JPH04291049A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enlarge a detection area by detecting a tracking difference by means of a tracking difference detection pilot reproduced as an adjacent crosstalk signal from plural number of rotating magnetic multi-heads. CONSTITUTION:Rotating magnetic multi-heads 2 and 3 have the same azimuth angle and conducts reproducing while overlapping with each other in the same recording signal track. Pilot amplitude detectors 11 and 12 detects the amplitude level of the tracking difference detection pilot reproduced from the magnetic heads 2 and 3 and outputs it to an electric power differential circuit 13. The differential circuit 13 compares the electric power difference between the outputs of the pilot amplitude detectors 11 and 12 and outputs a tracking difference signal. Thus, the reproducing width of the adjacent tracks can be increased and accordingly, the detection area can be enlarged.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus for recording and reproducing signals in response to narrower tracks.

0002

[Prior Art] Conventionally, in magnetic recording and reproducing devices used in home VTRs and the like, recording patterns are recorded without guard bands to increase recording density, and azimuth recording is performed to reduce crosstalk between adjacent tracks. ing. During playback, a playback head with a head width wider than the track pitch is used to take into account deviations due to tracking curvature.

[0003] Tracking error detection involves recording a control track in the longitudinal direction of the magnetic tape using pulses indicating the rotational phase of the head drum as a control signal, in addition to a video track for recording and reproducing video signals. This is done by comparing the phase of the reproduced control signal and the phase of the rotation pulse of the head drum. (For example, supervised by Ryo Takahashi, VTR technology (Japan Broadcasting Corporation)).

On the other hand, in the case of 8 mm video, four low frequency pilots with different frequencies are set, and the low frequency pilots are frequency-multiplexed onto the video signal one by one for each video track and recorded azimuthally without a guard band. teeth,
Using a playback head with a head width wider than the track pitch,
Two low frequency pilots recorded on both adjacent video tracks are detected as crosstalk from adjacent video tracks, and a tracking error is detected by comparing the power difference between the two low frequency pilot signals. (For example, Journal of the Television Society Vol. 44, No.
．． 9 pp. 1170-1174)

[0005]

[Problems to be Solved by the Invention] However, in the conventional playback head, as the track pitch becomes narrower, the playback signal output decreases, and the ratio of the head width to the track pitch also increases, so that crosstalk between adjacent tracks occurs. The influence of talk cannot be ignored, and the necessary signal-to-noise ratio (hereinafter referred to as S/N) cannot be obtained.

Furthermore, as the track pitch becomes narrower, there is a risk of reproducing adjacent tracks recorded at the same azimuth, and in order to reduce the effects of adjacent crosstalk, the head width is also made wider than necessary. I can't.

[0007] Therefore, even a slight track curvature has a large influence on the reproduced signal output, making it difficult to maintain tracking margin.

Furthermore, with the conventional method using control tracks, the linearity of the video track cannot be detected, and it is extremely difficult to improve the tracking error detection accuracy.

[0009] In view of this point, the present invention
The object of the present invention is to provide a magnetic recording/reproducing device with high /N, and also to provide a magnetic recording/reproducing device that is resistant to track bending.

0010

[Means for Solving the Problems] The invention as claimed in claim 1 is a magnetic recording and reproducing apparatus that records and reproduces a pilot for tracking error detection along with a main signal on diagonal tracks on a magnetic tape using a rotating magnetic head, which are identical to each other. two multi-rotation magnetic heads having an azimuth angle and reproducing the same recorded signal track in an overlapping manner; two pilot amplitude detectors for detecting the amplitudes of the pilots from the two multi-rotation magnetic heads; The present invention is a magnetic recording/reproducing device characterized by comprising a difference in pilot amplitude detection output and a power difference for detecting a tracking error.

[0011] The inventions of claims 2, 3, and 4 are as follows:
In addition to the tracking error detection according to the first aspect, a main signal reproduction configuration is described.

