JP2517333B2 - Reproduction method of rotary head type tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an area division type ATF (Automatic Track F) such as a rotary head type digital audio tape recorder.
The present invention relates to a reproducing method of a rotary head type tape recorder for controlling reproducing tracking by means of inding), and more particularly to a reproducing method of a magnetic tape recorded at a speed half the standard speed.

[Conventional technology]

Conventionally, the rotary head type digital audio tape recorder (hereinafter referred to as R-DAT) is, for example, 109-117 in the April 1987 issue of the magazine "TV Technology" (published by Electronic Technology Publishing Co., Ltd.) (Vol. 427). Page, 11 of March 1987 issue of "Electronic Life" magazine (published by Japan Broadcasting Corporation)
As described on page 66, a pair of rotating magnetic heads of opposite azimuths installed 180 ° apart on the periphery of the rotating drum (head cylinder) are used to rotate the magnetic field around the drum by 90 °. The tape is helically scanned, and at the time of recording, a track (A) in which a digital audio signal (PCM audio signal), an ATF signal for tracking control, etc. are recorded by an area division type format shown in FIG.
(B) is sequentially formed on the tape (T) without a guard band.

Note that the tracks (A) and (B) indicate azimuth tracks of a pair of heads, respectively, and are formed by overlapping recording of half the track width W by both heads, and the track width W is the gear length (track length) of both heads. Width) is set to 2/3.

In addition, each track (A), (B) consists of 196 blocks with a signal recording length of 288 bits as a unit, and
The 1st sub code area (SUB
1), 1st ATF area (ATF1), PCM area (PCM), 2nd ATF
Area (ATF2) and second subcode area (SUB2) are time-divided, PCM audio signal is recorded in PCM area (PCM), and first, second subcode area (SUB1),
Audio and video digital signals (PC
M signal) is recorded and the first and second ATF areas (ATF1), (ATF
ATF signals such as sync signals and pilot signals necessary for tracking control during reproduction are recorded in the 4-track complete type format described below in 2).

By the way, the first and second ATF areas (ATF1), (ATF2) are 5
The block length is set, and the ATF signal is a pilot signal with a single frequency f ₁ (= 130.67KHz) for tracking.
A synchronization signal for sampling preparation, which sequentially changes to two frequencies f ₂ and f ₃ for each track, and a single frequency f ₄ (= 1.
568MHz) so that the crosstalk component of the pilot signal from two adjacent tracks can be sampled with reference to the detection of the trace track sync signal.
Time-division recording is performed by a repeating pattern in which the recording length and recording order are changed in four track cycles.

The frequencies f ₂ and f ₃ of the synchronizing signal are f ₂ = 522.67 KHz when the so-called positive azimuth track (A) and f ₃ = 78 when the negative azimuth track (B).
It becomes 4.00KHz.

In addition, the type of recording length of each signal is
Then, five types of 0.5τ, 1τ, 1.5τ, 2τ, 2.5τ are set.

Then, the continuous 5 tracks (B ₀ ) in FIG. 8 in which the first and second ATF areas (ATF1) and (ATF2) are enlarged,
(A ₁ ), (B ₁ ), (A ₂ ), and (B ₂ ) will be used to explain the 4-track complete type format. In the first track (B ₀ ), in the area (ATF1), f ₃ Sync signal, erase signal, and pilot signal of 1 from the trace start side in order
Area (ATF2) recorded in the length of τ, 2τ, 2τ respectively
If the pilot signal, the erase signal, the sync signal of f ₃ , and the erase signal are respectively recorded in order of 2τ, 1τ, 1τ, 1τ from the trace start side, the second track (A ₁ ) is
The area (ATF1), pilot signals, erase signals, the synchronization signal f _2, the erase signal, 2.tau from the trace starting end side in this order, 1
Area (ATF2) recorded in the length of τ, 1τ, 1τ respectively
At f _2, the sync signal, the erase signal, and the pilot signal of f ₂ are recorded in order of 1τ, 2τ, 2τ from the trace start side.

The third track (B ₁ ) is the area (ATF1)
The sync signal, erase signal, and pilot signal of f ₃ are recorded in order of 0.5τ, 2.5τ, and 2τ from the trace start side, respectively, and the pilot signal, erase signal, and f ₃ of area 3 (ATF2) are recorded. The sync signal and the erase signal are recorded in order of 2τ, 1τ, 0.5τ, and 1.5τ from the trace start side.

