JP2894231B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a digital VTR which performs recording / reproducing by a helical scan method using a rotary cylinder having a reproducing head and a recording head independently, and performs accurate insert recording. Device for

[0002]

2. Description of the Related Art As a digital VTR, the D-1 system (4: 2: 2 component coding system) was put into practical use in 1986, and a standardization organization was established in 1993 as a recording format for consumer digital VTRs. HD Digital VCR Confe
The DVC format is summarized by rence.

[0003] In this DVC format, FIG.
As shown in the figure, the track recorded on the magnetic tape by the magnetic head of the rotating cylinder is an ITI (Insert Track Infor
mation) section, INDEX section, Audio section, and Video section, and a gap section is interposed between the sections. Here, a pilot indicating the position of the own track is recorded in the ITI section, and is not erased during editing. The INDEX section records search information such as a time code, and enables high-speed search of recorded data. The Audio section and the Video section are, of course, sections where digital audio data and digital video data are recorded. However, since the Gap section is interposed, each data can be edited independently.

When performing insert recording (recording for rewriting and editing a part of a recorded track) with a digital VTR equipped with a normal magnetic head for both recording and reproduction, the magnetic head is first set to a reproduction mode. Truck IT
Reproduce the I part, find the time when the magnetic head reaches the insert recording part after the INDEX part of the track based on the reproduction time, and switch the magnetic head to the recording mode just before the arrival time to perform insert recording. Is possible.

[0005] In this case, since the timing of insert recording for each track is managed based on the reproduction time of the ITI section, even when rewriting data recorded by a different digital VTR, the track may vary due to individual differences between devices. It is possible to prevent the insert recording position in the direction from being shifted, and to eliminate a problem that data that should not be erased is erased by overwriting or that data to be erased remains.

[0006]

In a digital VTR equipped with a magnetic head for both recording and reproduction, edit data is separately created in advance, and the edit data is overwritten on a desired track. However, a digital VTR having an editing function reproduces data recorded on a magnetic tape, performs some processing on the reproduced data with a digital signal processing circuit, and returns to the same position on the magnetic tape. Some systems record data after processing. That is, the digital VTR executes [data reproduction] → [processing of reproduced data] → [insert recording of processed data] as a series of operations.

Therefore, in the latter digital VTR,
The reproducing head and the recording head are independently arranged on the rotating cylinder, and each head is shifted in the height direction of the rotating cylinder so that the track traced by the reproducing head is delayed by the time required for processing the reproduced data. The recording head traces. In addition, MP
When recording / reproducing audio / video data compressed by a high-efficiency encoding / compression method such as the EG (Moving Picture Experts Group) method, the processing time described above increases, and the track traced by the reproducing head is reduced. The time required for the recording head to trace is equivalent to a feed time of one to several frames (four to several tens of tracks).

Accordingly, in a digital VTR having the above-mentioned editing function, a magnetic head traces one track like a digital VTR using a recording / reproducing magnetic head, and a track corresponding to the track is reproduced based on the reproduction time of the ITI section. A method of setting the timing of insert recording cannot be adopted, and utilizing that the data to be edited is assembled and recorded using a PG (Pulse Generator) signal indicating the rotation phase of the rotating cylinder as a time reference, The start timing of insert recording is set by performing time management using the number of times of detection of the PG signal and the detection timing.

However, there is naturally an individual difference between devices in this type of VTR, and when insert recording is performed on a magnetic tape assembled by another VTR based only on the PG signal, the track is The recording position in the direction shifts. That is, even if the relative opening position of the reproducing head and the recording head viewed from the axis of the rotary cylinder and the interval in the height direction are accurately set, the relative opening position of each head and the PG signal generating unit is set. Is often slightly different depending on the device. If the start timing of insert recording is set only by uniform time management based on the PG signal, data recorded assemble by one device is recorded when edited by another device The position is shifted, and accurate insert recording cannot be guaranteed.