[0012] The invention of claim 2 is a magnetic recording/reproducing system in which the main signal recorded on the magnetic tape is composed of a digital signal whose minimum unit is one synchronization block consisting of a synchronization pattern, ID data, data, and an error correction code. A device,
The main signal is reproduced by two multi-rotation magnetic heads having the same azimuth angle and reproducing the same recording signal track in an overlapping manner, and two equalizers, two synchronization detections, and two error number detections are used to reproduce the main signal. It consists of digitally decoding the main signals reproduced from two multi-magnetic heads, selecting the one with the smallest number of errors for each synchronized block whose ID data matches, and selecting a channel for outputting the two decoded signals. This is a magnetic recording/reproducing device characterized by the following.

The invention according to claim 3 reproduces the main signal recorded on the magnetic tape with two multi-rotation magnetic heads having the same azimuth angle and reproducing the same recording signal track in an overlapping manner, The magnetic recording and reproducing apparatus is characterized in that it comprises a delay for aligning the time axes of the two reproduced signals, and a signal addition for adding the two reproduced signals whose time axes have been corrected.

[0014]

According to the above-described structure, the invention according to claim 1 has a tracking error reproduced as an adjacent crosstalk signal from two multi-rotation magnetic heads having the same azimuth angle and reproducing the same recording signal track in an overlapping manner. Since the tracking error is detected using a detection pilot, it is possible to widen the adjacent track reproduction width and expand the detection area compared to the conventional case of using one rotary magnetic head.

[0015] The invention according to claim 2, in addition to the above-mentioned claim 1, switches the rotary magnetic heads that are reproducing the outputs of the two multi-rotary magnetic heads according to the number of errors.
The apparent reproduction width of the rotating magnetic head can be increased without being affected by adjacent crosstalk or adjacent adjacent objects.

[0016] The invention according to claim 3, in addition to the above-mentioned claim 1, corrects the time axis and selects two multi-rotation magnetic heads in accordance with the level of reproduction output in the analog signal domain. The apparent reproduction width of the rotating magnetic head can be increased without being affected by adjacent crosstalk or adjacent adjacent objects.

Furthermore, the reproduction signal output is switched during the edit gap period provided in the main signal, thereby preventing deterioration of the video signal due to signal switching.

Furthermore, since the rotary magnetic head is selected in the analog signal area, the circuit scale can be reduced compared to the invention of claim 2.

[0019] In addition to the above-mentioned claim 1, the invention according to claim 4 improves the SN of the main signal because the signals reproduced from the two multi-rotation magnetic heads are added with the time axis corrected. be able to.

[0020]

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 a main part of a magnetic recording/reproducing apparatus according to an embodiment of the invention according to claims 1 and 2.

Reference numeral 1 denotes a magnetic tape on which a pilot for tracking error detection is recorded together with the main signal. 2 and 3 are two multi-rotation magnetic heads for reproducing signals recorded on the magnetic tape 1.

Here, the magnetic tape 1 and the two multi-rotary magnetic heads 2 and 3 are arranged as shown in FIG. 2.

That is, track 1, track 2, and track 3 have tracking error detection pilots f1 and f2.
, f3 are recorded together with the main signal, and the multi-rotary magnetic heads 2 and 3 have the same azimuth angle (in the case of (Fig. 2), the same azimuth angle as track 2), and the same recording signal track ((Fig. 2), the same azimuth angle as track 2). ), the track 2) is arranged so as to be played overlappingly.

The main signal recorded on the magnetic tape 1 is a digital signal as shown in FIG. 3(a), and the minimum unit of the data area is a synchronization pattern as shown in FIG. 3(b). It is assumed that one synchronization block consists of ID data, data, and error correction code.

Now, returning to (FIG. 1), the reproduced signals reproduced from the multi-rotary magnetic heads 2 and 3 are transmitted to the equalizer 4,
5 and is output to pilot amplitude detectors 11 and 12.

