JPS623450A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute the complicated retrieving without a fixed head by recording and reproducing the position information of the first information or the second information with a digital signal at the prescribed area of the first part in the first and second parts inclined and provided to the track in the length-wise direction of the magnetic tape. CONSTITUTION:A track 2 is formed inclining to guide tracks 5 and 7 in the length-wise direction of a magnetic tape 1 of the magnetic recording reproducing device. At the track 2, the first part is formed in which the winding angle to the rotating drum corresponds to about 36 deg. and the second part is formed in which the angle corresponds to about 185 deg.. At the area of the first part, a PCM audio signal and a pilot signal TPS for tracking are recorded. At the second part area, an FM audio signal and the TPS signal are recorded. In one side positive direction of the adjoining track 2, the azimuth angle of respective corresponding rotating heads in other angle direction is inclined to about 10 deg., the crosstalk between the tracks 2 is decreased and the complicated retrieving can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus for recording and reproducing information using a rotating magnetic head such as a video tape recorder.

[Summary of the invention]

The present invention forms a first portion and a second portion on a track inclined with respect to the longitudinal direction of a magnetic tape by a one-rotation magnetic head, and forms a first or second portion on the first portion or the second portion. In a magnetic recording/reproducing device for recording or reproducing information, positional information of the first information or the second information is recorded or reproduced as a digital signal in a predetermined area of the first part, thereby making the fixed head specially This makes it possible to search for the minute position of the first information or the second information without having to provide the first information or the second information.

[Conventional technology]

2. Description of the Related Art In magnetic recording and reproducing devices such as video tape recorders, a tape counter is sometimes used to search for a predetermined recording or reproducing position. However, searching using a tape counter has the drawback of lacking accuracy. Therefore, a control signal (CTL signal) for tracking control, which is generally a 30 Hz rectangular wave signal obtained from a pulse generator of a rotating drum, is sometimes used for the search. Since the CTL signal only uses the timing of one edge for tracking, a signal with a changed duty can be used as a cue signal (cue signal or index signal) for position search. be.

However, such a search method using CTL signals requires a fixed head placed corresponding to the track on which the CTL signal is recorded and an additional circuit around it. Like a tape recorder, each track is provided with a tracking pilot signal f, , f, , f, , f (each, for example, 6.5 f, ,
7.5ft, 10.5fw, 9.5f++ (f
m is the frequency of the horizontal synchronizing signal)), and cannot basically be used in devices that do not require a CTL signal. If adopted, it would be necessary to provide a fixed head, etc., which is basically unnecessary, just for searching, and multiple indexes corresponding to one tilt (video) track would be recorded on one cue track. Case 1: For example, a special recording method such as time division is required,
The equipment becomes complex and expensive. Furthermore, since the cue track is located near the edge of the magnetic tape, it has the disadvantage that it is easily damaged by the tape guide.

Therefore, the present applicant proposed that the inclined track of an 8om video tape recorder is formed with a first part where the first information is recorded and a second part where the second information is recorded, and The portion further includes a portion a where a clock signal is recorded;
The part where data such as PC:M audio signals is recorded, the margin part C for after recording,
It is divided into a video overlap part d where the video signal of the immediately preceding field is continuously recorded, and it was previously proposed to record an index signal in this part C or part d (Japanese Patent Application No. 60-2464). No., patent application 1986-2725
No. 6, etc.).

[Problem that the invention seeks to solve]

However, such a conventional proposal records and reproduces the position information of the first or second information as an index signal (analog signal) of a predetermined frequency. It was difficult to search for. Another disadvantage is that it is not possible to increase the number of types of index signals, and only a simple search is possible.

[Means for solving problems]

FIG. 1 shows a block diagram when the magnetic recording/reproducing apparatus of the present invention is applied to an 8-inch video tape recorder.

In the figure, reference numeral 11 denotes a rotating drum, into which a rotating magnetic head (not shown) for recording or reproducing is mounted. 1
2 is a motor that rotates the rotating drum 11. 13 is a pulse generator that outputs a signal with a frequency and phase corresponding to the rotation of the rotating drum 11, and its output is sent to the servo circuit 1.
4 is supplied. The servo circuit 14 outputs a rotation control signal to the motor 12, and also outputs a head switching signal (H8WP signal) for switching a plurality of rotating magnetic heads. This head switching signal is supplied to various circuits via a variable delay circuit 15 provided as necessary. Reference numerals 16 and 17 denote a reproduction amplifier and a recording amplifier that amplify the signal output from the rotating magnetic head or the signal supplied to the rotating magnetic head. A demodulation circuit 18 extracts a clock signal from the output signal of the reproduction amplifier 16 and demodulates a data signal using the clock signal.

Reference numeral 19 denotes a PCM circuit that converts the input analog audio signal into PCM and outputs it as a digital signal to the recording amplifier 17, and also converts the digital data signal input from the demodulation circuit 18 from D/A and outputs it as an analog signal.

Reference numeral 20 denotes a position information circuit, which detects position information from the data signal and clock signal input from the demodulation circuit 18, and a control device 21 consisting of a microcomputer or the like.
The device information consisting of is modulated and output to the recording amplifier 17.