Furthermore, the fourth track (A ₂ ) is the area (ATF 1)
, The pilot signal, the erase signal, the sync signal of f ₂ and the erase signal are recorded in order of 2τ, 1τ, 0.5τ, 1.5τ from the trace start side, respectively, and the sync of f ₂ is recorded in the area (ATF2). The signal, the erase signal, and the pilot signal are recorded with a length of 0.5τ, 2.5τ, 2τ from the trace start side.

The fifth track (B ₂ ) is in both areas (ATF
The recording pattern of (1) and (ATF2) is the first track (B
It becomes the same as the recording pattern of areas (ATF1) and (ATF2) of ₀ ).

A 3τ gear gap (IBG) for inter-area margin is provided between each of the areas (ATF1) and (ATF2) and the PCM area (PCM).

At the time of reproduction, the head tracing of both heads is controlled by the tracking control described below.

That is, since the gear length of both heads is 1.5 times the width W of each track (A), (B), the reproduced signal of both heads usually contains the signal component of the trace track and two adjacent tracks of the trace track. The crosstalk component from is included.

Then, in the on-track state in which the levels of both crosstalk components change according to the trace position and the head center and the track center match, the levels of both crosstalk components become equal.

Further, as is apparent from FIG. 8, the tracks (A) and (B) are run by running the tape (1) in the same direction as during recording.
During normal playback in which both areas (ATF1) and (ATF2) are traced, the pilot signal of the trailing track on the right side crosstalks during tracing of the sync signal part of the trace track, and the left side after tracing the sync signal part. The pilot signal of the leading side track of is cross-talked.

Furthermore, the determination of the next trace head and the prediction of the frequency of the synchronization signal of the ATF areas (ATF1) and (ATF2) of the next trace track are performed by the head switching pulse signal (RFSW signal) which inverts the level every half rotation of the head cylinder. ).

Therefore, at the time of reproduction, based on the discrimination of the trace head based on the RF pulse signal and the prediction of the frequency of the sync signal of the trace track, during the trace of each track,
Based on the detection of the sync signal of each of the ATF areas (ATF1) and (ATF2), the crosstalk components of the pilot signals from both areas (ATF1) and (ATF2) of the adjacent two tracks are sampled and extracted, and , And calculates a level difference between the two crosstalk components to form a tracking control signal proportional to the level difference, that is, a tracking error signal.

Furthermore, since the level of the tracking error signal changes according to the deviation of the trace positions of both heads,
Based on the tracking error signal, the running phase of the tape (T) is controlled, both heads are pulled into the on-track position, and head tracing is controlled.

By the way, the recording and reproducing of the R-DAT are usually performed at the tape running speed and the drum rotating speed of 8.150 mm / sec and the running speed and rotating speed in the standard mode of 2000 rpm, that is, the standard running speed and the standard rotating speed, respectively. But option 2
The tape running speed and drum rotation speed are the standard running speed and 1 / of the standard rotation speed only in the long time mode called
2 times 4.075 mm / sec and 1000 rpm, respectively, and double time recording is performed.

Therefore, the playback of the tape recorded in the long time mode,
In other words, playback in the long-time mode is performed with the tape running speed set to the specified running speed of 4.075 mm / sec in the long-time mode, which is the same as that during recording. At this time, the R-DAT standard also sets the drum rotation speed at the time of recording. It is supposed to be performed at the same rotation speed in the long time mode.

However, when playing in the long-time mode, if the playback is performed at the specified running speed and specified rotation speed in the same long-time mode as during recording, the relative speed between the tape and the head is 1/2 of that in the standard mode.
Therefore, the frequency of the reproduction signal of both heads also drops to 1/2 of the standard mode.

Therefore, if you set the characteristics of the electromagnetic conversion system such as head and rotary transformer, and the characteristics of the reproduction circuit system such as the reproduction amplifier and reproduction equalizer circuit based on the characteristics of the standard mode recording and reproduction signal, At the time of reproduction, electromagnetic conversion processing, reproduction equalizer processing, etc. are not performed in the best state, and tracking control error occurs, and good reproduction cannot be performed.

Therefore, when the drum rotation speed is set to the specified rotation speed in the long-time mode during long-time mode reproduction, it is necessary to change the characteristics of the electromagnetic conversion system, the reproduction equalizer, etc. from the characteristics of the standard mode. In this case, various inconveniences such as a complicated structure occur.