Since the multi-rotary magnetic heads 2 and 3 are arranged as described above (FIG. 2), the tracking error detection pilot reproduced as adjacent crosstalk from the multi-rotary magnetic head 2 during reproduction is f1. The tracking error detection pilot reproduced from the multi-rotation magnetic head 3 as adjacent crosstalk is f
2 is played.

Therefore, in the pilot amplitude detection 11, the amplitude level of the tracking error detection pilot f3 reproduced from the multi-rotation magnetic head 3 is detected, and the power difference 1 is detected.
Output to 3.

Further, in the pilot amplitude detection 12, the amplitude level of the tracking error detection pilot f1 reproduced from the multi-rotation magnetic head 2 is detected, and the power difference 13 is detected.
Output to.

The power difference 13 compares the power difference between the outputs of the pilot amplitude detectors 11 and 12, and outputs a tracking error signal.

Here, since the multi-rotary magnetic heads 2 and 3 are arranged as shown in FIG. It has expanded compared to the case of .

[0032] Therefore, the detection area can be expanded. In addition, as shown in FIG. 7, the delay 41 corrects the relative time axis deviation between the multi-rotation magnetic heads 2 and 3, and the addition 42 adds the output of the delay 41 and the output of the multi-rotation magnetic head 3. If the tracking error is detected by outputting the output to the pilot amplitude detectors 11 and 12 (FIG. 1),
Since the multi-rotary magnetic heads 2 and 3 are arranged as shown in FIG. 2, the tracking error detection sensitivity characteristics can be made steeper and the detection sensitivity characteristics can be improved.

Now, returning to (FIG. 1), the reproduction signal reproduced from the multi-rotation magnetic heads 2 and 3 is transmitted to the equalizer 4.
, 5.

The equalizers 4 and 5 correct the frequency characteristics of the inputted digital signal, which is the main signal, and output the corrected signal to the synchronization detectors 6 and 7.

In synchronization detection 6 and 7, the synchronization pattern and ID
The data is detected and output to the error detection units 8 and 9 in units of the smallest unit of synchronization block.

The error detection units 8 and 9 detect the number of errors per synchronization block, which is the minimum unit, and output the detected number to the channel selection unit 10.

In channel selection 10, the number of errors in one synchronous block with matching ID data addresses is compared, and the synchronous block with the least number of errors is selected and output.

Therefore, as mentioned above, if the output of the multi-rotary magnetic heads 2 and 3 is selected, a rotary magnetic head with a good on-track condition will be selected, and as shown in FIG. 2, the apparent The head width of the rotating magnetic head is MT
This is equivalent to w, and the tracking margin can be improved.

In addition, as mentioned above, since a multi-rotation magnetic head is selected, even if one multi-rotation magnetic head reproduces an adjacent track, a good multi-rotation magnetic head is selected, so that the multi-rotation magnetic head is read from the adjacent adjacent track. Not affected by

[0040] Also, the influence of adjacent crosstalk (Fig. 2)
Since it is determined by the head width of one multi-rotation magnetic head shown in
It does not become a factor that deteriorates N.

Next, (FIG. 4) shows a block diagram of a main part of a magnetic recording/reproducing apparatus in an embodiment of the invention according to claims 1 and 3.

[0042] Magnetic tape 1, multi-rotation magnetic head 2,
3 is the arrangement shown in (Fig. 2). However, magnetic tape 1
The recording format of is shown in (Figure 5).

That is, the main signals recorded in one track are digital signals (audio signal, video signal, and control signal), and a first edit gap and a second edit gap are provided at the boundaries of each data. .

Next, returning to (FIG. 4), the multi-rotation magnetic heads 2, 3, pilot amplitude detection 11, 12, power difference 1
3 is the same as the configuration described above (FIG. 1).

Next, the delay 20 delays the reproduced signal output from the multi-rotary magnetic head 2 and corrects the time axes of the multi-rotary magnetic heads 2 and 3 to make them the same time axes.

