JPH04286773A - Digital vtr - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a digital V
The present invention relates to a TR that records a time code signal representing time information on the tape-like medium and reproduces the time code signal.

0002

2. Description of the Related Art Conventionally, VTRs that digitize and record video signals include, for example, D-1 standard component VTRs and D-2 composite digital VTRs.
etc. In the D-2 standard, in addition to recording video and audio signals on helical recording tracks, audio, time code, and control (hereinafter abbreviated as CTL) signals are recorded on linear tracks formed along the longitudinal direction of the tape.

FIG. 2 shows the tape format of a D-2 VTR viewed from the recording surface side. The magnetic tape 1 runs in the direction of the arrow in the figure, and is moved onto a helical track 3 by the rotating head 2.
is formed and the signal is recorded. The helical track 3 consists of a video sector 4 where a video signal is recorded and an audio sector 5 where an audio signal is recorded. Here, an editing gap is provided between each sector to enable additional recording, so-called post-recording. Further linear tracks 9, 1 are formed on the tape by fixed heads 6, 7 and 8.
0 and 11 are formed, respectively analog audio signals and CT
The L signal and time code signal are recorded. Here C
The TL signal is a pulse signal written every time a helical track is formed for tracking control of a rotary head and tape running control, similar to analog VTRs such as VHS standard. In addition, the time code signal recorded on the linear track is LTC (Longitudinal Time
Code) and is used as an absolute address corresponding to each frame mainly when editing images. Like signals on other linear tracks, this LTC can be appended and saved independently of the helical track, and can be played back regardless of the trajectory of the rotating head even during high-speed playback, so it is especially useful for editing. Until now, this signal has been considered essential for commercial VTRs.

By the way, as is well known, the D2-VTR
Broadcasting digital VTRs, typified by the above, are large and difficult to use, and there is a strong desire for miniaturization in order to popularize them as newsgathering VTRs or future consumer VTRs. Therefore, various improvements regarding high-density recording have been made in order to reduce the amount of tape consumed and to reduce the size of the cassette and the VTR body. Television Society Journal Vol.
．． 44, No. 9, pp. 1174-1177 (199
DAT (Digital Audio Ta) described in 0)
pe Recorder) and 8mm VTR.
ding) servo is one of them, and it superimposes or inserts a pilot signal on the helical track to detect tracking deviation, making it possible to accurately track the head on a narrow track without using a CTL signal. be. Furthermore, by arranging the ATF signal recording areas at the upper and lower ends of the tape, there is also the effect of increasing the stability against damage at the tape ends compared to conventional CTL control.

[0005] Therefore, in order to realize the miniaturization of professional digital VTRs that require high-density recording, the conventional technology used in the above-mentioned consumer equipment, namely ATF servo, is adopted to perform highly accurate and stable running control. CT
Deleting redundant linear tracks such as the L track and completing the function as a VTR using only the information of the helical track is a means to reduce the size of the tape cassette, as well as linear tracks such as fixed heads and pinch rollers. By reducing the number of circuit parts involved in track recording and playback,
This is effective as a means for reducing the size of the TR itself.

[0006]

[Problem to be Solved by the Invention] However, in this case, the LTC, which is the standard for editing work on business VTRs,
If the linear track area for recording signals is deleted, the LT that the user has accumulated in the past will be deleted.
Not only will users lose their editing know-how using C, but they will also be at risk of continuing to use editing peripherals such as VTR editing controllers that are controlled using LTC, and will not be able to utilize the various software and hardware assets they own. Become.

[0007]

[Means for Solving the Problems] As a means for solving the above problems, the present invention provides a digital VT using an ATF servo.
In R, (1) A time code sector is provided on the helical track, and a time code area is secured on the linear track to enable LTC recording/reproduction.

(2) While reproducing the time code from the time code sector on the helical track, the time code is converted into the LTC format and output.

(3) A mode is provided in which recording is performed on a linear track at the same time as the above-mentioned format conversion/output to LTC.

[0010] The above three technical means will be introduced.

[0011]

[Function] Each of the above technical means has the following functions.

(1) Since the user can perform editing operations using time codes using the same procedures and equipment as before, it is possible to prevent loss of existing software/hardware assets when introducing a new format VTR.

(2) Even for tapes where time code is recorded on the helical track but LTC is not recorded, it is the same as before, and when special playback such as still and slow, interpolated LTC allows for better performance than before. Provides ease of use.