Therefore, in Japanese Utility Model Laid-Open No. 62-55205 (G11B 5/09), etc., when playing in the long time mode, the tape running speed is set to the specified running speed in the long time mode, and the drum rotation speed is set to the long time mode. Of the specified speed, that is, by changing to the standard speed,
It is described that reproduction can be performed without switching the characteristics of the reproduction circuit system from the characteristics of the standard mode.

In this case, since the drum rotation speed during playback is twice as fast as during recording, head tracing is performed at twice the normal speed in the long-time mode, and the tape is repeated at approximately the same position on both heads. It is traced and the tape is played back by the so-called double scan method.

Therefore, it becomes difficult to perform tracking control using the above-mentioned ATF signal. In the above-mentioned publication, the reproduced PCM audio signal and sub-information PCM signal are reproduced based on error detection without performing tracking control. It is described that the one with few errors such as is selected and processed.

[Problems to be solved by the invention]

By the way, when the reproduction is performed without performing the tracking control as described above, the trace positions of both heads are momentarily changed due to the tracking deviation, and the reproduction levels of both heads are both lowered, resulting in a significant error rate of the reproduction signal. When such a situation occurs continuously, it becomes impossible to play back PCM audio signals, etc.
There is a problem that good reproduction cannot be performed.

And, the present invention has been made with the above problems in mind, and when reproducing in a long time mode of a rotary head type tape recorder for controlling reproduction tracking by an area division type ATF such as R-DAT, It is a technical object to perform tracking control by the tape reproduction of the double scan method so that excellent reproduction can be performed.

[Means for solving problems]

The technical means for solving the above problems will be described below.

According to the present invention, a pair of rotating magnetic heads of mutually opposite azimuths provided 180 degrees apart from each other on the periphery of the rotating drum,
Helical scan of a magnetic tape running around the drum at a certain angle, and at the time of recording, a track narrower than the gap length of both heads is sequentially formed on the magnetic tape without a guard band.
At least one sampling reference sync signal and tracking pilot signal are recorded in one or more positions of each track in an ATF area recorded in a repeating pattern of several track periods, and the sync signal of the trace track is detected during reproduction. , The crosstalk component of the pilot signal from each of the two tracks adjacent to the track is sampled, a tracking control signal proportional to the level difference between the two crosstalk components is formed, and held until the next sampling. At the same time, the tape traveling phase is controlled by the control signal to perform the tracking control of both heads. In the reproducing method of the rotary head type tape recorder, the tape traveling speed, the drum rotational speed are the standard traveling speed, and the standard rotational speed is 1 It is recorded in the long time mode set to / 2 When reproducing a magnetic tape, the tape running speed is set to 1/2 of the standard recording running speed to the specified running speed of the long time mode, and the drum rotation speed is set to twice the specified running speed of the long time mode. The technical means is set such that the standard rotation speed is set and the sampling is stopped for the next two traces every two consecutive traces.

[Action]

Therefore, according to the present invention, during the reproduction in the long time mode, the rotary drum rotates at the standard rotation speed, and the double scan system reproduction is performed. At this time, when the two heads are at the specified rotation speed, Since the tape is traced (skimmed) at twice the speed, the trace position moves by about half of the standard playback speed and standard speed of normal playback.

Then, the sampling of the tracking error signal is stopped for every two consecutive traces during the next two traces, so that the tracking error signal is sampled for every two consecutive traces every two traces and the tracking control is performed on both heads. At this time, by the servo control of the tracking position based on the tracking error signal, the tracking control is performed so that both heads are almost in the on-track state in two of the four continuous traces.

Therefore, by the double scan method reproduction, the tracking control is performed and good reproduction can be performed, and the technical problem is solved.

〔Example〕

Next, the present invention will be described in detail with reference to FIGS. 1 to 6 showing one embodiment when applied to an R-DAT.

FIG. 1 shows a block of tracking control. In FIG. 1, (1) is a reproduction input terminal for inputting a reproduction signal of both rotary magnetic heads via a rotary transformer and a head switching switch, and (2) is an input terminal ( 1 is a reproduction amplifier connected to 1), 3 is a low-pass filter for extracting pilot signals connected to the amplifier 2, and 4 is an envelope detection circuit connected to the filter 3.