Therefore, according to the present invention, the rotating cylinder is provided with a reproducing head and a recording head independently, and [data reproduction] → [processing of reproduction data] → [insert recording of processing data].
Is performed in a series of operations in a magnetic recording / reproducing apparatus having an editing function, which eliminates a shift of an insert recording position based on an individual difference between devices and realizes insert recording in which unintentional data erasure or residue does not occur. It was created for the purpose.

[0011]

According to a first aspect of the present invention, a rotary cylinder provided with a reproducing head and a recording head independently performs recording and reproduction of data on a magnetic tape by a helical scan method. A magnetic recording / reproducing apparatus having an editing function of performing a recording process on the data reproduced by the head and insert-recording the processed data at a stage where the recording head traces a track on which the reproduced data is recorded; First detection means for detecting a signal indicating the rotational phase of the signal, and a predetermined signal recorded at a fixed position on each track from a reproduction signal of a track traced by the reproduction head after the first detection means detects the signal. Second detecting means for detecting
A time measuring means for measuring a time from when a signal is detected by the detecting means to when a signal is detected by the second detecting means, and the step of performing the insert recording with the recording head based on the time measured by the time measuring means. (1) time setting means for setting a time from when a signal is detected by the detecting means to when insert recording is started; and that the recording head reaches a track traced by the reproducing head based on the number of signal detections by the first detecting means. A magnetic recording / reproducing apparatus comprising: a detection unit for detecting; and a recording control unit for counting the time set by the time setting unit after the detection by the detection unit and starting insert recording by the recording head. .

In a second aspect based on the first aspect, the first detecting means and the second detecting means detect signals a plurality of times before the recording head reaches the track traced by the reproducing head, and The measuring means measures the time from the signal detection of the first detection means to the signal detection of the second detection means at each time, and the time setting means calculates the average value of the time measured by the time measurement means at each time. The present invention also relates to a magnetic recording / reproducing apparatus which sets a time from when a signal is detected by the first detecting means to when insert recording is started in a step of performing insert recording with the recording head based on the average time.

[0013]

[Action]

Regarding the first invention, the time measuring means measures a time difference between signal detection by the first detecting means and the second detecting means, and the reproducing head of the rotary cylinder actually inserts the signal based on the signal detection by the first detecting means. The time required to reach a certain position on the track to be recorded is determined. That is, the measurement time gives correlation information between the data position pre-assembled on the magnetic tape and the rotation phase of the rotary cylinder. Therefore, based on the measured time, it is possible to determine the time from when the signal is detected by the first detection means at the stage where the recording head traces the track traced by the reproduction head until the recording head reaches the insert recording position, In the present invention, the time setting means plays the role.

In this magnetic recording / reproducing apparatus, the reproducing head and the recording head do not trace the same track within one rotation of the rotary cylinder, but need to process reproduction data of the track traced by the reproducing head. After a lapse of time, the recording head traces the track, during which the rotating cylinder rotates a plurality of times and the magnetic tape is fed by a plurality of tracks. Therefore, in the present invention, the detection means detects the elapse of the delay time based on the number of detections by the first detection means, and confirms that the recording head has reached the track traced by the reproduction head.

Then, after the detection means detects the fact, the recording control means starts the insert recording by the recording head when the time set by the time setting means is counted. Therefore, the recording start timing by the recording head is set based on the data position of the track to be actually subjected to the insert recording, and even if the assembling recording is performed on the magnetic tape by different devices, the individual Accurate insert recording can be realized without being affected by the difference.

Regarding the second invention; in the first invention, the rotating cylinder rotates a plurality of times until the recording head reaches the track traced by the reproducing head. Therefore, when jitter occurs in the rotation of the rotary cylinder, if the time setting means sets the time related to the start timing of the insert recording using only one measurement time by the time measuring means, the influence of the jitter is reduced. In some cases, the timing may not be appropriate.

