KR0179133B1 - Digital recording and reproducting apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording and reproducing apparatus which accurately detects the same track by reading a predetermined number of times by reproducing a drum speed at a predetermined speed when reproducing a track recorded at 1x speed. The capstan motor rotates the drum at 1x speed or Nx speed while rotating at the same speed, repeats the same track N times, and selects and outputs the best data among them, thereby accurately detecting the data and increasing the reliability of the data. Favorable to the track.

Description

Digital recorder

1 is a recording block diagram of a conventional digital recording / reproducing apparatus.

2 is an operation waveform diagram of each part of the signal proxy of the conventional recording and reproducing apparatus.

FIG. 3 is a tracking state diagram shown on the tape during recording according to FIG. 1. FIG.

4 is a reproduction block diagram of a conventional digital recording / reproducing apparatus.

5 is an operation waveform diagram of each unit during signal reproduction of a conventional recording and reproducing apparatus.

6 is a tracking state diagram during signal reproduction when there is no change in environmental temperature in correspondence with conventional signal recording.

7 is a tracking state diagram during signal reproduction when there is a change in environmental temperature in correspondence with conventional signal recording.

FIG. 8 is a state diagram in which tracks are deformed as the tape sags during playback according to FIG.

9 is a reproduction block diagram of a digital recording / reproducing apparatus according to the present invention.

10A is a tracking state diagram when reproducing a signal when there is no change in environmental temperature in response to signal recording according to the present invention.

10B is a tracking state diagram during signal reproduction when there is a change in environmental temperature in correspondence with signal recording in accordance with the present invention.

* Explanation of symbols for main parts of the drawings

101: tape 92: playback amplifier

92: demodulation section 94: error correction

95: data selector 96: formatter

97: Oscillator 98: Playback mode selector

99: divider SW1: switching unit

99-1: control signal detection unit 99-2: capstan control unit

99-3: Capstan motor drive unit 99-4: Drum speed control unit

99-5: Drum Motor Drive

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording and reproducing apparatus, and more particularly, to a digital recording and reproducing apparatus for accurately detecting data by reading the same track a predetermined number of times by increasing the drum speed at a predetermined double speed than when recording the tape. will be.

1 is a block diagram of a conventional digital recording / reproducing apparatus, in which a formatter (11) for converting digital data into a form suitable for recording on a tape, and an error correction code is added to data converted by the formatter (11). The error correcting unit 12 for correcting, the demodulation unit 13 for demodulating the data for which the error is corrected by the error correction unit 12, and the data demodulated in the demodulation unit 13 are amplified and the head disposed on the rotating drum. The recording amplifier 14 for recording on the tape via the control signal, the control signal generator 16 for recording the control signal as a reference for video and head rotation to the control track of the tape through the control head, the formatter 11, and the error. Correction unit 912, oscillation unit 17 for providing a clock to the modulation / demodulation unit 13, and controlling the rotation speed of the capstan motor at the time of recording so that the running speed of the tape is constant, The capstan controller 18 controls the signal to be recorded at a precise pitch, the capstan motor driver 19 for driving the capstan motor 200 under the control of the capstan controller 18, and the rotation phase of the drum motor 23 during recording. Drum control unit 21, which controls to rotate in synchronization with the phase of the normal video signal recorded at all times so that the vertical synchronization signal in the video signal is recorded at a predetermined position on the tape, the drum according to the control of the drum control unit 21 It consists of a drum motor drive unit 22 for driving the motor 23.

Here, frequency generation detected by the capstan motor 20 (Frequency Generator); FG) signal is fed back to the capstan control unit 18 to detect the rotational speed and phase of the tape, and the FG signal and phase generator detected by the drum motor 23; PG is fed back to the drum controller 21 to detect the rotational speed and phase of the drum.

The digital data inputted in the above-described first degree is converted into a format suitable for recording on a tape in the formatter 11, and then the error correction code 12 adds an error correction code to the converted data to correct the error.

