KR970011125B1 - Tracking signal of vcr recording and reproducing method and the circuit - Google Patents

Abstract

VCR using an ATF(i.e., auto track finding) method differently record a pilot signal on a track upper part and a track lower part when the user sets a specific index during 8mm VCR recording, detects the pilot signal differently recorded during a reproduction, and searches a set position at a high-speed. A VCR tracking signal record reproduction method divides a predetermined track into two parts(i.e., upper and lower tracks) at a desired reproduction point; records a pilot signal on one track between the upper and lower tracks according to a prior original order; records a pilot signal on the other track according to another order different from the prior original order; forms a record format of a tape; compares the pilot signal recorded on both the upper track and the lower track at a plurality of points during a reproduction mode, and detects a signal pattern; and searches a set position by detecting a specific pattern.

Description

Tracking signal recording and reproducing method of V-Cal and its circuit

1 is an exemplary view showing an ATF recording format.

2 is a block diagram of a tracking signal recording and reproducing circuit of the present invention.

3 (a) and 3 (b) are exemplary diagrams of a recording format according to the present invention.

4 is a trajectory diagram of the head in the forward search.

5 is a trajectory diagram of the head during the reverse search.

6 is a waveform diagram of a tracking signal according to a head trajectory.

7 is a waveform diagram of a tracking signal in the forward search of FIG.

FIG. 8 is a waveform diagram of a tracking signal in the forward search of FIG.

9 is a waveform diagram of a tracking signal in the reverse search of the method shown in FIG.

FIG. 10 is a waveform diagram of a tracking signal in a reverse search of the method shown in FIG.

* Explanation of symbols for main parts of the drawings

1: Microcomputer 1-1: Analog-to-digital converter

2: tracking signal generating unit 3: recording amplifier unit

4: drum 5: play amplifier

6 filter unit 7 tracking signal comparison unit

HD: Head

The present invention relates to a V-CAL using a tracking signal (ATF) method, in particular, when the user wants to set a specific index when recording in 8mm V-Cal, the pilot signal is recorded differently on the upper and lower tracks. The present invention relates to a tracking signal recording and reproducing method of V-CAL that seeks a set position at high speed in response to detecting this signal during reproduction.

However, currently used 1 / 2-inch (VHS) home VRs and video cameras have a Video Index Search System (VISS) function to search for a desired program at high speed, but the VISS function has not been applied to 8mm VRs.

The reason is that the recording method of 1/2 inch VRC tape is different from the recording method of 8mm VRC tape, so the control signal, which is audio signal, video signal, and tracking signal, is located at the fixed position. Although recorded separately, the 8mm VRT tape is recorded with a mixture of tracking signals (ATF: Auto Track Finding), which serve as audio signals, video signals, and control signals.

The 8mm VCR records a pilot signal, which is a tracking signal, mixed with audio and video signals using an ATF (Auto Track Finding) method and recorded on a track. As shown in FIG. 1, the frequency of the pilot signal is 6.5f for each track. _The signals obtained by differently recording _H , 7.5f _H , 10.5f _H and 9.5f _H and passing them through the filter during reproduction are used as tracking information.

The VISS function applied to 1 / 2-inch V-CAL records the control signal recorded at the desired playback start point with a different duty ratio than the normal control signal, and then finds a point where the duty ratio of the control signal is recorded differently during playback. By starting playback from that point, the desired playback start point can be found quickly, but the 8mm V-CAL has no control signal area and cannot implement the VISS function.

Therefore, 8mm VRC has a problem that not only consumes a lot of time but also inconveniences the user by scanning each program in turn when looking for a desired program among a plurality of programs.