According to the present invention, each time the first detecting means and the second detecting means detect a signal, the time measuring means measures the difference between the detection times, and the time setting means obtains the average value of the respective detecting time differences. Is set from the time when the signal is detected by the first detecting means to the time when the insert recording starts. Therefore, even if there is a jitter in the rotation of the rotary cylinder, the influence can be reduced because the average time is obtained,
More accurate insert recording can be performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described below in detail with reference to FIGS. First, FIG. 1 shows a system configuration diagram (A) of a VTR for recording and reproducing data in a format similar to the DVC format by a helical scan method using a rotary cylinder provided with a reproducing head and a recording head independently, and the same model as the VTR. Other V that is
FIG. 4B shows a track configuration diagram (B) on a magnetic tape assembled and recorded by TR. Referring to FIG. 1, reference numeral 1 denotes a rotary cylinder on which read heads Pa and Pb for one channel and recording heads Ra and Rb are mounted; 2, a magnet mounted on the rotary cylinder 1;
A head 4 indicates a rotary transformer for extracting signals from the reproducing heads Pa and Pb and supplying the signals to the recording heads Ra and Rb. The reproducing heads Pa and Pb and the recording head Ra facing each other.
And Rb relative opening angle position from the axis of the rotary cylinder 1 are
Sufficient mounting accuracy is guaranteed, or the accuracy is compensated in a circuit by a signal reproducing / recording system described later.

The circuit of the signal reproducing system includes reproducing heads Pa and Pb.
A pulse amplifier 5, a switch circuit 6 for switching heads, a waveform equalizer 7, a decoder 8, and a demodulator 9. The demodulated reproduced signal is a digital signal processing circuit 10.
Is processed. The signal recording system includes a buffer memory 11 for temporarily storing encoded recording data processed by the digital signal processing circuit 10, a modulator 12 for modulating the encoded recording data, and a switch circuit 13 for switching the head. And a pulse amplifier 5 corresponding to the recording heads Ra and Rb. A modulated recording signal is supplied to the recording heads Ra and Rb via the rotary transformer 4. Reference numeral 21 denotes an operation unit that performs mode setting and editing instructions for the system, 22 denotes a system control unit that executes control of the entire system, and 23 denotes rotation of a rotary cylinder using a PG signal and a FG (Frequency Generator) signal (not shown). This is a servo circuit that performs control and magnetic tape feed control.

In this VTR, when the insert recording / editing mode is instructed from the operation unit 21, the track data of the magnetic tape 31 on which the assemble recording is performed are read and reproduced by the reproducing heads Pa and Pb, and the digital signal processing is performed. After performing predetermined processing in the section 10, the reproducing heads Pa and Pb
Has an editing function of overwriting the processed data on the reproduced track by the recording heads Ra and Rb.
For this purpose, the reproducing heads Pa, Pb
And the recording heads Ra and Rb corresponding thereto have a predetermined opening angle θ.
The read heads Pa, Pb and the recording heads Ra, Rb are also shifted with respect to the height direction, and the tracks of the magnetic tape traced by the read heads Pa, Pb are recorded. The time required for the heads Ra and Rb to trace is longer than the data processing time in the digital signal processor 10.

As shown in FIG. 1, the system of this embodiment is characterized by a microcomputer circuit (hereinafter referred to as a "microcomputer circuit") for controlling the timing of insert recording when an insert recording / editing mode is instructed.
41 and two timers 42 and 43 are provided. Then, the microcomputer circuit 41 outputs the PG detected by the PG head 3.
Using the signals and the ITI signal reproduced from the track of the magnetic tape 31, the timers 42 and 43 are used and the magnetic tape 31 is used.
The timing of insert recording with respect to is controlled, and the control procedure will be described in the following first and second embodiments. However, as shown in FIG.
Assemble recording is performed so that data for one frame is composed of tracks, and in insert recording in the following embodiment, recording data up to frame [n-2] in FIG. A case will be described as an example in which editing is performed on a frame basis for [n-1] and [n].

<< Embodiment 1 >> The control procedure according to this embodiment is shown in the flowcharts of FIGS. First, FIG.
Shows a procedure for setting the insert recording timing. In this case, the insert recording mode is set in advance, the editing target ranges are frames [n-1] and [n], and the data processing procedure for the editing is input from the operation unit 21. The digital signal processing circuit 10 stores the data and the program transferred from the system control unit 22.

