JPS59188875A - Video recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the accurate and stable tracking by extracting the center frequency components different from each other for crosstalk component out of adjacent recording tracks which is contained in the FM wave reproduced from the record track and obtaining the tracking information. CONSTITUTION:When a head switch pulse is set at level ''1'', a video track is formed by a head 10. In this case, the center frequency of the FM wave is set at fo. While the video track is formed by a head 11 when said switch pulse is set at level ''0''. In this case, the center frequency of the FM wave is set to be fa or fb. Thus the center frequency has a difference by (10/2)fH between adjacent tracks. When the head 10 is set under an optimum tracking state, the FM wave having center frequency fo which s recorded on a track 43 is reproduced. At the same time, the crosstalk components given from the adjacent tracks 42 and 44 are also reproduced. In other words, the crosstalk components of center frequencies fa and fb are obtained from tracks 42 and 44 respectively. The levels of these crosstalk components are compared with each other to obtain the tracking information.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an image recording and reproducing apparatus which forms a recording trunk without creating a guard band and performs recording and reproduction of signals by means such as azimuth recording. In particular, we will focus on improving tracking information detection means.

[Technical background of the invention]

As a conventional tracking information detection means in this type of image recording/reproduction system, pilot signals for detecting tracking information of four types are multiplexed with the video signal and recorded, and during playback, the tracking information is detected between trunks that match each other. There is a method in which tracking information is obtained from the magnitude of the mutual beat frequency of generated pilot signals.

[One point between background technology]

However, the above method requires a pilot signal generation circuit and has the disadvantage that the circuit configuration is complicated.

Furthermore, since the pilot signal is superimposed on the FIJ wave that has been converted to FM by the video signal, there is a risk that the pilot signal may leak into the reproduced video signal and deteriorate the image quality. For this reason, the superimposition level of the pilot signal is not set very high, and as a result, the S/N ratio of the externally generated pilot signal becomes insufficient, making it difficult to perform accurate and stable tracking.

[Purpose of the invention]

An object of the present invention is to provide an image recording and reproducing apparatus that is free from the risk of image quality deterioration, can perform accurate and stable tracking, and can be manufactured with a simple configuration and at low cost.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides an F recording trunk having a predetermined center frequency in a first recording trunk formed every other trunk.
The H7 wave is recorded, and the F and M waves having different center frequencies from the center frequency are recorded on a second recording trunk formed in opposition to the first recording track. Then, during playback, the rough center frequency component of the crosstalk components from the second recording trunks on both sides rich in FM waves reproduced from the first recording trunk is extracted, and the magnitudes of the two are compared. The feature is that tracking information can be obtained by

[Embodiments of the invention]

FIG. 1 is a block diagram showing the configuration of a recording system according to an embodiment of the present invention.

In FIG. 1, the video signal input terminal 1 is
The signal is supplied to a Flvi' modulator 3 via a mixer 2. F at the output of the FIJ modulator 3, that is, the video signal
After the M-modulated FM wave is current amplified by the recording amplifier 4, the recording/reproduction changeover switch 5.6 records 1NII.
It is supplied to the rotary transformer 7.8 via 5a and 6a. The outputs of the lithoofons 7 and 8 in the rotor are respectively supplied to recording and reproducing heads 10 and 11 which are fixed at 180 DEG different positions on the rotating drum 9. The rotating drum 9 is fixed to the shaft of a DC motor 12, and is rotated at 30 rps by the stiff motor 12.
Rotated and driven by. Thus head 10. 11, video signals of one trunk and one field are recorded on the magnetic tape 13 that is driven to run along the circumferential surface of the rotating drum.

A rotating plate I4 is attached to the shaft of the motor 12. There are magnets (magnets) at 180° different positions on this rotary plate 14.
, '16 is installed. Reference numeral 17°4.8 denotes a rotation detection sensor that transmits a signal by persevering with the magnetism of the magnets 15 and 16, and is installed oppositely around the rotating plate I4 at 180° different positions. In this way, each rotation detection sensor 17, 18 sends out one pulse signal each time the rotary tom 9 rotates once. These pulse signals are input to the head switch pulse generator 19. The head switch pulse generator 19 generates a head switch pulse consisting of a 30 Hz square wave according to the input pulse signal.