(3) By making it possible to add the time code to the linear track in sectors on the helical track, it is possible to omit the recording means to the linear track for recording-only machines such as camera-integrated VTRs. , further reduction in size and weight can be achieved.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a tape format according to the present invention, and the same reference numerals are used for parts common to those in FIG. 2 described above.

In FIG. 1(a), the helical track 3
ATF in addition to video sector 4 and audio sector 5 on top
A sector 12 for signals and a sector 13 for HTC signals are provided. The ATF sector 12 and HTC sector 13 are arranged at the upper and lower ends of the helical track 3 in the same way as the audio sector 5, and regarding the ATF servo, tracking error information is detected at two locations, the upper and lower, to ensure accuracy and to prevent damage to the tape. As for time code control, by increasing the number of discrete HTC signal samples obtained during special playback such as shuttle playback, HTC interpolation, which will be described later, is facilitated. Note that the positional relationship of the ATF sector, HTC sector, and audio sector in the figure on the helical track is arbitrary.

Regarding the linear tracks, an audio track 9 and a time code track 11 are formed by fixed heads 6 and 8, respectively. The linear tracks may be placed above and below the tape as shown in FIG. 1(a), or may be placed on one side as shown in FIG. 1(b), for example. The same audio signal as the audio sector 5 on the helical track is recorded in analog on the audio track 9, and is used as a guide for searching the tape or setting an editing point. On the other hand, the same time code signal as that in the HTC sector 13 is digitally recorded in the time code track 11 in the LTC format. If predetermined signals are recorded on these linear tracks, editing using LTC as a reference can be performed using the same procedure as before during playback, but miniaturization is particularly required for VTRs with built-in cameras, etc. If it is difficult to provide a recording circuit to the linear track due to space constraints, it may be omitted and the linear track may be left blank.
Since the TC is recorded, there is no information to be lost.

Next, FIG. 3 shows a circuit configuration of a recording system of a VTR that obtains the tape format of the present invention.

The magnetic tape 1 is wound around the cylinder 14 by the guide post 15, and comes into contact with the rotary head 2 mounted on the cylinder, the audio fixed head 6, and the LTC fixed head 8, so that the tracks shown in FIG. Record signals while forming.

Video signals, audio signals, and time code signals to be recorded are input from terminals 19, 20, and 21, respectively. The video signal is converted into a digital signal by processing such as sampling and quantization in the video input processing circuit 22, and then sent to the error correction code circuit 29. The video signal is also supplied to a reference synchronization signal generation circuit 25, which generates various synchronization signals that serve as a reference for signal recording. The microcomputer circuit 32 is a system controller that controls the entire VTR system, and supplies system information to each signal processing block. The audio signal is digitized in the same way as the video signal by the audio input processing circuit 23, and is then digitized by the error correction code circuit 29.
At the same time, the analog signal is processed by high frequency bias, etc., and the timing correction circuit 31 adjusts the recording position on the linear track, and then the recording amplifier 1
7 to the fixed head 6. Regarding the time code signal, the time code input processing circuit 24 receives an external input that undergoes processing such as waveform equalization, and the output of the time code generation circuit 27, which receives a reference synchronization signal and generates a time code synchronized with the video signal. One is selected by the switch 28, and one of the outputs is sent to the error correction code circuit 29.
The other one is supplied to the LTC fixed head 18 via the recording amplifier 18 and the timing correction circuit 31.

In the error correction code circuit 29, a code having an appropriate correction ability is assigned to each signal, and a check bit is added to each signal. The output is time-base multiplexed in the multiplexing circuit 30 together with the ATF signal including the pilot signal generated by the ATF signal generating circuit 26, and is supplied to the rotary head 2 via the recording amplifier 16.

Each block of the recording system circuit has been described above with reference to FIG. By using such a circuit, the desired tape format shown in FIG. As an example, it is also possible to omit recording on a linear track using a fixed head.

Next, the third embodiment will be explained using FIG. 5.

In this embodiment, the format of the helical track is based on FIG. 1, and for a tape with blank LTC and/or linear track audio, the HTC and/or audio signal from the helical track is simultaneously played back and recorded on the linear track. The present invention relates to a VTR for recording playback signals, and FIG. 5 mainly shows the playback system circuit block, and the same parts as the recording system blocks shown in FIGS. 3 and 4 can be used in common. The signal flow will be described below.

The signal reproduced from the rotary head 2 is sent to a separation circuit 34 via a reproduction amplifier 33, and is divided into video, audio,
Separated into time code and ATF signals. The ATF signal is sent to the servo circuit 37, and the other three signals are sent to the error correction decoding circuit 35, respectively.