The track data is read by the read heads Pa and Pb while the rotary cylinder 1 rotates while the magnetic tape 31 is being fed, and the read signal is transmitted from the rotary transformer 4 to a digital signal via a signal reproducing circuit. Transferred to the processing circuit 10 and usually a digital signal processing circuit
In step 10, the reproduction data subjected to the predetermined processing is output to a monitor side circuit (not shown). In the reproducing state, the rotational phase of the rotary cylinder 1 is detected from the PG signal, and the switching circuit 6
While reproducing the audio / video data of the tracks sequentially traced by the reproducing heads Pa and Pb.

In this embodiment, the microcomputer circuit
41 constantly detects the PG signal obtained from the PG head 3, and if there is the detection, sets the timer 42 to start time counting (S1, S2). Since the reproducing head Pa traces the track immediately after the detection of the PG signal, the data read from the track is input to the digital signal processing unit 10. The detection of the ITI signal from the processing unit 10 is confirmed. In that case, the digital signal processing unit 10
Confirms whether the ITI data reproduced based on the editing target range data stored in advance is related to frames [n-1] and [n], and if they are those frames, the fact is confirmed. Also notifies the microcomputer circuit 41.

On the other hand, in the microcomputer circuit 41, when the digital signal processor 10 confirms the detection of the ITI unit, the timer 42
Is saved (S3, S4). Then, when receiving the above notification from the digital signal processing unit 10,
The insert recording timing is set based on the saved Ti, the saved Ti is cleared, and the timer 42 is set.
Is reset (S5 to S7). If an ITI portion that is not a frame to be subjected to insert recording is detected, the saved Ti is saved without setting the insert recording timing.
Is cleared and the timer 42 is reset to wait for the detection of the next PG signal (S5 → S9 → S1).

Here, the time Ti gives a time difference from the detection time of the PG signal to the detection time of the ITI part recorded at a fixed position on the track. Since the relative recording positions of the recording heads are constant, using the time Ti and the rotation speed Vc of the rotary cylinder 1, the INDEX part, the audio part, and the video part by the recording heads Ra and Rb based on the detection point of the PG signal. Can be set for the insert recording timing.
However, the timing is set as the timing of reading the insert recording data from the buffer memory 11 and the timing of the operation period of the pulse amplifier 5. The set timing gives the recording timing for the position of the INDEX part, Audio part and Video part of the track based on the detection timing of the ITI part actually recorded on the magnetic tape 31. Even if there is an individual difference between the recorded VTR and the VTR performing the insert recording, the time information is not affected by the individual difference.

Thereafter, after detecting the PG signal, the microcomputer circuit 41 counts the number of times the PG signal obtained from the PG head 3 has been detected. When four PG signals are detected, the timer 42 is reset and the timer 42 is reset. Is repeated (S8 → S2). That is, it is determined whether or not the frame is to be subjected to insert recording on a frame-by-frame basis. If the frame is to be subjected to insert recording, the operation of setting the timing of insert recording for that frame is repeated.

FIG. 3 shows a procedure for performing insert recording by the recording heads Ra and Rb at the timing set in the above procedure. The timing set in S6 in FIG. 2 is obtained by the reproduction head Pa reproducing the first track of the frame to be subjected to insert recording, and the recording head Ra inserts the frame with respect to that frame. Recording is possible when the PG signal is detected four times (when the magnetic tape 31 advances by one frame).
Because. Therefore, the recording becomes possible only in FIG.
This corresponds to the point in time when the PG signal is detected four times in S8 and the procedure is recursed.