(5) is a first sample and hold circuit connected to the detection circuit (4), and samples the input signal by the sampling pulse SP1. Reference numeral (6) is a subtracter for calculating the level difference between the hold signal of the sample hold circuit (5) and the output signal of the detection circuit (4), which is composed of a differential amplifier. (7) is a second sample and hold circuit connected to the subtractor (6), which samples the input signal by the sampling pulse SP2 and outputs the output signal as a tracking control signal, that is, a tracking error for tape running phase control. A signal is output from the control output terminal (8) to the drive circuit of the capstan motor.

(9) is a reproduction equalizer circuit for waveform equalization connected to the amplifier (2), and (10) is a digital conversion comparator for binarizing the output signal of the equalizer circuit (9), which is a zero-cross comparator. . (11) is a logic control circuit for sampling pulse generation connected to the comparator (10), which is formed by using a microcomputer or the like, and has a head switching pulse signal at the RFSW input terminal (12), that is, the RFSW signal, and Based on the clock signal of the operation standard of R-DAT, the reproduction of the synchronizing signal is digitally detected from the output signal of the comparator (10), and the pilot signal from the adjacent two tracks is detected by the timer calculation at each detection. The crosstalk timing is calculated, and the sampling pulses SP1 and SP2 are formed and output at the timing.

Reference numeral (13) is a gate circuit connected to the control circuit (11), and based on the RFSW signal of the input terminal (12) and the reproduction mode signal, sampling pulses are generated during the long time reproduction.
SP1 and SP2 are selectively supplied to the sample hold circuits (5) and (7), respectively.

Each circuit except the gate circuit (13) is a conventional R-DA
It consists of a T tracking control block.

During reproduction, the reproduction signals of both heads are input to the amplifier (2) via the input terminal (1), and the amplifier (2)
The reproduced signal amplified by is input to each of the filter (3) and the equalizer circuit (9).

Further, the filter (3) removes the frequency component of the input reproduced signal higher than the pilot signal, extracts almost only the frequency component of the pilot signal (hereinafter referred to as the pilot component), and the detector (3) detects the detection circuit ( The extracted pilot component is output to 4).

Then, by the envelope detection of the detection circuit (4),
The envelope detection signal of the pilot component included in the reproduction signal is output from the detection circuit (4) to the sample hold circuit (5) and the subtractor (6).

On the other hand, the reproduction signal waveform-equalized by the equalizer circuit (9) is input to the comparator (10), and the reproduction signal is binarized and digitized by the comparator (10).

At this time, based on waveform equalization and digitization, the output signal of the comparator (10) becomes a digital signal of a signal component having a large level change, that is, a signal component of a trace track having the same azimuth as the head included in the reproduction signal. .

Then, the digital signal output from the comparator (10) is input to the control circuit (11), and the sync pattern detection of the control circuit (11) detects the comparator (10) at the interval of the operation reference clock signal of the frequency 9.408 MHz. ) Is sampled, the inversion period of the digital signal of the comparator (10) is detected, and the inversion period is the frequency f ₂ (= 52
2.67KHz) or f ₃ (= 784.00KHz) cycle, the sync detection pulse is formed.

In addition, the RFSW is determined by the track discrimination of the control circuit (11).
The next trace track that switches based on the signal is
For example, the four-track complete track (A ₁ ) in Figure 8,
(B ₁ ), (A ₂ ), or (B ₂ ) is predicted, and the synchronization detection pulse formed in each one cycle of the synchronization signal by the reproduction of the synchronization signal is counted, Based on the result of the counting, the trace track is established during the reproduction of the sync signal.

Furthermore, based on the confirmation of the trace track, the sampling pulse is generated by the control circuit (11), so that the sync signal of each of the first and second ATF areas (ATF1) and (ATF2) of the trace track shown in FIGS. Sampling pulse at the timing when the pilot signal crosstalks from each of the two adjacent tracks based on the reproduction detection.
SP1 and SP2 are formed and output to the gate circuit (13).

That is, as is apparent from FIG. 8, the length of the synchronization signal in the area (ATF1) is 0.5τ in the tracks (A ₁ ), (B ₁ ), (A ₂ ), and (B ₂ ) for one cycle. Become a track (A
_{In 1} ) and (B ₁ ), the length of the sync signal in the area (ATF2) is also
0.5τ, the length of the sync signal in the area (ATF1) is 1τ
In the tracks (A ₂ ) and (B ₂ ) that become, the length of the synchronization signal in the area (ATF2) is also 1τ.

