KR0130179Y1 - Curcuit for detecting record signal in recording/reproducing system - Google Patents

Abstract

The present invention relates to a recording signal discrimination circuit of a recording and reproducing apparatus. In the related art, a recording signal cannot be distinguished from a V-type applied by a digital method or an analog method. Or, the user had to check and play the tapes manually.

In view of this point, the present invention detects polarized light by scanning light onto a recording pattern when performing a reproducing operation, and determines whether it is a digital signal or an analog signal, and automatically selects a corresponding reproducing mode according to this determination. The tape can be played back to satisfy the user.

Description

Recording signal discrimination circuit of recording and reproducing apparatus

1 is a block diagram of a conventional V-Cal.

2 is a block diagram of a recording signal discrimination circuit of the present invention.

3 is an exemplary view showing a recording pattern of a tape.

4 is an exemplary view showing the azimuth angle of the head,

5 is an explanatory diagram showing light detection.

* Explanation of symbols for main parts of the drawings

1: Head Drum 2: Video Head

3: light generating unit 4: lens system

5 polarization detection unit 6 photoelectric device

7: amplifier 8: digital signal processor

9: analog signal processing unit 10: system control unit

11: video / audio signal processor 12: audio head

13: phase detection head 14: control head

15 capstan motor 16 drum motor

17: motor drive unit 18: servo system

19: Pinch Roller 20: Capstan

SW ₁ : switch

The present invention relates to the determination of recording signals of a recording / reproducing apparatus. In particular, analog signals and digital signals, which are NTSCs recorded at different azimuth angles by detecting an azimuth angle according to a recording signal of a tape, are described. The present invention relates to a recording signal discrimination circuit of a recording and reproducing apparatus which performs a reproducing operation of a corresponding mode.

FIG. 1 is a configuration diagram of a conventional V-Cal, and as shown therein, a head drum 1 mounted with a video head 2 and driven by a drum motor 16 is conveyed by driving a capstan motor 15. An audio head 13 for detecting an audio signal from a tape, a control head 14 for detecting a control signal, a phase detection head 13 for detecting a phase according to the rotation of the drum 1, and the control Servo system 1 for controlling the drum motor 16 and the capstan motor 15 by controlling the motor driving unit 17 by receiving the outputs of the head 14 and the phase detecting head 13, and the operation of the system. It consists of a system control unit 10 for controlling the, reference numerals 19 and 20 of the figure is a pinch roller (Pinch Roller) and capstan (Capstan) for transferring the tape.

The video head 2 is formed with an azimuth angle to prevent signal leakage between adjacent tracks recorded on the magnetic surface of the tape.

That is, when the diameter of the drum is 62 mm in the VHS method, the rotation speed of the head drum 1 is 1800 rpm, and the running speed of the tape is 33.35 mm, and a constant pattern is formed on the magnetic surface of the tape by the video head 2. The track pitch of the formed recorded signal is 58 um, and the azimuth angle for preventing signal mutual leakage between the head 2 and the adjacent tracks is normalized to ± 6 °.

Referring to the operation of the conventional circuit as follows.

When the video tape is inserted into the V-Cal and a play command is input, the tape mounted on the head drum 1 from the outside is transferred from the supply side reel to the mounting side reel at a constant speed as the capstan motor 15 is driven. 1) Drive the surface and various guide posts. At this time, the servo system 18 receiving the rotation signal from the phase detection head 13 attached to one end of the drum motor 16 controls the motor driving unit 17 so that the head drum 1 rotates at a constant speed. Further, when the control head 14 detects a control signal from the track below the tape formed in the tape running direction, the servo system 18 controls the capstan motor 15 for running the tape at a constant speed.

Then, the video head 2 mounted on the head drum 1 rotated by the drum motor 16 detects an image signal recorded on the magnetic surface of the tape, outputs it to the video / audio signal processor 11, and fixes the fixed head. The audio head 13 detects the audio signal recorded on the tape magnetic surface and outputs the audio signal to the video / audio signal processor 11.

Therefore, the video / audio signal processor 11 receiving the detection signals of the video head 2 and the audio head 13 reproduces the video and audio through a demodulation process.

However, a general recording and reproducing apparatus in which only a digital signal is recorded or reproduced or a digital / analog recording / reproducing method is not able to discriminate a recorded signal by noise or the like even when there is no circuit or a detection circuit for detecting a tape recording format. Cases may occur. Therefore, in case of malfunction due to noise, the user may make a mistake due to a malfunction of the device, and there is an inconvenience in that the user must select the analog or digital playback mode by checking the tape every time.