The servo circuit 37 controls the motor circuit 38 based on tracking deviation information from the ATF signal. Such a control loop enables highly accurate tracing of narrow tracks in a compact digital VTR without using a CTL signal.

After error correction, the video signal is subjected to processing such as digital/analog conversion in the video output processing circuit 39 and outputted from the terminal 42.

The audio signal is also output from the terminal 43 through the same route, but at the same time is supplied to the audio fixed head 6 via the timing correction circuit 31 and the recording amplifier 17.

Regarding the time code signal, HTC/LT
The HTC data reproduced by the C conversion circuit 36 is converted to LTC.
format, the level etc. are adjusted by the LTC output processing circuit 41, and the output is output from the terminal 44.
Like the audio signal, it is divided into those supplied to the fixed head.

Here, the correction width of the audio and LTC recording positions in the timing correction circuit 31 is different from that in the case of recording shown in FIG. 3 above. To explain specifically, for example, assuming that the same data as the HTC currently being traced in FIG. 6 is to be recorded at point A as LTC, the correction circuit 31
In the case of Fig. 5, the delay time given to the TC is the value obtained by subtracting the HTC's playback processing time from the time T for point A to reach the head, but in the case of Fig. 3, the HTC's recording processing time is subtracted from the same T. It becomes something added. The microcomputer circuit 32 switches the correction width, that is, the delay time, depending on the mode.

In this way, H from the helical track
It becomes possible to simultaneously record the reproduced signal on a linear track while reproducing the TC and/or audio signal, improving usability during editing.

Next, a fourth embodiment of the present invention will be explained using FIG.

This embodiment is an applied example of the third embodiment, and has the following points: switches 45 and 46 are inserted in the paths from the timing correction circuit 31 to the fixed heads 17 and 18, respectively, and the LTC regeneration amplifier 48 The feature is that the output is supplied to the LTC output processing circuit 41 via the switch 47.

The microcomputer circuit 32 has a VT set by the user.
Switch 45 depending on the R mode and VTR operating status.
, 46, 47, controls the LTC conversion circuit 36 and the LTC output processing circuit 41, and manages recording on each linear track and LTC output from the terminal 44.

During normal playback, switches 45 and 46 are off.
f and 47 are on, and conversely, 45 and 46 are o when recording.
However, since the already recorded LTC or linear track audio is not rewritten in the insert editing mode even during recording, both of the above switches are turned off.

In addition, when the mode is in which recording to the linear track is performed at the same time as playback, the switches 45 and 46 are on, but the microcomputer circuit 32 uses the phase lock detection signal of the playback signal received from the servo circuit 37 to detect when the special playback is performed. When it is determined that the phase is not locked, that is, the VTR is not operating at a constant double speed, both switches are turned off. As a result, recording on the linear track is prohibited in a state where conversion to LTC is impossible, and erroneous recording is automatically avoided.

On the other hand, regarding the output of LTC, HTC/
If necessary, error correction/interpolation is performed depending on the mode and reproduction state set in the LTC conversion circuit 36, and an output signal is selected in the LTC output processing circuit 41. An example of the interpolation and selection algorithm will be explained using the flowchart of FIG.

The first half of the chart relates to HTC error interpolation, and the second half below st10 relates to HTC/LTC selection. First, check the playback status of the VTR (st2), and if it is normal playback, check the readability of the HTC (st3).
)do. If there is no abnormality, the flag is reset (st9), and if there is an error, the error flag is incremented by +1 (st4), and then the cumulative degree of errors is checked (st5). If the error continues for N or more times, it is considered as a new series and the flag is reset (st9), otherwise it is considered as an error and HTC is interpolated using past data (
st6).

When branching at st2 and performing special playback such as shuttle or slow, first check the phase lock of the playback signal (s
t7), and if it is not locked, it is impossible to interpolate HTC, so go to st10, and if it is locked, check the stepability (s
t8) If there is no error, interpolate the missing part (st6); if there is an error, no interpolation is performed. When branching at st2, output T is output when the state is still or when the LTC cannot be read (st10).
C is set to HTC (st12), and if there is no LTC reading error (st10), the output TC is set to LTC, and then the LTC output mode set by the user is checked (
st13). In automatic interpolation mode, output TC remains unchanged, L
In the TC direct connection mode, the output TC is set as LTC and the process ends.

As described above, in this flowchart, the algorithm gives priority to LTC, and HTC is given an auxiliary role. Here, since the interpolated LTC obtained at the time of error and special playback is generated under the condition that interpolation can be performed reliably, it is highly reliable and can be sufficiently used as a reference signal for editing work.

