JPS6150209A - Recording and reproducing method of pilot signal - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a head with position control in its vertical revolving direction in a recording mode, by specifically controlling the record/reproduction timing of pilot signals with continuous four tracks defined as a cycle. CONSTITUTION:An area 20 equivalent to a period of 3G is set for a pilot signal f5 between a PCM recording area 1 and a video signal area 2. The start timing of the area 2 shown by an alternate long and short dash line 21 is defined as a standard S. The reproduction and recording periods P4 and R4 are started with timing S-G and S-2G respectively on a track T4. For a track T1, the reproduction and recording periods P1 and R1 are started with timing S-3/2G and S-5/2G respectively. For a track T2, the start timing of the recording and reproduction periods R2 and P2 are set at S-3G and S-2G respectively. Furthermore, the reproduction and recording periods P3 and R3 are started with timing S-5/2G and S-3/2G respectively. The wave lines show the periods when crosstalk are extracted and are equal to 2alphaH respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a method for recording and reproducing pilot signals in a video cheap recorder (VTR) having a function of rotating and vertically displacing a recording and reproducing head.

(B) Prior Art In the standard called 8mm video, a tracking system is specified as an option in which a recording/reproducing (R/P) head can be rotated and displaced in the vertical direction using a bimorph or the like. With this tracking method, R/
In order to control the rotational vertical position of the P head, a pilot signal 8 (usually called f5, 230
A method using a method with a frequency of KHz] is used.

In other words, if the R/P hent t', which is 180 degrees opposed to the rotary sill and is supported by a bimorph or the like, is removed,
A pilot signal f5 is recorded and reproduced during a predetermined period (3) between the PCM area (1) and the video area (2).

In the figure, arrow A indicates the tape running direction, and arrow Bti indicates the rotation direction of the head. Further, this pattern shows a case where the tape running speed is 14.345 layers/sec, and αH is IH. Truck (al), (al),
(λ5) is a track recorded by one head (sensation), and (bl), (bl), (b5) are tracks recorded by the other head (
El)K was recorded.

The pilot signal f5 is being recorded by the R/E' head (a).
, is recorded for an IH period from a predetermined position from the bottom end of the tape.

Immediately after that, for 1H period, the R/P head is in the reproducing state, and the crosstalk of the pilot signal f5 of the track (for example, (b+)) previously recorded by the head φ;)K is reproduced. . The crosstalk signal obtained from this track (al) VC and the stored track (b)
+) are compared to control the position of the R/P head in the rotational direction (arrow C in the figure). This is a part that can be extracted.

Now, in order to enable longer recording times in a VTR, a method is usually adopted in which the tape running speed during recording is reduced. At this time, αH also decreases, and for example, the tape running speed is reduced to 1/2 of the above case (7,1725 m/5
ec), (EH will also be 0.5H. FIG. 8 shows the case where the tape running speed is set to 1/2.

At this time, the track pitch is 1/2, but
The 1H period is the same as in Figure @7, and the Talostalk signal can be derived only from the pi portion. That is, the period during which the Talostalk signal can be collected is shorter than in the case of FIG. 7.

Furthermore, when the R/P head is suddenly switched from the recording state to the playback state, the playback signal can only be output a little later than the start of the playback state, so the period during which the crosstalk signal can be obtained is different. As a result, it becomes difficult to derive a control signal for controlling the position of the R/P head in the rotational direction without error.

Taking this point into consideration, Japanese Patent Application Laid-Open No. 139328/1983 provides a record of a pilot signal f5 for a predetermined period unrelated to αH recorded in the immediately preceding track, as shown in Figure 4 or Figure 113 in the publication. A technique is disclosed in which the R/P head is placed in a reproducing state for a short period of time during a scanning period adjacent to a section.

However, even if the R/P head enters the playback state, a crosstalk signal is immediately generated (c) Problems to be Solved by the Invention As described above, in the prior art, the crosstalk signal is generated immediately after the R/P head enters the playback state. Therefore, there is a risk that a losstalk signal cannot be obtained.
There was a risk that the position control of the P head would malfunction.