The error-corrected data is modulated and demodulated by the modulation / demodulation section 13 and input to the recording amplifier 14, and the recording amplification section 14 amplifies the demodulated data with a predetermined gain and then switches the head as shown in FIG. According to the signal, the tape is recorded through the head disposed on the rotating drum. At this time, the control signal generator 16 outputs a control signal to the control head in order to record a control signal as a reference for video and audio head rotation to the control track of the tape through the control head as shown in FIG. 2A, and the oscillator 17 ) Generates a clock of a predetermined frequency by oscillation and provides the clock to the formatter 11, the error correction unit 12, and the demodulation unit 13.

In addition, the capstan controller 18 controls the capstan motor driving unit 19 so that the rotation speed of the capstan motor 20 is constant so that the running speed of the tape is constant, and the signal is recorded on the tape at an accurate pitch, and the drum The control unit 21 controls the drum motor drive unit 22 to always rotate in synchronization with the phase of the normal video signal in which the rotational phase of the drum motor 23 is recorded, so that a vertical synchronizing signal such as 2a at a predetermined position on the tape is provided. Make sure they are recorded together.

Therefore, as shown in FIG. 3, the helical track 403 is formed on the magnetic tape 101 by the rotating head 104 which is rotated in synchronization with the vertical synchronization signal in the video signal, thereby recording the signal and simultaneously The control track 402 is recorded in the longitudinal direction of the tape by the head 107 with a control located at a predetermined distance with respect to the rotating head 104 to record a control signal. At this time, the FG signal detected by the capstan motor 20 is fed back to the capstan controller 18 to detect the rotational speed and phase of the tape, the FG signal and PG signal detected by the drum motor 23 is the drum It is fed back to the control unit 21 to detect the rotational speed and phase of the drum. 4 is a reproduction block diagram of a conventional digital recording and reproducing apparatus, which reproduces and amplifies a signal recorded on the tape 101 through a head 104 disposed on a rotating drum. A demodulation section 43 for demodulating the output of the reproduction amplifier section 42 to detect digital data, and an error correction section 44 for correcting errors by adding an error correction code to the digital data detected by the demodulation section 43; The deformatter 45 converts the data in which the error is corrected by the error correction unit 44 into the same digital data as at the time of recording, the demodulation unit 43, the error correction unit 44, the deformatter 45, and the capstan. The control section 46, the oscillation section 47 for providing a clock to the drum control section 51, the control signal generating section 48 for detecting the phase of the tape by reading a signal from the control track through the control head, Control to accurately trace recorded tracks The capstan motor under the control of the capstan controller 48 and the capstan controller 48 for controlling the reproduction signal of the level and controlling the phase of the tape detected by the control signal generator 48 using the capstan motor. Capstan motor drive unit 49 for driving 50, drum control unit 51 for controlling the rotational speed of the drum motor at the time of regeneration so as to obtain a reproduction signal without time axis fluctuation, control of the drum control unit 51 In accordance with the drum motor driving unit 52 for driving the motor (53).

At this time, most of the operation blocks of the digital reproducing apparatus of FIG. 4 perform the same function as the same blocks as the blocks of the recording apparatus of FIG.

4, the magnetic tape 101 is rotated in synchronization with the vertical synchronizing signal of the video signal as shown in FIG. 5A at the same frequency as the head switching pulse as shown in FIG. Drive

That is, the magnetic head 104 disposed on the rotating drum reads and reproduces a signal while traveling on a track formed at the time of recording.

The signal reproduced by the tape 101 is amplified by the reproduction amplifier 42 with a predetermined gain and then demodulated by the demodulator 43 to detect digital data.

The detected digital data is added with an error correction code in the error correction unit 44, and after the error is corrected, the digital data is converted into the same digital data as when recorded by the formatter 45 and output to the display apparatus.

