r2.

Then, each of the magnetic heads A to D diagonally scans five tracks on the video tape as shown by arrows Z in FIG. Send.

At this time, as is clear from FIG. 4, each magnetic head always scans the center of the track, that is, the area where the frequency f1 is recorded, once in one scan. Therefore, AT
A pilot signal of frequency fl is supplied to the F circuit-2 at regular intervals. And the ATF circuit 2 is
fl supplied.

Select a pilot signal with a frequency rt related to the frequency r2 of the reference pilot signal from the pilot signals of each frequency such as 12, etc., and create a tracking signal having a frequency ΔPa from the reference pilot signal, a pilot signal with a frequency "l", This signal is sent to the sample-and-hold circuit 7 via the amplifier 6.As mentioned above, since the signal of frequency rt is supplied to the ATF' circuit 2 at regular intervals, the tracking signal is sampled at regular intervals. It is sent to the hold circuit 7. Therefore, the sample hold circuit 7
sends the peak level of the supplied tracking signal to the ΔPa detection and discrimination circuit 8, and the ΔPa detection and discrimination circuit 8
determines whether a ΔPa signal of a certain level or higher is detected several times or more in succession, and sends a control signal to the system control microcomputer 4 if the above condition is met. When the system control microcomputer 4 is supplied with the control signal, the system control microcomputer 4 causes the capstan speed control section to stop running the video tape,
A control signal such as setting the playback speed to normal is sent out.

By recording a pilot signal of a predetermined frequency in the center of a videotape track during recording in this way, a signal of a predetermined frequency is detected at regular intervals during cueing operations, making cueing easier. It is possible to search with high precision. After the cue portion is searched, various operations such as stopping the running of the videotape or shifting to normal playback mode are performed.

Also, during rewind playback, the cue of the video information is searched in the same manner as described above.

In the above-described embodiment, the frequency of the pilot signal recorded in the center of the track of the videotape is fl,
Although the frequency of the reference pilot signal is set to 2, it is not limited to this and may be a combination of frequency r3 and frequency f4. Also, a combination of frequency 12 and frequency r3 or a combination of frequency fl and frequency r4 may be used. However, in this case, the ATP circuit 2 sends out a signal having a frequency of ΔFb, and the circuit to which the sample and hold circuit 7 is connected becomes a ΔFb detection/discrimination circuit.

In addition, although the running speed of the videotape during fast-forward playback and rewind playback was set to 5 times the normal speed, this device can be applied regardless of the magnification as long as the videotape running speed is an odd number times the normal speed. can.

[Effects of the Invention] As described in detail above, according to the present invention, the operator only needs to operate the cueing switch, and during the cueing operation, the detection means detects a predetermined tracking signal recorded by the recording means at the time of recording. By detecting this, it is possible to search with high accuracy the video information portion specified during recording with a simple operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the information cueing circuit device of the present invention, FIG. 2 is a plan view of a rotating cylinder to which the magnetic head used in FIG. 1 is attached, and FIG. FIG. 4 is a time chart showing the operation of the information cueing circuit device, and is a diagram showing tracks recorded on a videotape by the information cueing circuit device of the present invention. First cause 2... ATF circuit, 3... cue switch, 4...
・System control microcomputer, 5...
・Pilot signal generation circuit, ΔPa detection discrimination circuit. Figure 2

Claims (1)

[Claims] (1) A magnetic recording/reproducing device using the ATF method in which a control signal for controlling tracking of a magnetic head and video information are recorded on the same track, and a predetermined tracking signal is recorded in a predetermined area of the track during normal recording. A magnetic recording and reproducing device comprising: a recording means for detecting the tracking signal; a detecting means for detecting the tracking signal reproduced during a cueing operation; and a cueing switch for activating the recording means or the detecting means. information cue circuit device.