In this insert recording procedure, the insert recording timing is set (S6) in FIG. 2, and when the PG signal is detected four times (S8), the microcomputer circuit 41 sets the timer 43 (S11 to S11). S14), referring to the count time of the timer 43, read the processed data from the buffer memory 11 based on the previously set insert recording timing, and perform the insert recording for one track by the recording head Ra. (S15). Naturally, the track on which the insert recording is performed is a track traced by the recording head Ra immediately after four PG signals are detected, and is the first track of a frame to be subjected to insert recording.

When the insert recording for one track is completed, the microcomputer circuit 41 resets the timer 43, resets the timer 43 when the next PG signal is detected, and performs the same procedure as described above. Next, insert recording for the second track is executed by the recording head Rb.
(S15, S16 to S19 → S14, S15). Then, in the same manner, the third and fourth tracks are set to the recording head Ra.
And Rb are sequentially recorded (S14 to S19 → S14), and when the fourth track is recorded and the timer 43 is reset, it is confirmed again whether the insert recording timing is set and whether the PG signal is detected four times. (S11, S12), and recording for the next frame to be inserted is performed (S13, S14 to S19).
→ S14).

The relationship between the insert recording timing setting procedure in FIG. 2 and the insert recording procedure in FIG.
This will be specifically described with reference to FIGS. 4 and 5 showing signal detection timing, a reproduction signal pattern of each track, and ITI detection timing. 4 and 5, the positional relationship between the reproducing heads Pa and Pb and the recording heads Ra and Rb is shown linearly within the two-dot chain line in correspondence with the time scale at which the above-mentioned signals appear. Also, the detection interval of the PG signal:
Δtp (m) of Tp + Δtp (m) [m = 1 to 10] takes into account the jitter of the rotational speed generated in the rotating cylinder 1 of the VTR performing reproduction and recording. From detection of ITI detection signal to time: Ti [f] + Δti (m)
Δf i (m) of [f = n−2, n−1, n] is the variation due to the above Δtp (m) and the rotation speed generated in the rotary cylinder 1 of the VTR that has assembled and recorded on the magnetic tape 31. Although jitter is taken into account, Δtp (m) and Δti (m) are generally VTR
Is smaller than the difference in Ti [f] generated due to the individual difference of.

In the state of FIG. 4, the reproducing head Pa reproduces the first track of the frame [n-1] to be edited,
At this stage, the microcomputer circuit 41 sets Ti = Ti [n-1] + Δti (5)
The playback data of the track is sequentially played back, subjected to a predetermined processing by the digital signal processing circuit 10, and then stored in the buffer memory 11 as shown in FIG. As described above, the recording head Ra is moved by the feeding of the magnetic tape to the frame.
When the first track of [n-1] is reached, insert recording is performed by the recording head Ra. The interval corresponds to the time during which four PG signals are detected, and the insert recording in the track direction is managed by the insert recording timing set based on Ti. On the other hand, the second / third / fourth of frame [n-1]
The third track is reproduced by the reproducing heads Pb / Pa / Pb, however, the reproduced data thereof is not an object for obtaining Ti, and is processed by the digital signal processing circuit 10 sequentially and then stored in the buffer memory 11. At the stage when the recording head Rb / Ra / Rb reaches these tracks after the PG signal is detected, insert recording is performed on each track by the same time management as described above.

Attention is now directed to FIG.
When a completes recording on the first track of frame [n-1], it means that the reproducing head Pa has already reproduced the first track of frame [n], and the recording head Ra has Until the insert recording for the frame [n-1] is completed, a new Ti = Ti [n] + Δti (9) in the procedure shown in FIG.
Is set, and the timing of insert recording for frame [n] is set. Therefore, by repeating the procedure of FIG. 2 and FIG. 3, the INDEX processed by the digital signal processing circuit 10 is set for the subsequent frames while setting the insert recording timing based on the detection of the PG signal and the ITI signal. It is possible to accurately overwrite the data of the unit, the audio unit, and the video unit at the data position of each unit in which the original assembly recording has been performed.