At this time, the oscillator 47 generates a clock of a predetermined frequency by oscillation and provides the demodulator 43, the error correction unit 44, the deformatter 45, the capstan controller 48, and the drum controller 51. do. In this case, the capstan controller 48 controls the capstan motor 50 so that the video head accurately traces the recorded track at the time of reproduction so that the reproduction signal of the maximum level is obtained. The drum controller 51 controls the drum motor 53 so that the rotation speed of the drum motor is constant by using the clock provided from the oscillator 47 so that a reproduction signal without time axis fluctuation is obtained.

In addition, the control signal detector 46 detects the phase of the tape using the signal read by driving the control head on the control track, and outputs the phase to the capstan controller 48. The capstan controller 48 outputs the phase of the detected tape. Control using the capstan motor 50.

The FG signal detected by the capstan motor 50 is fed back to the capstan controller 48 to detect the rotational speed and phase of the tape, and the FG signal and PG signal detected by the drum motor 53 are the drum. It is fed back to the control unit 51 to detect the rotational speed and phase of the drum.

At this time, when the phase relationship with respect to the reference signal of the control signal as shown in FIG. That is, the distance x between the helical track and the control signal recorded on the tape during signal reproduction when there is no change in environmental temperature in response to signal recording becomes the same at the time of recording and reproduction as shown in FIG. Is obtained.

However, in the case where an already recorded tape is extended due to an increase in the environmental temperature, as in FIG. 7, the x distance changes to x + Δx so that the distance between the position where the control signal on the magnetic tape is recorded and the position of the helical track is Corresponding to helical tracks that do not coincide with the distance between the set position and the set position of the control head, the head at the time of recording and reproduction generates a phase error ER.

In this case, a good playback video signal cannot be obtained.

Thus, the change in x distance adjusts the position of the helical track relative to the rotating head by manually or automatically adjusting the phase with respect to the reference signal of the reproduced control signal.

Usually, such tracking adjustment is made by adjusting the tracking volume provided in the operation panel of the VTR to set the phase difference between the reference signal and the reproduction control signal.

The tape length sagging causes the angle of the track to be deformed as shown in Fig. 8, where Tr1 represents the state of the track at the time of recording and the angle of the track is? 1.

However, Tr2 is a track state at the time of reproduction, and the length of the tape is extended in the longitudinal direction due to environmental humidity, temperature rise, reproduction of another set, and the like, and the angle of the track is changed to α2 compared to the tape.

Therefore, even if the head is traced in the track direction of the normal track Tr1, it is difficult to reproduce the normal signal, and as the width of the track becomes narrower, this phenomenon greatly affects the compatibility. In addition, since only tracking phase is taken into account to solve the deviation of x distance, the head-head narrow recording progresses, and the difficulty of compatibility between the environmental factors and sets increases, and when the humidity is added to the linearity of the VTR deck, the linearity is increased. There was a difficult problem to secure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to increase the drum speed at a predetermined speed than the recording time when the tape is stretched when the tape is reproduced, and to read the same track a predetermined number of times, and then to obtain the best data. The present invention provides a digital recording and reproducing apparatus that detects data accurately, improves data reliability, and is advantageous for narrow narrow tracks.

A feature of the digital recording and reproducing apparatus according to the present invention for achieving the above object is to select whether to play the drum at 1x speed or N (N is a natural number) speed depending on whether the tape is stretched or not at the time of playing the tape. A regeneration mode selector, an oscillator for generating a clock signal of 1x speed by oscillation, a divider for dividing a clock of 1x speed generated by the oscillator into a clock of Nx speed, and according to the control of the regeneration mode selector A switching unit for selecting and outputting the 1x clock generated by the oscillator or the Nx clock generated by the divider, and a signal recorded on the tape in synchronization with the 1x clock generated by the oscillator A reproduction amplifier which reproduces and amplifies through the head, and detects digital data in the reproduction signal amplified by the reproduction amplifier. Demodulation and error correction processing according to the output of the switching unit N times the current data transmission bit rate, and reading and driving the same track output through the demodulation and error correction according to the output of the switching unit at a 1x speed. A data selector which selects and outputs an error-free data among signals read by driving at the Nx speed and a signal, and converts the data selected by the data selector into the same digital data at the time of recording in synchronization with the 1x clock provided by the oscillator; Regardless of the deformatter and the 1x regeneration mode or the Nx regeneration mode, the capstan motor speed is controlled in the same manner in synchronism with the 1x clock generated by the oscillator and the phase of the tape detected through the control track is adjusted. Capstan control means for controlling by using a, 1x regeneration of the regeneration mode selection unit According to DE N or double-speed reproduction mode is the point that is configured to control the drum means for rotating the same track as N times speed.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