When the reproduction of the synchronization signal is started and the synchronization detection pulse is formed, the output signal of the detection circuit (4) is
One of the two adjacent tracks, that is, the trailing side traced after the trace track, that is, the track on the right side of each track in FIG. 8 (hereinafter referred to as R track) becomes a cross-talked pilot component, and the sync component of the sync detection pulse is generated. When about 2 τ has elapsed from the start of input, the output signal of the detection circuit (4) shows the other side of the two adjacent tracks, that is, the preceding side traced before the trace track, that is, the track on the left side of each track in FIG. (Hereinafter, referred to as L track), a cross component becomes a pilot component.

Therefore, the control circuit (11) immediately forms the sampling pulse SP1 when the sync detection pulse starts to be formed and starts counting the sync detection pulse, and the count value of the sync detection pulse is based on the prediction of the trace track. Based on the judgment whether the count value of 0.5 τ or 1 τ has been reached, it is discriminated whether the sync signal is reproduced or not, and the trace track is confirmed. When 2 τ has elapsed from the start of counting the sync detection pulse, , Form a sampling pulse SP2.

Therefore, both heads are in the area (ATF1),
(ATF2) When tracing each, control circuit (1
Sampling pulses SP1 and SP2 are output from 1) to the gate circuit (13) at the timing when the pilot components of two adjacent tracks crosstalk.

For example, when tracing tiger stick is first of 8 view tracks (A _2), as shown in FIG. 2 (a), the trace of the track first 1ATF area (A ₂₎ (ATF1),
As the reproduction signal of the trace track (A ₂ ), the pilot signal is reproduced for 2τ and then the synchronization signal of f ₂ is reproduced for 1τ at an interval of 1τ. At this time, the R, L track (B ₂ ),
The pilot signal from (B ₁ ) is the trace track (A ₂ )
Crosstalk occurs during and after the synchronization signal is reproduced, and the trace track (A ₂ ) pilot signal and
When the pilot components that crosstalk from the R, L tracks (B ₂ ) and (B ₁ ) are Pm and Pr, Pl, respectively, the output signal of the detection circuit (4) changes as shown in FIG.
Sampling pulses SP1 and SP2 are output at the respective timings (c) and (d) in FIG.

Then, during reproduction in the standard mode, that is, during reproduction in which the tape running speed and the drum rotating speed are the same standard running speed and standard rotating speed as during recording, the gate circuit (13) directly outputs the sampling pulses SP1 to SP2 to the sample hold circuit. Output to (5) and (7) respectively.

At this time, based on the sampling pulse SP1 that has passed through the gate circuit (13), the sample hold circuit (5)
The pilot component Pr cross-talked from the R track is sampled and held for each head trace.

Furthermore, the subtractor (6) subtracts the output signal of the sample hold circuit (5) from the output signal of the detection circuit (4), outputs the sampling pulse SP2, and outputs the output signal of the detection circuit (4) from the L track. When the cross-talked pilot component Pl is obtained, the output signal of the subtractor (6) is a signal proportional to the level difference of the cross-talked pilot component from two adjacent tracks.

The sample-hold circuit (7) samples and holds the output signal of the subtractor (6) based on the sampling pulse SP2 that has passed through the gate circuit (13). Therefore, the output terminal (8) is output from the sample-hold circuit (7). The tracking error signal output to the drive circuit of the capstan motor via the signal becomes an S-characteristic signal proportional to the level difference of the pilot component cross-talked from two adjacent tracks, and the tape running phase is based on the signal. Controlled.

By the way, when playing in standard mode,
Since the drum rotation speed is the same as during recording, the tracing direction of both heads is along the track direction.

Then, based on the control of the tape running phase, the tape running phase is variably controlled so that the centers of both heads coincide with the track center, the levels of the pilot components cross-talked from two adjacent tracks become equal, and the tracking error signal is generated. When becomes 0, the centers of both heads coincide with the track center, and at this time, the on-track state is complete.

That is, during reproduction in the standard mode, the tracking error signal changes as shown by the solid line in FIG. 3 in accordance with the tracking deviation, and both heads are pulled into a perfect on-track state based on the error signal.

On the other hand, when playing in the long time mode, since the tape is played back by the double scan method, the tape running speed is set to the specified running speed in the long time mode, which is the same as that during recording, and the drum rotation speed is twice as fast as during recording. It is set to a speed, that is, twice the specified rotation speed in the long time mode.