According to this embodiment, since the insert recording timing is set for each frame based on the data position actually recorded on the magnetic tape 31, the frames are assembled and recorded by different VTRs. However, even if they are recorded, accurate insert recording can be realized without being affected by individual differences existing between those VTRs and the VTR that executes this insert recording. In this embodiment, Ti is detected on the first track on which insert recording is performed. However, if the ITI cannot be properly reproduced on the first track, the second track is detected.
Ti may be obtained in any of the fourth to fourth tracks.

Second Embodiment In the first embodiment, the timing of insert recording is determined only from the first track of the frame to be subjected to insert recording. However, as described above with reference to FIGS. 4 and 5, the detection interval of the PG signal: Tp fluctuates by Δtp (m) due to the jitter of the rotation speed of the rotary cylinder 1, whereby the PG signal is detected. The time from detection to the detection of the ITI detection signal: Ti [f] also fluctuates by Δti (m). Example 1
On the premise that Δti (m) is smaller than the difference in Ti [f] based on the individual difference between VTRs, Ti is obtained only in the first track of a frame, and insert recording for the frame is performed. However, if a large jitter occurs in the rotary cylinder 1 at the stage where the reproducing head Pa traces the track, Δ
Due to the influence of ti (m), there is a case where an accurate insert recording timing is not required.

Therefore, in this embodiment, the influence of Δti (m) is reduced by executing the insert recording timing setting procedure as shown in the flowchart of FIG. First, when the PG head 3 detects the PG signal, the timer 4
When the value 2 is set and the ITI obtained from the reproducing head Pa is reproduced, the count value Ti of the timer 42 is saved as in the case of the first embodiment (S21 to S25). However, in this embodiment, when it is confirmed that the reproduced ITI data is related to the frame to be subjected to the insert recording as in the first embodiment, the timing of the insert recording is immediately set using the Ti. Instead, Ti is determined every time three subsequent PG signals are detected, and a total of four Tis are detected.
Is obtained, the average value of each Ti [Ti (1) to Ti (4)]: T
iav is calculated (S21-S28 → S29).

As in the case of the first embodiment, the timing of insert recording is set based on the average value: Tiav, and when the timing setting is completed, Tiav is cleared and the timer 42 is reset, and the next frame is set. The process shifts to the timing setting procedure (S30, S31 → S21). On the other hand, the insert recording procedure is the same as the procedure shown in FIG. 3 in the first embodiment, and the insert recording is executed by applying the timing set based on Tiav by detecting the PG signal four times.

In this case, in this embodiment, the reproducing head Pa
Since the timing of insert recording is set after detecting the ITI portion of the fourth track, the time from timing setting to insert recording is shorter than in the first embodiment. However, since the calculation of Tiav and the timing setting are obtained by simple calculations, it is possible to secure a sufficient time margin and shift to insert recording. In this embodiment, since the timing of insert recording is set based on the average value: Tiav, the influence of the jitter of the rotation speed of the rotary cylinder 1 can be suppressed, and the timing can be set more accurately than in the first embodiment. Thus, more accurate insert recording can be realized. In this embodiment, the Tiav is calculated by using the reproduced signals of the ITIs of all the tracks (four) constituting one frame. However, if the ITI cannot be reproduced properly, for example, one of the four is used. When a book cannot be reproduced, an average value obtained from the remaining three tracks may be used.

[0039]

According to the magnetic recording / reproducing apparatus of the present invention having the above-described structure, the following effects can be obtained.
According to a first aspect of the present invention, there is provided a magnetic recording / reproducing apparatus for recording / reproducing data on a magnetic tape by a helical scan method using a rotary cylinder having a reproducing head and a recording head independently provided, wherein the assembled recording data reproduced by the reproducing head are provided. When the recording head performs an editing function to insert and record the processed data at the stage of tracing the track on which the reproduced data is recorded, a signal indicating the rotation phase of the rotating cylinder and a fixed value on the magnetic tape are used. Since the timing of the insert recording is set based on the detection time difference of a predetermined signal such as ITI recorded at the position, even if there is an individual difference between the device that performs the assembling recording and the device that performs the insert recording, the Accurate insert recording that is not affected is possible, and unintended data due to misalignment of recording position It is possible to prevent the removed by and data residual. According to the second aspect of the present invention, the detection time difference between the signal indicating the rotation phase of the rotary cylinder and the predetermined signal such as ITI is measured a plurality of times, and the insert recording timing is set based on the average value. This prevents the occurrence of an error in the above-mentioned timing setting due to the jitter of the rotation speed, and enables more accurate insert recording.