9 is a block diagram of a digital recording and reproducing apparatus according to the present invention, which reproduces and amplifies a signal recorded on the tape 101 through a head 104 disposed on a rotating drum. A demodulator 93 for demodulating the output of the amplification unit 92 to detect digital data, an error correction unit 94 for adding an error correction code to the digital data detected by the demodulator 93 to correct the error, A data selector 95 for selecting and outputting data in which there is no error among signals read by driving the track at 1x speed and reading at 2x speed, and the same digital data as when the data selected by the data selector 95 is recorded. Deformatter 96 for converting the signal into a frequency converter, an oscillator 97 for generating a clock signal by oscillation, a divider 99 for dividing a clock generated by the oscillator 97 at double speed, and a 1x playback mode during tape playback. 2 to play The playback mode selector 98 selects whether to play in the fast playback mode, and the clock or divider 99 generated by the oscillator 97 is divided according to the playback mode selected by the playback mode selector 98. Generation of a control signal for detecting a phase of a tape by reading a signal from a control track through a control unit SW1 for outputting a clock to the demodulator 93, an error correction unit 94, a data selector 95, and a control head. The control unit 99-1 controls the capstan motor to have the same speed regardless of the playback mode and controls the video head to accurately trace the recorded track to obtain a reproduction signal of the maximum level. Capstan controller 99-2 for controlling the phase of the tape detected by 99-1 using a capstan motor, and capstan motor driver for driving capstan motor M under the control of the capstan controller 99-2. (99-3 ), A drum double speed control unit 99-4 for rotating the drum at 1x speed or 2x speed through the drum motor M according to the regeneration mode, and a drum motor M under control of the drum double speed control unit 99-4. It is composed of a drum motor driving unit (99-5) for driving.

In the present invention configured as described above, the playback mode selector 98 selects the 1x speed playback mode when there is no change in the environmental temperature in response to signal recording and the tape is not stretched. If is stretched, select the 2x playback mode. At this time, the selection of the 1x speed or 2x speed playback mode through the playback mode selection unit 98 may be manually selected by a user or automatically by a microcomputer.

On the other hand, the oscillator 97 generates a 1x clock by oscillation, and the divider 99 divides the 1x clock by x 2 to generate a 2x clock.

At this time, if the output of the reproduction mode selector 98 is the 1x regeneration mode, the 1x clock generated by the oscillator 97 is selected by the demodulation unit 93, the error correction unit 94, and the data selection via the switching unit SW1. The rotating head is provided to the unit 95 and is provided to the deformatter 96 and the capstan controller 99-2 directly through the oscillator 97 and synchronized with the vertical synchronization signal of the video signal at the same frequency as shown in FIG. 10A. It rotates and runs the magnetic tape 101 at the same speed as at the time of recording.

That is, the magnetic head 104 disposed on the rotating drum reads and reproduces a signal while traveling on the track formed at the time of recording at the same speed as at the time of recording.

The signal reproduced by the tape 101 is amplified by the reproduction amplifier 92 with a predetermined gain and then demodulated by the demodulator 93 to detect digital data.

Then, the detected digital data is added to an error correction code in the error correction unit 94 and the error is corrected. Then, the digital data is converted into the same digital data as when recorded by the formatter 96 through the data selection unit 95 and displayed. Output to the device.

In this case, since the drum is rotated at a normal speed, only one track is driven 51 once, so the data selector 95 performs only a buffer function because there is no data to select.