The present invention divides a predetermined track into upper and lower portions at a point to be reproduced at the time of recording in order to improve such a conventional problem, and then records a pilot signal on the lower track in the same manner as in the conventional order. The track is recorded in a different order from the conventional one, and the pilot signal recorded at the top and bottom of the track is compared with the reference signal during playback to find a specific pattern recorded at a set position by sampling the detected signal pattern at a plurality of points. A method of recording and reproducing a tracking signal of V-CAL capable of finding the set position at high speed, and a circuit thereof, are described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram of the tracking signal recording and reproducing circuit of the present invention. As shown in FIG. ₂ , the tracking signal generator 2 generates a specific pilot signal according to the selection signals SL ₁ and SL ₂ . And a recording amplifier unit 3 for outputting the output of the tracking signal generator 2 to a head HD mounted on the drum 4 by amplifying a predetermined number of levels mixed with the video signal and the audio signal, and the head HD. A reproduction amplifier unit 5 for amplifying a detection signal of the signal to a predetermined level and outputting the filter unit, and a filter unit for separating the tracking signal ATF from video and audio signals from the output signal of the reproduction amplifier unit 5 ( 6) and a tracking signal comparison unit 7 for generating a voltage difference Err corresponding to the frequency difference by comparing the reference signal generated by the selection signals SL ₁ and SL ₂ with the output signal of the filter unit. Control the overall operation of the system and output the tracking signal comparator 7 during playback. rr) is digitally converted by the analog-to-digital converting section 1-1, and compared with a set value, and is configured as a microcomputer 1 that controls a capstan motor that performs tape travel so as to find a desired track position in a search operation.

The operation and effects of the present invention configured as described above will be described in detail with reference to FIGS. 3 to 10.

The 8mm BC uses the tracking signal (ATF) as the capstan phase control signal for driving the track. The tracking signal (ATF) is applied to 6.5f _H , 7.5f _H , 10.5f _H and 9.5 for each track (CH _{1 to} CH ₄ ). pilot signals f _H (f ₁ ~f ₄₎ a selection signal (SL _1), sequentially recorded by the (SL ₂₎ and the adjacent tracks and the car are shown the frequency of f _H or 3f _H.

At this time, the frequency of the reference signal selected by the selection signals SL ₁ and SL ₂ and the adjacent tracks is compared, and when the component of 3f _H is large, the difference is larger than 2.5V, and when the component of f _H is large, it is smaller than 2.5V.

If the f1 track and the reference signal is the f1 signal as in the example of FIG. 3, the waveform of the difference Err is shown in FIG. 3 when the head trajectory is as shown in the figure.

Therefore, if the order of the pilot signals to be recorded is recorded differently, the waveform of the difference Err obtained during reproduction appears differently.

Using this, the present invention implements the VISS function by dividing a portion of a predetermined track to be indexed into the upper and lower parts, recording the data in the format shown in FIG.

That is, in order to record the pilot pilot signal on the upper part of the track and the pilot pilot signal on the lower part of the track so that the detection level of the pilot signal is changed during the high-speed search, the format is formed in the order as shown in FIG. The search pilot signal can be recorded by setting the area, and the size of the area division is half (1/2), which can be changed depending on the size or the search speed.

When the user selects the index display function at the portion to which the index is to be inserted, the tracking signal generator 2 causes the four pilot signals f _{1 to} f by the selection signals SL ₁ and SL ₂ of the microcomputer ₁ . ₄ ), the recording amplifier unit 3 mixes with the audio and video signals, amplifies a predetermined level, and records the tape on the head HD mounted on the drum 4.

On the other hand, if the search function is set in order to find a desired part for playback by selecting the playback mode, the signal detected by the head HD mounted on the drum 4 is tracked in the playback amplifier unit 5 and the filter unit 6. After the signal ATF is separated, it is amplified by a predetermined level and input to the tracking signal comparing unit 7 and compared with the reference signals generated by the selection signals SL ₁ and SL ₂ of the microcomputer ₁ . The frequency difference signal Err is digitally converted by the analog-to-digital converter 1-1 of the microcomputer 1.

Accordingly, the microcomputer 1 calculates the output of the analog-digital converter 1-1 to determine the driving state of the head HD, and then performs tracking control.