This head switch pulse causes the head 1o to switch to the magnetic tape 1.
During the period when the head 11 is in sliding contact with the
During the period in which the magnetic tape is in sliding contact with the magnetic tape 13, it is at the "0" level. Such a head switch pulse is applied to the flip-flop circuit 2°. flip frog circuit 2o
The pulse whose frequency is divided into two by
After the polarity is inverted by 1, the signal is applied to a 1-shot multivibrator 22, and on the other hand, it is applied directly to another 1-shot multivibrator 23. Both the one-shot multivibrators 22 and 23 are triggered by the negative edge of the input pulse. As a result, one vibrator 22 is triggered by the positive edge of the output pulse of the flip-flop circuit 2o, and the other vibrator 23 is triggered by the negative edge of the output pulse of the flip-flop circuit 2o.

SA in FIG. 2 is the output pulse waveform of the head switch pulse generator 19, SB [output pulse wave of the flip-flop circuit 20 + ft, sc 1-shot multivibrator 2
The output pulse waveform of No. 2, SD is the output pulse waveform of the one-shot multivibrator 23.

In FIG. 1, a one-shot multivibrator 22.
Each of the output pulses 23 is applied to each gate of an analog gate FET 26, 27 via a resistor 24, 25, respectively. The FETs 26 and 27 are turned on when the gate input is at the "1" level, and turned off when the gate input is at the "0" level. 1 on the source side of each of the FETs 26 and 27, source 28.
Karasu, Ta + Ea obtained by adjusting vehicle pressure + of 29 and -'E with volume 30.31.

−gb is given. Further, the voltage appearing on the drain side of each FET 26 and 27 is commonly applied to the other input terminal of the mixer 2.

In this embodiment, the signal 1 applied to one input terminal of the mixer 2 is
The average direct current vehicle pressure of the signal is set to O, V. Therefore, +Ea and - given from FET26.27
Eb gives an offset in the positive and negative directions to the video signal centered at 0■.

sg shown in FIG. 2 shows how the above offset is given. In the period Ukj of T1, F
Since ET' 26 is ON, +E during this period T1.
It is offset by a.

During the period T2, FET27 is ON, so
During this period T2, it is offset by -gb. In this way, the mixer 2 sends out a video signal whose average voltage changes in the following order for each field period as shown in FIG. 2 SE: O→+Ea→O→−El)→0... .

As a result of inputting the video signal 4H whose average voltage has changed in this way to the 2M modulator 3, the FM signal which is the output of the Flvf modulator 3
The center frequency of the wave also changes in response to the change in the average vehicle pressure. In this example, F when the average voltage is OV
With respect to the center frequency fo of the M wave, in the period T1 in FIG. 2, the center frequency fH (J'H is the frequency of the horizontal synchronization signal) is as high as f a = , f c) + ! -! l! -j'H, and in period T2 in FIG. 2, the center frequency is set so that fb=fo-"fH, which is lower by "fH". Therefore F) J modulator 3
The center frequency of the Fh/f wave output from is fO-* fa-+ J' o →f1) → for each field period.
The result will be something like f □.

The reason why fa and fb were selected to be 2 and fa is that the crosstalk frequency generated between matching trunks is imprinted on the luminance signal of the video signal to form an interleave frequency. Therefore, it is not necessarily necessary to set it to 10 fH.

FIG. 3 shows a pattern of video trunks recorded and formed obliquely on the magnetic tape 13 by the above-mentioned recording means.