At this time, the trace end position on the tape advances in the advancing direction (8th
The left side of the figure is slightly shifted, and as shown in Figs. 4 and 5, the trace directions of both heads are slightly offset from the track direction, and the trace positions of both heads are 1/2 of those in the standard mode. Both heads double-skip the tape as it only moves a little.

In FIGS. 4 and 5, (A) and (B) show tracks formed in order, and (Ha ₁ ), (Hb ₁ ), (Ha
₂ ), (Hb ₂ ), (Ha ₃ ) show sequential head traces, and (Ha ₁ ), (Hb ₂ ), (Ha ₃ ) show azimuth head traces of track (A), (Hb ₁ ). , (Hb ₂ ) are traces of the azimuth head of the track (B).

Then, even during the reproduction in the long time mode, the tape reproduction is performed without switching the characteristics of the electromagnetic conversion system such as the head and the rotary transformer, the characteristics of the amplifier (2) and the equalizer circuit (9), and FIG. Since the tracking control block of this is activated and the drum rotation speed is higher than that at the time of recording, electromagnetic conversion, amplification of the amplifier (2), and waveform equalization of the equalizer circuit (9) are almost the same as those at the time of reproduction in the standard mode. Is performed with the characteristics of.

Further, the RFSW signal of the input terminal (12) shown in FIG. 6 (a), that is, the RFSW signal of the same cycle as that in the normal mode reproduction based on the drum rotation speed is input to the control circuit (11). The trace head switches every time the signal level is inverted, that is, every half rotation of the rotating drum.

Then, the level inversion of the RFSW signal and the switching of the trace head become the same as during the reproduction in the standard mode, and the control circuit (11) operates in the same way as during the reproduction in the standard mode. When the trace track sync signal is reproduced, the control circuit (11) forms and outputs sampling pulses SP1 and SP2 at the respective timings of FIGS. 6 (b) and 6 (c).

In addition, since the tape is wound around the rotating drum by 90 ° and travels, the time during which both heads play the tape is
1 / front of high level and low level of RFSW signal
The period of 2 is the period corresponding to 90 ° rotation of the rotating drum.

By the way, by playing the double-skiyan tape,
The head trace position is approximately the track width W for each trace.
1/2 of the standard mode, that is, about 1/2 of the time of playback in the standard mode, and if the azimuth track different from the trace head becomes the trace track, the sync signal cannot be detected, so the control circuit ( The sampling pulses SP1 and SP2 are not output from 11).

When the head traces are as shown in FIGS. 4 and 5, in the continuous four head traces, two traces are necessarily traces that are almost on-track to the same azimuth track.

That is, in the case of FIG. 4, four consecutive traces (Ha
₁ ), (Hb ₁ ), (Ha ₂ ), and (Hb ₂ ), the first and second two traces (Ha ₁ ), (Hb ₁ ) shown by the solid line are tracks (A), (B) of the same azimuth. ) Each trace is almost on-track, and the remaining 3rd and 4th traces (Ha ₂ ) and (Hb ₂ ) shown in broken lines are different azimuth tracks (B) and (A), respectively. .

In the case of FIG. 5, four consecutive traces (H
a ₁ ), (Hb ₁ ), (Ha ₂ ), and (Hb ₂ ), the first and fourth two traces (Ha ₁ ), (Hb ₂ ) shown by the solid lines are the same azimuth track (A), ( B) Each trace is almost on-track, and the remaining second and third parts shown in broken lines
In the second two traces (Hb ₁ ) and (Ha ₂ ), different azimuth tracks are trace tracks.

And in the case of FIG. 4, also in the next four traces (Ha ₃ ) of the head race (Hb ₂ ), ..., the first trace (Ha ₃ ) and the second trace are almost on-track to the same azimuth track. Similarly, in the case of FIG. 5, in the four traces following the head trace (Hb ₂ ), the first and fourth traces are almost on-track to the same azimuth track.

Therefore, in both cases of FIG. 4 and FIG. 5, two consecutive traces become traces that are almost on track to the same azimuth track, and the next two consecutive traces become traces of different azimuth track. .

If tracking control is performed at the trace positions shown in FIGS. 4 and 5, the tracks (A) and (B) are always connected to the head of the same azimuth based on the traces shown in FIGS. 4 and 5. Traced almost on track.