Accordingly, the capstan controller 99-2 controls the capstan motor M so as to accurately trace the track image recorded by the video head at the time of reproduction so that the reproduction signal of the maximum level is obtained, and the drum controller 99-4. Controls the drum motor M such that the rotation speed of the drum motor is constant according to the control of the regeneration mode selector 98 so that a regeneration signal without time axis fluctuation is obtained.

In addition, the control signal detection unit 99-1 detects the phase of the tape by using the signal read by driving the control head on the control track, and outputs the phase to the capstan controller 99-2. The phase of the detected tape is controlled using the capstan motor M. FIG. On the other hand, if the output of the reproduction mode selector 98 is the 2x regeneration mode, the 1x clock generated by the oscillator 97 is divided by x2 by the divider 99 to generate a 2x clock.

The switching unit SW1 is switched under the control of the reproduction mode selector 98 to convert the double speed clock divided by the divider 99 into the demodulator 92, the error correction unit 93, and the data. The divider 99 is provided to the selector 95.

At the same time, the deformatter 96 and the capstan controller 99-2 are provided with the 1x clock generated by the oscillator 97 to control the capstan motor at the same speed in the 1x playback mode or the 2x playback mode.

However, the drum double speed control unit 99-4 rotates the drum at double speed through the drum motor M according to the double speed regeneration mode signal output from the regeneration mode selector 98.

At this time, since the capstan motor is driven at 1x speed and the drum rotates at 2x speed, the magnetic head runs twice as shown in FIG. 10b.

In other words, if the rotational speed of the drum is increased at twice the speed, the envelope becomes high, thereby increasing the data size.

Therefore, the signal reproduced while traveling twice over the track formed at the time of recording is appropriately amplified by the reproduction amplifier section 92 and then input to the demodulation section 93 to detect digital data.

The detected digital data is output to the data selector 95 after an error correction code is added in the error correction unit 94 to correct an error.

At this time, the demodulation unit 93, error correction unit 94, and data selection unit 95 process data at twice the current data transfer bit rate by the double speed clock.

That is, the error correcting unit 94 output terminal can read the data once read twice at the drum 1x speed.

Therefore, the data selector 95 receives the same two times data output from the error correction unit 94 and does not produce an error when correcting the error. For example, the data selector 95 selects good data from two repeated data and deformatters 96. ), And the formatter 96 converts the selected output data into the same digital data as at the time of recording and outputs the same to the display device. As described above, according to the digital recording and reproducing apparatus according to the present invention, when a tape recorded at a drum speed of 1x speed is increased due to environmental changes, the drum speed is increased to a predetermined speed, and the same track is designated a predetermined number of times. By repeatedly reading and outputting the best data among them, the data can be detected accurately, thereby increasing the reliability of the data and having a narrow narrow track.

Claims (1)

A playback mode selection section for selecting whether to play the drum at 1x speed or N (N is a natural number) speed according to whether the tape is stretched or not, and an oscillator for generating a clock signal at 1x speed by oscillation; A divider for dividing the clock of 1x generated by the oscillator into a clock of Nx and the switching of the reproduction mode selector to select and output the 1x clock generated by the oscillator or to generate an Nx speed generated by the divider. A switching unit for selecting and outputting a clock, a reproducing amplifier unit reproducing and amplifying a signal recorded on a tape in synchronization with a 1x clock generated by the oscillation unit through a head disposed on a rotating drum; Detecting digital data from the reproduced reproduction signal and correcting an error according to the output of the switching unit. Demodulation and error correction processing at N times, and outputting the error-free data among N identical data read by driving the same track output through the demodulation and error correction unit at N times according to the output of the switching unit. A deformatter for converting the data selected by the data selector into the same digital data as at the time of recording in synchronization with the data selector provided by the oscillation unit, regardless of the 1x playback mode or the Nx playback mode. Capstan control means for equally controlling the speed of the capstan motor and controlling the phase of the tape detected through the control track in synchronization with the 1x clock generated by the oscillator; and 1x playback mode or Nx speed playback mode of the playback mode selector. Consisting of a drum double speed control means for rotating the drum at a Nx speed for the same track Digital recording and playback device.