Next, in the signal selection 21, the output level of the output of the delay 20 and the output of the multi-rotation magnetic head 3 is compared at the positions of the first edit gap and the second edit gap, and the Select and output the output signal.

However, the time timings of the first edit gap and the second edit gap are controlled by the timing of the synchronization signal detected by the synchronization detection 23.

Next, the equalizer 22 corrects the frequency characteristics of the signal output from the signal selection 21, and the synchronization detection 23
Output to.

As described above, the synchronization detection 23 decodes the digital signal, detects the synchronization reference from the synchronization pattern and ID data, and outputs it to the signal selection 21 and subsequent block.

As described above, if the main block configuration shown in FIG. 4 is implemented, the opportunities for signal selection will be reduced compared to the embodiment shown in FIG. Since processing can be performed in the signal domain, the circuit scale can be reduced.

[0051] Furthermore, the problem of reduced opportunities for signal selection is not so much of a problem if it is taken into consideration that the characteristics of track bending almost exhibit first-order characteristics. The apparent head width MTw of the rotating magnetic head is not affected by adjacent crosstalk.
This allows the tracking margin to be expanded.

Next, FIG. 6 shows a block diagram of a main part of a magnetic recording/reproducing apparatus according to an embodiment of the invention according to claims 1 and 4.

[0053] Magnetic tape 1, multi-rotation magnetic head 2,
3 is the same as the arrangement described above (FIG. 2), and the main signal recorded on the magnetic tape 1 is a digital signal.

In addition, as shown in FIG. 6, the magnetic tape 1, multi-rotation magnetic heads 2, 3, pilot amplitude detection 11,
12. The configuration of the power difference is the same as the configuration in (FIG. 1).

Next, the delay 31 delays the reproduction signal output from the multi-rotary magnetic head 2 and corrects the time axes of the multi-rotary magnetic heads 2 and 3 to make them the same time axes.

Next, in the signal addition 32, the output of the delay 31 and the output of the multi-rotation magnetic head 3, which have the same time axis, are added and output.

Next, in the equalizer 33, the signal addition 32
Corrects the frequency characteristics of the signal output from the synchronization detection 3
Output to 4.

The synchronization detection 34 decodes the digital signal, detects the synchronization reference from the synchronization pattern and ID data, and
Output to subsequent block.

[0059] Here, the characteristics of the configuration shown in (Fig. 6) are as follows.
The signal addition 32 adds the output of the delay 31 whose time axis has been corrected and the output of the multi-rotation magnetic head 3.

[0060] Therefore, the signal reproduced from the main track is doubled by addition, and the signal reproduced from the adjacent track is a component reproduced from separate tracks due to the arrangement of the multi-rotary magnetic heads 2 and 3. Since it is an addition, the route is doubled and the signal SN is improved.

Furthermore, by adding the random noise generated during the reproduction process of the multi-rotation magnetic heads 2 and 3 as described above, the root value is doubled, so that the signal SN is further improved.

Finally, in this embodiment shown in FIGS. 1, 4, and 6, the case where there are two multi-rotation magnetic heads has been explained, but the number of multi-rotation magnetic heads is N. Similar results can be obtained by increasing the number of times (N is an integer of 3 or more), and further improvement can be achieved.

Furthermore, in this embodiment, tracking error detection using the tracking error detection pilot reproduced as adjacent crosstalk has been described, but the tracking error detected from the main track (track 2) shown in FIG. Tracking errors can also be detected by comparing the output levels of the pilot f2.

In this case, since it is not affected by pilot level fluctuation errors during recording, it becomes a meaningful configuration.

[0065]

As described above, according to the present invention, tracking error detection pilots reproduced as adjacent crosstalk from each of the multi-rotary magnetic heads are compared using the head arrangement of the rotary magnetic heads to perform tracking. Since errors are detected, the detection area can be expanded.