When the pilot signal for index search is recorded as shown in FIG. 4, the search speed at which the index is searched is searched at the forward speed (4n + 1 times) or the reverse speed (4n-1 times) as shown in FIGS. (n is 1, 2, 3,…)

At this time, CH ₄ teulraek when the reference signal f ₁ days to obtain regularity of the information CH ₁ track, f when _two days CH ₂ track, f when ₃ days CH ₃ tracks, f is ₄ by a predetermined sampling time, a Capstan control is performed so as to be located in front of the head switching time.

Accordingly, the waveform characteristics of the tracking signal ATF appear as shown in FIGS. 7 to 10 when 'n' is '1'.

The reason is that when divided into four sections a, b, c, and d as shown in FIGS. 5 to 6, the sections a and b are sections in which control pilot signals are recorded. The waveforms of the tracking signals (ATF) are the same, and in the tracks c and d, the search pilot signals are recorded in the tracks with indexes, and the control pilot signals are recorded in the tracks without indexes. Appears different.

In this case, if the waveform of the tracking signal is inverted when the reference signals are f ₂ and f ₄ , the tracking signal has a constant pattern regardless of the reference signal. FIGS. 7 and 9 show the recording format of FIG. And FIG. 6 shows waveforms of the tracking signal (ATF) in the forward and reverse search, and FIGS. 8 and 10 show the recording format of FIG. As a waveform diagram of the tracking signal ATF, a time point t ₁ is a sampling time point for phase control of a capstan and a time point t ₂ is a sampling time point for confirming that normal control is performed.

Here, if normal control is being performed, sampling is performed at the time points t3 and t4 to determine the search lock, and the value obtained is digitally converted and compared with a threshold value of about 2.2V to 2.8V. 0 "and if the reference signal is f ₂ , f ₄ , the level is reversed.

Therefore, when the above operation is performed, all waveforms of FIGS. 7 to 10 are obtained at the time points t1, t2, t3, and t4 as shown in the following table.

(Inspection of tape section without index)

(For tape segments with indexes)

This operation prevents chattering as it repeats, and after confirming the existence of the search signal and determining the existence of the search signal, it is set at a low double speed (1 or 2 times speed). In the reverse direction, normal playback is performed by moving to the first track on which the index signal is recorded.

According to the present invention, the threshold voltage may be adjusted to utilize more information, not just two pieces of information '1' and '0'.

As described in detail above, the present invention has an effect that the user can search at a high speed when the user wants to find a specific part by manipulating the pilot signal itself to display the specific part without implementing hardware, thereby providing convenience to the user.

Claims (2)

In the recording mode, a predetermined track is divided into upper and lower parts at the point where playback is desired, and a pilot signal is recorded in one of the upper and lower tracks in the same order as before, and the other track is In order to detect a specific pattern by detecting a signal pattern by comparing the reference signal with the pilot signal recorded on the track and the lower part at a plurality of points in the playback mode, the recording format of the tape is recorded in a different order. The tracking signal recording and reproducing method of V-C, characterized by finding a setting position. In the recording mode, a tracking signal generator 2 for generating a specific pilot signal in accordance with the selection signals SL ₁ and SL ₂ and the output of the tracking signal generator 2 are mixed with a video signal and an audio signal. A recording amplifier unit 3 for recording to tape through the head HD, a reproduction amplifier unit 5 for amplifying the detection signal of the head HD at a constant level during reproduction, and an output of the reproduction amplifier unit 5 The filter unit 6 which separates the tracking signal ATF from the signal, and the reference signal generated by the selection signals SL ₁ and SL ₂ and the output signal of the filter unit 6 are compared to the frequency difference. Outputs the selection signals SL ₁ and SL ₂ in accordance with the tracking signal comparison unit 7 for generating a corresponding voltage difference Err and a command for index display / search in controlling the overall operation of the system. In the playback mode, the output Err of the tracking signal comparison unit 7 is digitally converted by the analog / digital converter 1-1. And a microcomputer (1) for controlling a capstan mode in which tape travel is performed to find a desired track position in a search operation after comparing with a set value.