In Figure 3, 41°43.45...Hahe, Rad 10
42, 44, 46, . . . are video trunks as second recording tracks formed by the head 11. In this example, the head switch pulse is "l".
When the head switch pulse is at the "0" level, a video track is formed by the head 1o, and the center frequency of the FM wave at that time is J"0", and when the head switch pulse is at the "0" level, a video trunk is formed by the head 1o. and then F
The center frequency of the lvi wave is set to be fa or fb. Therefore, the trunk 41°42
．． The central station of the FM waves recorded at 43.44...? The inverse numbers are fo, fa, j'o, fb... Cumashi I
Between trunks that compete with each other, the center frequencies are true across -J'H.

FIG. 4 is a block diagram showing the configuration of a v+r+ production system according to an embodiment of the present invention.

In FIG. 4, the reproduction signal sent from the heads Jθ, 11 via the reproduction side 5b, 6b of the recorder/older recorder switch 5°6 is input to the switcher 51. Switcher 5
1 is supplied with a head switch pulse from the head switch pulse generator 19 described above.
During the period when 0 is in sliding contact with the magnetic tape I3, the head 1 is turned off and input via the playback ffl+q5b of the moxibustion switch 5.
During the period when the head 11 is sucking the magnetic tape 13, the playback signal from the changeover switch 6 is set to the full playback signal.
l 6 b 'f: allows the reproduction signal from the human-powered head J1 to pass through. As a result, the Nuisoture 51 outputs continuous reproduced FM waves. This reproduction FVL
The signal is demodulated by the Fh/[1 summer modulator 52, and a reproduced image signal is sent from the output terminal 53.

On the other hand, after one regeneration ff1115b of the changeover switch 5,
A reproduction signal from the head 10 appearing every other field is supplied to an analog gel 54. A horizontal synchronizing signal separated and extracted from the output of the yMH sweeper 52 by a horizontal synchronizing signal separator 55 is applied to this analog gate 54 as a gate signal. The signal passing through analog gate 54 is supplied to BPF 56.57. BPF56 has a band that passes the center frequency fa, and BPF57
has a band that passes the center frequency fb. B.P.
The signal passing through F56.57 is sent to envelope detector 5B.
, 59, and the detected outputs are supplied to sampling and hold circuits 60 and 61, respectively.

The horizontal synchronizing signal separated and extracted by the horizontal synchronizing signal separator 55 is applied to the sampling and holding circuit r66θ, 61 as a sampling pulse. Therefore, the outputs of the envelope detectors 58 and 59 are sampled and held every time the horizontal synchronizing signal arrives.

SF in FIG. 5 is the output waveform of the switcher 51, and S
G is the output C skin 71 cedar of the horizontal synchronization signal separator 55,
SH is the output waveform of the analog gate 54. Above SH
As shown in FIG. 2, only the portion of the reproduced signal from the head 10 that is in phase with each horizontal synchronization signal is gated. sr.
and SJ are the output waveforms of the envelope tester 56 and 57, and J, sK and SL are the sampling and hold circuit 5.
This is an example of an output waveform of 0.61.

The explanation returns to FIG. 4. Sampling hold circuit 60.
The output signal 7ri7 of 61 becomes the differential input of the dynamic amplifier 62. The output of the differential amplifier 62 becomes tracking information.

That is, as mentioned above, the BPF 56 detects only fa, and the BPF 57 detects only rifb.As a result, during optimal tracking, both differential inputs are equal and the output of the differential amplifier 62 becomes 0. When a tracking deviation occurs, a difference occurs in the differential input, and the output of the differential amplifier 62 becomes a positive voltage output or a negative voltage output with a polarity and magnitude depending on the direction and amount of the tracking deviation. The output of dynamic amplifier 62 is tracking information and is sent out from terminal 63.

Figure 6 shows the video track and the throat 1θ.

11 is a diagram showing the relationship with No. 11. Similarly to when recording, throat 10 is on tracks 41, 4, ? , 45...The servo is applied to trace the center of each trunk every other trunk. IOC is head 10 for track 43
is the optimal tracking state, and 10
10a shows a case where a trunking deviation occurs in a direction delayed with respect to the tape running direction, and 10b shows a case where a trunking deviation occurs in a direction advanced with respect to the tape running direction. When the head 10 is at position 10c, that is, in the optimal tracking state, the trunk 4
The center frequency fOOFM wave recorded in No. 3 is reproduced, but at this time, crosstalk components from adjacent tracks 42 and 44 on both sides are also reproduced. i.e. trunk 4
There is crosstalk at the center frequency fa from the trunk 44, and there is crosstalk at the center frequency fb from the trunk 44. During optimal tracking, the magnitudes of the crosstalk components fa and fb are fa=fb. 10 more
In the case of a, /'a>fb, and in the case of 10b, fa<fb.