Finally, a fifth embodiment of the present invention will be described. FIG. 9 is a diagram showing the circuit configuration. An N-times reference synchronization signal generation circuit 49 is provided in parallel with the reference synchronization signal generation circuit 25 in the fourth embodiment shown in FIG. There are characteristics in the selected areas. The N times reference synchronization signal generation circuit 49 is
A synchronization signal with twice the frequency is generated and supplied to each part of the circuit. When the microcomputer circuit 32 selects the N-times reference synchronization signal generation circuit 49 with the switch 50, it also instructs the servo circuit 37 to rotate the cylinder and run the tape at N times;
By performing simultaneous TC playback and LTC recording at N times the speed, the work time is significantly reduced.

Note that the other circuit operations are as described in the fourth embodiment.

[0044]

Effects of the Invention (1) In a digital VTR that adopts the ATF servo system, a time code area is secured in the linear track to enable LTC recording/playback, allowing the user to use the same procedures and equipment as before. Since editing work can be done using timecode, it is possible to prevent the loss of existing software/hardware assets when introducing a new format VTR.

(2) By making it possible to record the time code in the sector on the helical track, for example, for a recording-only machine such as a camera-integrated VTR, the recording means on the linear track can be omitted, and the number of parts can be reduced further. The size and weight can be reduced.

(3) Playing timecode from the timecode sector and simultaneously outputting it in LTC format,
Furthermore, by providing a mode for writing to the linear track, it is possible to easily convert and use tapes for editing even if the time code has been recorded on the helical track but the LTC has not been recorded. Become.

[Brief explanation of the drawing]

FIG. 1 shows a recording format on tape according to the invention.

FIG. 2 is a diagram representing a conventional recording format on tape.

FIG. 3 is a circuit configuration diagram showing a first embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing a second embodiment of the present invention.

FIG. 5 is a circuit configuration diagram showing a third embodiment of the present invention.

FIG. 6 is an explanatory diagram regarding a third embodiment of the present invention.

FIG. 7 is a circuit configuration diagram showing a fourth embodiment of the present invention.

FIG. 8 is a flowchart for explaining a signal processing procedure in a fourth embodiment of the present invention.

FIG. 9 is a circuit configuration diagram showing a fifth embodiment of the present invention.

[Explanation of symbols]

2...rotating head, 3...Helical track, 6...Fixed head for linear audio, 8...Fixed head for LTC, 9...Linear audio track, 11...LTC truck, 12...ATF sector, 13...Time code sector.

Claims (7)

[Claims] Claim 1: Digitalized video signal, audio signal,
In a digital VTR that records a time code signal and a pilot signal for tracking control in a helical manner on a tape-shaped recording medium such as a magnetic tape using a rotary head, a linear track is provided along the longitudinal direction of the tape-shaped recording medium. A digital VTR characterized in that the time code signal and/or the audio signal can be recorded using a fixed head on a linear track. 2. The digital VTR according to claim 1, wherein the time code signal reproduced from the helical track is converted into the form of a time code signal reproduced from the linear track and output. Digital VTR. 3. The digital VTR according to claim 2, wherein a frame or field in which it is impossible to reproduce a time code signal reproduced from a helical track and/or a time code signal reproduced from the linear track. A digital VTR characterized in that the missing portion is interpolated using a time code signal reproduced from the helical track. 4. In the digital VTR according to claim 3, only when the playback speed can be controlled to a constant value during normal playback and during special playback such as slow and search, the time played from the helical track. A digital VTR characterized by interpolating missing parts of a code signal. 5. The digital VTR according to claim 1, 2, 3, or 4, wherein the time code signal reproduced from the helical track is converted into the form of a time code signal reproduced from the linear track and outputted. A digital VTR characterized in that a mode is provided for simultaneously recording the converted time code signal on the linear track.
. 6. The digital VTR according to claim 5, wherein the time code signal reproduced from the helical track at N times the speed (N is an integer) is converted into the form of the time code signal reproduced from the linear track. A digital VTR characterized in that a mode is provided in which the converted time code signal is recorded at N times speed on the linear track at the same time as the converted time code signal is outputted. Claim 7: Digitalized video signal, audio signal,
A digital VTR that records a time code signal and a pilot signal for tracking control in a helical manner on a tape-shaped recording medium such as a magnetic tape using a rotating head. A digital VTR characterized in that it holds a linear track area for recording a time code signal and/or an audio signal, and that no signal is recorded on the linear track during recording.