In the present invention, the recording and reproducing timing of the pilot signal 'j)fs is controlled using consecutive four-tricks and two-tsks as one cycle. The recording period and the playback period are equal and are denoted by G. Further, let S be the upper limit timing of the recording/reproducing area of the pilot signal f5. In the first track (
Pilot signal 9 for period G from the timing of S-mutual G)
r f s is recorded, and the R/P head is put into a reproduction state for a period G from the timing of (S-ΣG). The pilot signal f5 is recorded on the second track from the timing of Vi (S-5G), and the reproduction state starts from the timing of (S-2G). In the sixth track, the R/P head enters the playback state from <s-'-c), and (S--z
The pilot signal f5 is recorded for a period G from the timing G). In the fourth track, the pilot signal f5 is recorded for a period G from the timing (S-2G), and the pilot signal f5 is recorded from the timing (S-2G).
The playback state starts from the timing of S-G). From then on, the first
~The same thing as the fourth track is repeated. Further, the recording interval and the reproduction period G are changed according to the tape running speed, and G=K·αH (K is a constant).

(E) Effect If the recording period and the reproduction period G (=K・αH), the period T during which the Talostalk signal can be extracted is K≦2.
When 6...(1) T=-zG-
It is represented by αH, and by changing the time period for K)2, it is possible to set the period during which the Talostalk signal can be extracted to a desired value.

(f) Example First, the principle will be explained based on the drawings. FIG. 5 is a diagram showing the arrangement of the recording period (8) and the reproduction period ψ) of the pilot signal f5, and numbers such as (Rn) indicate that they correspond to the n-th track.

1. Also, in this arrangement, the combination of the first to fourth tracks is 81 cycles. When arranged as shown in FIG. 5, since recording and reproduction are reversed on the sixth track, the period in which the Talostalk signal can be collected is always equal to the recording period and the reproduction period G.

Next, the relationship between period G and αH can be considered as shown in FIG. That is, the pilot signal '1jfs is the period (R
The line (1υ) connecting the terminal end 1101 of 4) and the period (R2)
It is thought that the starting end of (the line connecting 121 (placed between 13 and the length G) corresponds to αHK. Therefore, the period G is equal to 2αH (K = 2). On the other hand, the pilot signal ) of the area related to f5 becomes equal to the 6G period.Then, based on FIG. 1, the timing in the actual tape pattern is determined. In the figure, arrow A indicates the tape running direction, and arrow B indicates the head scanning direction. @Bin (1) is an area for P-0M recording, area (2) is a 9A area for video signals, and between them there is a pilot (g) chain acid (corresponding to the SG period) for 8-R5. )■ is set.

The start timing (S) of the video area (2) indicated by the dashed line C11l is considered as a reference. (However, (S) is defined as the bottom edge of the tape (timing from the prisoner.)
For track 4 (T4), the end of the playback period (R4) is (S
), the playback period (R4) is (S-G
), and similarly, the recording period (R4) starts at the timing (S-2G).

The first track (T1) is identical to the fourth track (T4), and the recording period (R1) starts at the timing of (S and G).

In the second track (T2), the start timing of the recording period (R2) coincides with the start of the 15-head pilot region corresponding to the time width 3G, so the recording period and the playback period (
The start timing of R2) (R2) is (S-3G), respectively.
(S-2G). In the 6th track (T5), '@
Recording period (Rs) depending on the relationship with 2 tracks (T2)
is started at the timing of (S-ΣG).

The part #i indicated by the broken line indicates the period T during which the Talostalk signal can be extracted, as in FIG. 7, and in the case of FIG. 1, the period T is equal to 2αH.

Next, start the recording period of the pilot signal on each track,
The timing of the start of the playback period is the same as in the first case, but the relationship between the period G and αH is different, that is, G=K・
Consider the case where αH becomes 2.

FIG. 2 shows the case where Δ=1.5 (<2).

In this case, the period T indicated by the dotted line is, for example, the reproduction period (Pl
) is determined by subtracting the start timing of the G period of the immediately preceding track N from the end timing of the track N. That is, 'r=f (S-HG)+G-αH1-(S-2G) =-G-αH(=1.25H)...(1)
becomes.

In the 9υ5 figure, =2. ．． 5 (>2). In this case, R4) rack (T4) recording period (
R4) Playback period (P+) of the first track (T1) from the end
) Just subtract the starting end. That is, =1G+αH('
L25)-1) (2) Both equations are equal when K=2.