In order to solve this problem, the present invention scans light onto a video tape and detects a polarization rate according to a recorded signal to determine a recording signal. The invention is described in detail with reference to the accompanying drawings as follows.

In general, in order to record and reproduce a digital video signal having a data processing speed of several tens of Mbps, the frequency band allocated to each head is higher than that of an analog signal such as NTSC. For example, to record and reproduce 300Mbps using two heads, the maximum frequency per head is 15MHz, which is about three times higher than the maximum frequency of 4.4MHz handled by the conventional VHS method. Therefore, in order to realize recording and reproduction of a high density digital signal, it is necessary to increase the rotational speed of the drum or to simultaneously perform recording and reproduction with a plurality of heads.

At this time, the track pitch is reduced by an integral multiple of the conventional rotational speed in terms of the drum rotational speed and the track pitch is inversely reduced by the number of rotational heads additionally attached in the number of heads. Accordingly, when the track pitch of the recording signal is narrowed, it is necessary to increase the azimuth angle of the head than the conventional method by increasing the signal mutual interference effect between adjacent tracks.

The present invention adopts the existing helical driving method and controls the mode according to the user's request and the discrimination of the recording signal to select the digital recording and analog recording and playback. The head corresponding to the digital signal band is simultaneously mounted and the rotational speed of the head drum is adjusted according to the recording or playback mode. That is, during recording, the digital or analog recording function is determined according to the user's selection, and during playback, the mode is automatically selected according to the discrimination of the signal recorded on the tape to enable the reproduction of the digital or analog signal.

2 is a block diagram of a recording signal discrimination circuit of the recording and reproducing apparatus of the present invention, as shown therein, which scans light through the lens system 4 to any part of the magnetic surface of the tape which is mounted on the head drum 1 and is running. The light generating unit 3, the polarization detecting unit 5 for detecting the polarized light as the light of the light generating unit 3 is reflected and polarized by the tape, and the output of the polarization detecting unit 5 A photoelectric element 6 for converting into a signal, an amplifier 7 for amplifying the output of the photoelectric element 6 and outputting it as a switching signal, and mounted on the head drum 1 in accordance with the output of the amplifier 7 Consisting of a switch SW ₁ for switching the detected signal of the video head 2 to the digital signal processor 8 or the analog signal processor 9, wherein the light generated from the light generator 3 is magnetized. When the light is scanned on the surface of the material and reflected with linearly polarized light, the plane of polarization immediately before incidence Handed down the elliptically polarized light there is generated a large rotational angle (Kerr) as the rotation angle and the rotation angle of the polarization plane (direction of the major axis of the elliptically polarized light) is incident relative to the magnetization component in the surface. That is, the degree of rotation of the polarization plane reflected from the magnetic plane of the tape recorded at ± 6 ° and the polarization plane reflected from the magnetic plane of the tape recorded at ± 15 ° is different.

As shown in FIG. 4, the head drum 1 is equipped with four analog heads having an arbitrary azimuth angle and four digital heads at arbitrary angular intervals. It is configured to have a winding angle, and the relative speed of the head drum 1 is 3600rpm (tape running speed 11.6m / s in case of 62mm diameter drum) in response to the recording wavelength of the video signal of about 15MHz band or more during digital recording and reproducing. Relative speed of the head drum 1 is rotated at a speed of 1800 rpm (speed of tape travel of 5.8 m / s in the case of a 62 mm diameter drum) corresponding to the recording wavelength of the video signal in the band of about 5-7 MHz.

The analog head mounted on the head drum 1 has a counter angle of 180 ° and has an azimuth angle of ± 6 ° to record and reproduce a signal recorded by the conventional VHS method, and the digital head is 180 degrees. As a head having an opposing angle of degrees, it has a phase angle at an arbitrary angle with an analog head, and has an azimuth angle larger than ± 6 degrees to record and reproduce digital signals such as high-definition television (HDTV).

The operation and effects of the recording signal discrimination circuit of the present invention recording and reproducing apparatus will be described in detail with reference to FIGS. 3 to 5 as follows.

When the video tape is inserted into the V-Cal and a play command is input, the tape mounted on the head drum 1 from the outside is transferred from the supply side reel to the mounting side reel at a constant speed as the capstan motor 15 is driven. 1) Drive the surface and various guide posts. At this time, the servo system 18 receiving the rotation signal from the phase detection head 13 attached to one end of the drum motor 16 controls the motor driving unit 17 so that the head drum 1 rotates at a constant speed. Further, when the control head 14 detects a control signal from the track below the tape formed in the tape running direction, the servo system 18 controls the capstan motor 15 for running the tape at a constant speed.