By the way, if the heads of the azimuths of the tracks (A) and (B) are designated HA and HB, the lead-in to the trace position in FIG. 4 is carried out every two consecutive traces in the order of head HA and HB. , Sampling pulses SP1 and SP2 to the sample and hold circuits (5) and (7) during two traces by HB
Prohibits the supply of, pilot component (Pr), by stopping the sampling of the (Pl), the trace (Ha _1), (H
In b ₁ ), moving the tracking position to the left and right respectively is repeated in a short cycle every 4 traces.
It can be done automatically.

In addition, pulling in to the trace position in Fig.
For every two consecutive traces in the order of B and HA, the next head HB, H
Between the two traces of A, the sample and hold circuit (5),
By prohibiting the supply of sampling pulses SP1 and SP2 to (7) and stopping the sampling of the pilot components (Pr) and (Pl), the tracking position is set to the right when tracing (Ha ₁ ) and (Hb ₂ ). , Moving to the left side is repeated automatically in a short cycle every 4 traces.

Therefore, in the long-time mode reproduction, the gate circuit (13) forms an inhibition gate signal having a length of 2 traces for every 2 traces based on the RFSW signal of the input terminal (12), and based on the gate signal. The sampling pulses SP1 and SP2 output from the control circuit (11) are intermittently supplied to the sample hold circuits (5) and (7), respectively.

That is, when pulling in to the tracking position shown in FIG. 4, the gate circuit (13) causes four consecutive traces (Ha
₁ ), (Hb ₁ ), (Ha ₂ ), and (Hb ₂ ) of 2 traces (Ha ₂ ), (Hb ₂ ), sampling pulses SP1, SP
The output of 2 is prohibited, and the sampling pulses SP1 and SP2 are output from the gate circuit (13) at the two trace cycles shown in FIGS. 6 (d) and 6 (e). At this time, the sample hold circuit (5), (7) is 2 traces (Ha ₁ ), (H
During the next two traces (Ha ₂ ) and (Hb ₂ ) after b ₁ ), sampling of the input signal is stopped.

Then, based on the deviation between the track direction and the trace direction, the AT on the end side of each of the traces (Ha ₁ ) and (Hb ₁ )
Since the F area (ATF2) is shifted to the left side (leading side) from the ATF area (ATF1) on the start end side, the tracking error signals output from the ATF areas (ATF1) and (ATF2) of the trace (Ha ₁ ) are The characteristics shown in the broken lines α1 and α2 in FIG. 3 change, and the ATF area (ATF1) of the trace (Hb ₁ ),
The tracking error signal output by each (ATF2) changes according to the characteristics shown by broken lines β1 and β2 in FIG.

At this time, if the broken lines α1 and α2 are moved in the vertical axis direction (the axis of the error signal level) so that the error signal levels of the tracking deviations 0 of the broken lines α1 and α2 become substantially the same negative level, the broken lines α1 and α2 Becomes almost equal to the broken lines β1 and β2, respectively, so that the combined characteristic of the broken lines α1, α2, β1 and β2 becomes an S-shaped characteristic that passes through the origin of almost no tracking deviation.

Then, by the servo control of the tracking position based on the tracking error signals of the broken lines α1, α2, β1, β2,
The tracking positions of the head HA and HB are pulled to the position of the origin of the previous synthetic characteristics, that is, the tracking position of FIG.

On the other hand, when retracting to the tracking position shown in FIG. 5, the gate circuit (13) causes continuous 4 traces (Ha ₁ ),
2 traces of (Hb ₁ ), (Ha ₂ ), and (Hb ₂ ) (H
b ₁ ), (Ha ₂ ), the output of the sampling pulses SP1, SP2 is prohibited, and in this case as well, the broken lines α1, α2, β1,
By the servo control of the tracking position based on the tracking error signal having the same characteristic as β2, the tracking positions of the heads HA and HB are pulled to the tracking positions of FIG.

Therefore, in the case of the above-described embodiment, by stopping the sampling of the sample hold circuits (5) and (7) for the next two traces for every two consecutive traces,
Both heads HA, H at the tracking position shown in Fig. 4 or 5.
B is tracking controlled, and good reproduction by the double scan method can be performed with a simple configuration in which a gate circuit (13) is added.

By the way, as is clear from FIG. 3, for example, when the control shown in FIG. 4 is performed, the tracking error signal formed by the trace (Ha ₁ ) tries to pull the head Ha into the complete on-track state, and vice versa. , The tracking error signal formed on the trace (Hb ₁ ) tries to pull the head Hb into a perfect on-track state.

Therefore, even if either one of the heads HA and HB becomes jammed and cannot be played back, tracking control is performed based on the tracking error signal so that the head that can be played back is on-track, and relatively good playback is possible. Can be done.