FIG. 4 shows the configuration of the gc position for realizing FIGS. 1 to 6. To achieve this, V at the timings shown in Figures 1 to 6.
What is necessary is to create a recording gate signal and a reproduction gate signal that set the TR to the pilot signal f5 recording condition abrupt and reproduction condition irregular. In FIG. 4, 6 is an input terminal for an RF switching pulse, which is a reference signal indicating the rotational phase of the rotary head.
1) is a gate signal generation circuit that creates each gate signal based on the RF switching pulse, and 130 is a gate signal generation circuit that creates each gate signal based on the RF switching pulse.
These are first and second changeover switches that select the output and sequentially derive a reproduction gate signal (b) and a recording gate signal (to).

Since the start edge (S) of the video area is defined by the timing from the rising and falling edges of the RF switching pulse, the timing of each gate signal is also defined by the amount of delay from the rising and falling edges of the RF switching pulse. A gate signal with a width G can be easily created. That is,
The signal from the terminal (3Ll) is delayed from the edge of the RF switching pulse, rises at the timing of (S4G), and becomes H.
A gate signal equal to the V bevel G period is obtained. Similarly, the rising timing from the terminal (31b) is (S-2
G) timing, from terminal (31C) to h (s-4G)
A gate signal is derived from the terminal (S1d) at a timing of (SG), and from a terminal (31e) at a timing of Vi (S-3G). A predetermined delay from the RF switching pulse can be easily achieved using monomultis.

@1 and the second changeover switch oaten are sequentially changed over based on RF switching pulses, and terminals (P+) and (R+) are selected while recording the first track.

Next, consider the tape running speed shown in FIGS. 7 and 8. In the case of FIG. 8, αH=0.5H. At this time, in order to set T=IH, G is 1H from equation (2).
It only needs to be equal to the period (therefore, = 2). Therefore, even if αH becomes small due to a decrease in the tape running speed, a sufficient period can be provided during which the crosstalk signal can be extracted.

Also, in the case of αH=IH shown in FIG.
= 1) To set i, use formula (1), G = 3-H
All you have to do is set it to 44. ■ is equal to the 4H period. Therefore, in both the case of Figure J7 and the case of Figure 8, sufficient areas M and cA are provided in front of the video area, and G of the gate signal generation circuit is controlled by an appropriate control signal depending on the tape running speed. The configuration may be such that the value of is changed.

(G) Effects of the Invention As described above, according to the present invention, even if the tape running speed decreases and αH becomes small, it is possible to set a sufficiently long period in which the Talostalk signal can be collected, so that recording is possible. This can prevent malfunctions in position control in the vertical direction when the head rotates.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are diagrams showing the track pattern of the present invention, Figure 4 is a block diagram of the gate signal generation circuit, and Figures 5 and 6 are diagrams for explaining the present invention in detail. It is an explanatory diagram. Figures 7 and 8 are diagrams showing track patterns in the prior art. Track n+1f to track n+4...
(TI) (T2) (Ts) (T4), Viroft Sign 8 recording period... (R1) (R2) (R5)
(R4), Pilot signal regeneration period...(P+)(
P2) (Ps) (P4).

Claims (1)

[Claims] (1) When recording signals on a tape using multiple heads that can be displaced in the rotational vertical direction, when the scanning timing at the reference position on the tape is (S) and the pilot signal recording period is G. , in the n+1st (n is an integer) track, G starts from the timing (S-5/2G).
Record the pilot signal for a period of G, and record the nth period for a subsequent G period.
The head forming the +1st track is set to a reproduction state, and on the n+2nd track, the pilot signal is recorded for a period of G from the timing (S-3G), and the n+2nd track is formed for the following G period. In the n+3rd track, from the timing (S-3/2G) to the G period, the n+3rd head is in the playback state.
Put the head forming the th track into the playback state,
The pilot signal is recorded for the following G period, and in the n+4th track, the G is recorded from the timing of (S-2G).
Record the pilot signal for a period of G, and record the nth period for a subsequent G period.
+ A pilot signal recording and reproducing method in which the head forming the fourth track is placed in a reproducing state.