Then, the light of the light generating unit 3 is collected by the lens system 4 and the collected light is scanned at one end of the tape mounted on the head drum 1, thereby polarizing and refraction by the azimuth angle of the signal recorded on the tape. It is done. At this time, when the light generated from the light generating unit 3 is reflected on the surface of the magnetized tape and reflected by linearly polarized light, the incident linearly polarized plane is rotated to generate an elliptically polarized light. Proportional.

That is, when the signal recorded according to the mode is described with reference to the pattern shown in FIG. 3, FIG. 3 (a) is a track pattern of an analog signal and is compatible with the tape pattern of the conventional VHS standard. An inclined track has a track pitch (T _P '= 2T _P ) of a certain interval and a video signal with an azimuth angle of ± 6 ° is recorded. An audio signal is recorded at the top of the track and a control signal is recorded at the bottom of the track. do. In addition, FIG. 3 (b) shows a track pitch T _P having a predetermined interval as a track pattern of a digital signal, and an inclined track is formed so that a control signal is recorded at the bottom of the track and an audio signal is recorded at the top of the track.

Therefore, the degree of rotation of the polarization plane reflected at the magnetic plane of the tape recorded at ± 6 ° and the polarization plane reflected at the magnetic plane of the tape recorded at ± 15 ° is different.

At this time, the light reflected from the tape is received by the polarization detection unit 5 is converted into an electrical signal in the photoelectric element (6) and the electrical signal is amplified by a predetermined level in the amplifier (7) to the switch SW ₁ as a switching signal Is output.

That is, if the polarization detector 5 is divided into upper and lower portions as shown in FIG. 5 to detect only the refraction signal of the tape on which the digital signal is recorded, the digital signal is recorded on the video tape and the polarization detector 5 refracts. When the signal is detected, the switch SW1 receiving the switching signal of the amplifier 7 amplifying the electrical signal of the photoelectric element 6 connects the video head 2 to the digital signal processor 8.

Accordingly, the capstan motor 15 rotates the capstan at 1/2 the speed of the analog mode according to the drive signal of the motor driving unit 17 to convey the tape, and the drum motor 16 moves the head drum ( As 1) is rotated at 3600 rpm and the digital head of the video head 2 is repeatedly switched, the digital signal processor 8 receives and demodulates the digital detection signal of the head 2 to reproduce a high density digital image.

On the other hand, when the analog signal is recorded on the video tape and the polarization detector 5 does not detect the refraction signal and the output of the amplifier 7 is disabled, the switch SW1 switches the video head 2 to the analog signal processor 9. ).

Accordingly, the capstan motor 15 rotates the capstan at a constant speed Vt to feed the tape by the control signal of the motor driving unit 17, and the drum motor 16 moves the head drum 1. Rotate at 1800rpm and repeatedly switch the analog head of the video head 2, and the analog signal processor 9 receives the output of the head 2 to demodulate to reproduce the image of the NTSC.

On the other hand, when the analog signal and the digital signal are recorded on the tape as a teaching material, the output of the amplifier 7 is switched as the polarization detector 5 detects the refraction signal during the tape reproducing operation. 2) is connected to the corresponding signal processor to reproduce the recorded signal.

As described in detail above, the present invention detects a video signal for one track to determine whether it is an analog signal or a digital signal, and automatically plays back the corresponding mode according to the determination. In addition to retaining the functionality of digital V-Cal, the existing analog system can be used to improve product quality. In particular, even when the analog signal and the digital signal are mixed and recorded alternately, the tape can be reproduced by one operation, thereby providing a satisfactory effect to the user.

Claims (1)

A lens system 4 for condensing and scanning the light of the light generating unit 3 on any part of the tape magnetic surface running on the head drum 1, and the light collected by the lens system 4 is reflected from the tape. And polarized light, the polarization detection unit 5 for detecting the polarized light, the photoelectric element 6 for converting the output of the polarization detection unit 5 into an electrical signal, and the output of the photoelectric element 6 The digital signal processor 8 or the analog signal processor 9 outputs a detection signal of the amplifier 7 outputting the switching signal and the video head 2 mounted on the head drum 1 in accordance with the output of the amplifier 7. A recording signal discrimination circuit of a recording / reproducing apparatus, characterized by comprising a switch (SW1) for switching to a loop to form a reproducing loop.