[Brief description of the drawings]

FIG. 1 shows a VT according to an embodiment of a magnetic recording / reproducing apparatus of the present invention.
FIG. 3A is a diagram of a system configuration of R (A) and FIG. 3B is a diagram of a track configuration on a magnetic tape assembled and recorded by another VTR of the same model as the VTR.

FIG. 2 is a flowchart illustrating an insert recording timing setting procedure according to the first embodiment.

FIG. 3 is a flowchart showing an insert recording procedure.

FIG. 4 is a signal timing chart showing a detection timing of a PG signal, a reproduction signal pattern of each track, and a detection timing of an ITI at a stage of setting a timing of insert recording. The positional relationship between the reproducing heads Pa and Pb and the recording heads Ra and Rb is shown linearly within the two-dot chain line in correspondence with the time scale at which each signal appears.

FIG. 5 shows the timing of detecting a PG signal at the start of insert recording, the reproduction signal pattern of each track, and the ITI.
6 is a signal timing chart showing the detection timing of. The read heads Pa and Pb and the write heads Ra and Rb are set in the two-dot chain line in accordance with the time scale at which each signal appears.
Are linearly shown.

FIG. 6 is a flowchart illustrating an insert recording timing setting procedure according to the second embodiment.

[Explanation of symbols]

1 ... rotating cylinder, 2 ... magnet, 3 ... PG head (1st
Detection means), 4 ... rotary transformer, 5 ... pulse amplifier, 6,13 ... switch circuit, 7 ... waveform equalizer, 8 ... decoder,
9 demodulator, 10 digital signal processing circuit (second detection means), 11 buffer memory, 12 modulator, 21 operation unit, 2
2 ... system control unit, 23 ... servo circuit, 31 ... magnetic tape, 41 ... microcomputer circuit (first detecting means, second detecting means, time measuring means, time setting means, detecting means, recording control means), 4
2, 43 ... timer (42; time measuring means, 43; recording control means), P
a, Pb: reproduction head; Ra, Rb: recording head.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 27/036 G11B 15/467 G11B 5/09

Claims (2)

(57) [Claims] 1. A recording / reproducing apparatus for recording / reproducing data on a magnetic tape by a helical scan method using a rotary cylinder provided with a reproducing head and a recording head independently of each other. A magnetic recording / reproducing apparatus having an editing function of insert-recording the processed data at a stage where the recording head traces a track on which the reproduced data is recorded, wherein a signal indicating a rotation phase of the rotary cylinder is detected. A first detection unit, a second detection unit that detects a predetermined signal recorded at a fixed position on each track from a reproduction signal of a track traced by the reproduction head after the first detection unit detects a signal, Time measuring means for measuring a time from when a signal is detected by the first detecting means to when a signal is detected by the second detecting means; A time setting means for setting a time from a signal detection of the first detection means to a start of insert recording in a step of performing insert recording by the recording head based on the time measured by the measurement means; and Detecting means for detecting that the recording head has reached the track traced by the reproducing head based on the number of signal detections, and counting the time set by the time setting means after the detection by the detecting means, and performing insertion by the recording head. A magnetic recording / reproducing apparatus comprising a recording control means for starting recording. 2. The first detecting means and the second detecting means detect a signal a plurality of times until the recording head reaches the track traced by the reproducing head, and the time measuring means detects the first detection in each time. The time from when the signal is detected by the means to when the signal is detected by the second detection means is measured, and the time setting means obtains an average value of the times measured by the time measurement means, and the recording is performed based on the average time 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a time from when a signal is detected by the first detection means to when insert recording is started in the step of performing insert recording with a head is set.