At the beginning and end of each track (A) and (B), ATF
Areas (ATF1) and (ATF2) are provided respectively, and the combined characteristics of the broken lines α1 and β2 and the combined characteristics of the broken lines α2 and β1 in FIG. 3 are the same as the combined characteristics of the broken lines α1, α2, β1 and β2.
Since it has an S-shaped characteristic that passes through almost the origin, based on drop-out etc., the ATs of the tracks (A) and (B) are opposite to each other.
F area, eg ATF area of track (A) (ATF2)
Even if the sync signal of the ATF area (ATF1) of the track (B) cannot be detected, the remaining ATF areas of the tracks (A) and (B), that is, the ATF of the track (A), respectively.
Area (ATF1) and track (B) ATF area (ATF2)
Based on the detection of the sync signal of, the heads Ha and Hb are controlled to the tracking positions shown in FIG. 4 or 5, and good reproduction can be performed.

In addition, in the above-described embodiment, the explanation is given by applying to the R-DAT.
-It can also be applied to the playback method of a rotary head type tape recorder that controls playback tracking by an area-divided ATF of a format different from DAT. In this case, the number, position, and long-time mode of the ATF area of each track are used. Needless to say, the specified traveling speed, specified rotation speed, etc. may differ from those of the embodiment.

〔The invention's effect〕

As described above, according to the reproducing method of the rotary head type tape recorder of the present invention, during the reproduction in the long time mode, the rotating drum is pulled up to the standard rotation speed which is twice the specified rotation speed in the long time mode, and continuously. The following 2 for every 2 traces
By stopping the sampling of the tracking error signal during the trace, the characteristics of the electromagnetic conversion system, the characteristics of the reproduction circuit system, etc. can be taped by the double scan method without changing from the time of reproduction at the standard running speed and standard rotation speed. It is possible to perform good reproduction by performing tracking control during reproduction on the basis of simple gate processing of the tracking error signal and pulling both heads into an almost on-track state.

[Brief description of drawings]

1 to 6 show an embodiment of the reproducing method of the rotary head type tape recorder of the present invention. FIG. 1 is a block diagram, and FIGS. 2 (a) to 2 (d) are explanations of sampling pulse formation timing. 3 is a characteristic chart of a tracking error signal, FIGS. 4 and 5 are head trace tracing diagrams, and FIGS. 6A to 6E are timing charts for explaining the operation. FIG. 7 and FIG. 8 are explanatory views of the track pattern of the rotary head type digital audio tape recorder and the format of the ATF area. (T) ...... magnetic tape, (ATF1), (ATF2) ...... ATF _{area, (A), (A 1} ), (A 2), (B), (B 0),
(B ₁ ), (B ₂ ) ... track, (1) ... reproduction input terminal, (2) ... reproduction amplifier, (3) ... low pass filter, (4) ... envelope detection circuit, (5) , (7)
...... First and second sample-and-hold circuits, (6) …… Subtractor, (8) …… Control output terminal, (9) …… Reproduction equalizer circuit, (10) …… Comparator, (11) …… Control circuit, (1
2) …… RFSW input terminal, (13) …… gate circuit.

Claims (1)

(57) [Claims] 1. A pair of rotating magnetic heads having mutually opposite azimuths provided 180 degrees apart from each other on the periphery of a rotating drum to helically scan a magnetic tape running around the drum at a constant angle for recording. A track having a width narrower than the gear length of both heads is sequentially formed on the magnetic tape in a guard bandless manner, and at least one sync signal for sampling reference and a pilot signal for tracking are provided at one or more positions of each track for several track periods. An ATF area recorded in a repeating pattern is provided, and at the time of reproduction, the sync signal of the trace track is prepared for detection, and the crosstalk component of the pilot signal from each of the two tracks adjacent to the track is sampled. Form a tracking control signal proportional to the level difference of the crosstalk component. The tape running speed is controlled by the control signal to control the tape running phase by the control signal, and the two heads are tracked. When playing back a magnetic tape recorded in a long-time mode that is 1/2 of the standard rotation speed, set the tape running speed to the specified running speed of 1/2 of the standard running speed in the long-time mode, and The drum rotation speed is set to the standard rotation speed which is twice the specified rotation speed in the long time mode, and the sampling is stopped for the next two traces for every two consecutive traces. How to play a rotating head tape recorder.