Furthermore, if the tracking error is detected by adding the time-base corrected output signals, the detection sensitivity can be improved.

[0067] Furthermore, if the reproduction output is selected based on the number of errors for each synchronization block, adjacent crosstalk,
Additionally, the apparent head width can be increased without being affected by adjacent crosstalk, and tracking margin can be expanded.

Furthermore, since switching can be performed in the analog domain, the circuit can be simplified.

Furthermore, since the time-base corrected signals are added, the signal SN can be improved.

In particular, since the head arrangement is used, adjacent crosstalk signals can also be improved, which is an extremely significant invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus of the present invention.

FIG. 2 is an arrangement diagram showing the arrangement of a rotating magnetic head of the present invention and a pilot for tracking error detection.

FIG. 3 is a recording format diagram showing an example of the recording format of the digital signal in FIG. 1;

FIG. 4 is a block diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention.

FIG. 5 is a recording format diagram showing an example of the recording format of the digital signal in FIG. 4;

FIG. 6 is a block diagram showing an embodiment of the magnetic recording/reproducing device of the present invention.

FIG. 7 is a diagram showing input positions for detecting tracking errors in FIG. 1;

[Explanation of symbols]

1 Magnetic tape 2 Multi-rotation magnetic head 3 Multi-rotation magnetic head 4 Equalizer 5 Equalizer 6 Synchronization detection 7. Synchronization detection 8 Error number detection 9 Error number detection 10 Channel selection 11 Pilot amplitude detection 12 Pilot amplitude detection 13 Power difference 20 Delay 21 Signal selection 22 Equalizer 23 Synchronization detection 31 Delay 32 Signal addition 33 Equalizer 34 Synchronization detection 41 Delay 42 Addition

Claims (4)

[Claims] 1. A magnetic recording and reproducing device that records and reproduces a pilot for tracking error detection along with a main signal on diagonal tracks on a magnetic tape using a rotating magnetic head, which has the same azimuth angle and the same recording signal track. Two multi-rotating magnetic heads that overlap and play,
The present invention is characterized by comprising two pilot amplitude detections for detecting amplitudes of the pilots from the two multi-rotation magnetic heads, and a power difference for detecting a tracking error by taking a difference between the two pilot amplitude detection outputs. Magnetic recording and reproducing device. 2. A magnetic recording and reproducing device in which the main signal recorded on the magnetic tape is a digital signal whose minimum unit is one synchronization block consisting of a synchronization pattern, ID data, data, and an error correction code, The main signal is reproduced by two multi-rotation magnetic heads having the same azimuth angle and reproducing the same recorded signal track in an overlapping manner, and two equalizers, two synchronization detections, and two error number detections are used to reproduce the two The main signal reproduced from one multi-magnetic head is digitally decoded, and the two decoded signals are
2. The magnetic recording and reproducing apparatus according to claim 1, further comprising selecting a channel with a smaller number of errors for each synchronous block in which the D data match and outputting the selected one. 3. The main signal recorded on the magnetic tape is a magnetic recording/reproducing device configured to include at least m (m is an integer of 1 or more) free signal areas (hereinafter referred to as edit gaps). two multi-rotary magnetic heads having the same azimuth angle and reproducing the same recording signal track in an overlapping manner; and a delay for aligning the time axes of reproduction signal outputs of the two rotary magnetic heads; A signal selection device is provided which switches and outputs a signal for each edit gap period so as to compare two playback signal output levels at m points between the edit gaps and select the one with the highest playback signal output level. The magnetic recording and reproducing apparatus according to claim 1, characterized in that: 4. A main signal recorded on a magnetic tape is reproduced by two multi-rotation magnetic heads having the same azimuth angle and reproducing the same recorded signal track in an overlapping manner, and the two reproduced 2. The magnetic recording and reproducing apparatus according to claim 1, comprising a delay for aligning the time axes of the signals, and a signal addition for adding the two reproduced signals whose time axes have been corrected.