In the case of this embodiment, since the heads 10 and II have different azimuth angles, the amount of crosstalk is relatively small, but crosstalk is comparatively large in the horizontal synchronization signal section where the modulation frequency is low. Therefore, in this embodiment, fa and fb are used for the same phase portion as the horizontal synchronizing signal as described above.
is being detected.

The present invention is not limited to the one embodiment described above.

For example, in the embodiment described above, a magnetic tape is used as the recording medium, but a magnetic disk or the like may also be used.

In the above embodiment, the center frequency fo of the FM wave recorded on the first recording trunk formed every other track is recorded on the second recording trunks on both sides adjacent to the first recording track. The central same wave numbers fa and fb of the FM waves to be
We have shown the case where one is set high and the other is low, but fo
Both ja and Jb may be set high, or conversely, both may be set low. In short, J'a against Joo,
It is only necessary that J'b be set to different round numbers. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, with respect to the center frequency of the FM wave recorded on the first recording trunk formed every other
The center frequency of the FM wave recorded on the second recording trunk formed between the recording trunks is made to be true at the intersection U, and the center frequency of the FM wave recorded on the second recording trunk formed between the recording trunks of By extracting four different center frequency components of the blacktalk components from the second pitching trunks on both sides of the pitcher and comparing their sizes to obtain tracking information, it is possible to There is no risk of image quality deterioration due to setting the pilot signal to M blue, and accurate and stable tracking can be performed, and there is no need to worry about mechanically vibrating the head to obtain tracking 11N as in the wobbling method. Easy to configure and low cost! can provide an image recording and reproducing device.

[Brief explanation of the drawing]

1 to 6 are diagrams showing an example of an actual image of the present invention. FIG. 1 is a block diagram showing the configuration of the recording system, FIG. 2 is a signal waveform diagram of each part for explaining the operation of the recording system, and FIG. The figure shows the pattern of recording tracks recorded and formed on the magnetic Daeg, Figure 4 is a block diagram showing the configuration of the reproduction system, Figure 5 is a signal waveform diagram of each part to explain the operation of the reproduction yarn, and Figure 6 is FIG. 3 is a diagram showing the relationship between the head and the trunk during tracking. 1...Video signal input terminal, 2...Mixer, 5.6.
...Recording/reproduction switch, 7, 8...Rotary transformer, 9...Rotating drum, 10.11...Notation playback head, 13...Magnetic tape, 12...DC motor, 14...・Rotating plate, 15.16...Magnet, 1
7.18... Rotation detection sensor. Applicant's representative Patent attorney Takehiko Suzue-42 Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Case Indication Special@Japanese 58-63324 No. 3, Person making the amendment Relationship to the case Patent applicant (037) Olinos Optical Industry Co., Ltd. Taisha 4, Agent

Claims (1)

[Claims] Recording FM waves modulated by video signals. Signals are recorded and played back by forming recording trunks on three media in one field or one frame period without creating a guard band between adjacent trunks. In the image recording and reproducing apparatus, the apparatus comprises means for recording an FM wave having a predetermined center frequency on first recording tracks formed every other time, and a second recording track formed between the first recording tracks. means for recording FM waves having different center frequencies from the center frequency on a trunk; and FM waves recorded on the first recording trunk and the second recording trunk.
means for reproducing the IJ wave to obtain a reproduced video signal;
Means for extracting different center frequency components of crosstalk components from adjacent second recording tracks included in FM waves reproduced from a recording trunk of V# is equipped with a means to compare the
An image recording and reproducing device with a special feature.