A position detection circuit 22 detects a predetermined position in the reproduced signal from the output signal of the PCM circuit 19.

[Operation] The operation will be explained with reference to FIGS. 2 to 5. Signals to be recorded, such as video signals, FM audio signals, and tracking pilot signals, are supplied to the recording amplifier 17 from a video circuit, an FM audio circuit, a tracking circuit, etc. (not shown). Also, the audio signal is PCM
Circuit 19. The signal is A/D converted, modulated using a predetermined method (for example, pi-phase), and supplied to the recording amplifier 17. These signals are supplied from the recording amplifier 17 to the rotating magnetic head and recorded on the magnetic tape.

During this time, the servo circuit 14 compares the signal from the pulse generator 13 with the reference signal, and controls the motor 12 in response to the error signal.
control the rotation of On the other hand, during reproduction, the reproduction signal from the rotating magnetic head is amplified by the reproduction amplifier 16 and supplied to the video circuit, FM audio circuit, tracking circuit, etc. Further, a reproduction signal from the reproduction amplifier 16 is supplied to a demodulation circuit 18.

There, the clock signal and data signal are demodulated.

This data signal is D/A converted at PCM@path 19,
Output as an analog audio signal.

FIG. 3 shows how signals are recorded on the magnetic tape in this manner. That is, tracks 2 are formed on the magnetic tape 1, which are inclined with respect to its longitudinal direction. For convenience, the track 2 has a first part corresponding to a winding angle of about 36 degrees of the magnetic tape 1 with respect to the rotating drum 1, and a first part corresponding to a winding angle of about 185 degrees.
and a second part corresponding to the degree of PCM.
Audio signal and tracking pilot signal (TP
In the latter case, an FM video signal, an FM audio signal, and a tracking pilot signal can be multiplexed and recorded. The azimuth angle of the corresponding rotating magnetic head is inclined by about 10 degrees in the positive direction on one side of the adjacent tracks 2 and in the negative direction on the other side, so that crosstalk from the adjacent tracks is reduced. It has become. An audio track 4 of a cap R is formed near one edge 3, and a normal analog audio signal can be recorded by a fixed head as required. A cue track having a width C is formed near the other edge 3, and a cue signal is recorded by a fixed head as necessary. 5
and 7 are guard tracks provided between the information recording track and the control signal recording track.

Table 1 FIG. 4 shows one track 2 enlarged. That is, the first part further includes a part a where a clock signal is recorded, a part where data such as a PCM audio signal is recorded, and a margin part C for after-recording.
and a video overlap section d where the video signal of the immediately previous field is continuously recorded.

The end position of the portion d is the switching position of the rotary magnetic head, and the vertical synchronizing signal is located at a position separated by a distance e from there.

The length of each of these parts is 1, for example in the case of NTSC system, 525 lines, 6o field system and 1
For example, 625 lines as in the PAL system,
In the 5o field system, the settings are as shown in Table 1.

FIG. 5 shows a case where a plurality of parts corresponding to the first part are formed in the second part (part d can be considered to be included in the second part, but for convenience, it is included in the first part). In other words, the length of the first part is an integral multiple of approximately five times the length of the second part, and five parts corresponding to the first part are formed in the second part. For example, a PCM audio signal, for example, is recorded in each of six parts in total, consisting of parts a to d. In this case, the portion d may be a mere guard area, and no signal may be recorded therein.

Next, an explanation will be given of the operation when recording a position information signal of information recorded in the first portion or the second portion. In the present invention, the position information signal is transmitted to a predetermined area of the first portion of the track 2 (for example, the margin area C or the overlap area d).
), but in the following explanation it is assumed that it is recorded in part C.

First, when no PCM audio signal is recorded in the second portion, the following procedure is performed. That is, the servo circuit 14 obtains a predetermined delay time as necessary by counting predetermined clock pulses, for example, from the output of the pulse generator 13 corresponding to the rotation of the rotary drum 11, and outputs the head switching signal (HSWP). (Figure 2 (a)
)), this signal is supplied to various circuits via a variable delay circuit 15 (the variable delay circuit 15 is not necessarily necessary if the track configuration is as shown in FIGS. 3 and 4). When a predetermined time has elapsed since the generation of the head switching signal (for example, in the case of the NTSC system, the position information circuit 20
．． 5) When H has elapsed), that is, at the timing when the recording area of the position information signal of part C arrives (second
(d)), along with a recording pulse of a predetermined width (for example, 2.5H), a recording signal (
The recording amplifier 17 modulates the position information) using a predetermined method.
Output to. The control device 21 outputs a data signal corresponding to area i as a recording signal, and also outputs a clock signal corresponding to area i as a preamble of area i. In the same way that area k is used as a postamble (margin part) for area i, area j following area i is used as a postamble (margin part for recording position information) for area i (second Figure (d)), if the data is recorded in area i, for example, four blocks bO to b in the case of NTSC system.
3 (In the case of the PAL system, by increasing the number of blocks to, for example, 5 blocks by the amount of the lower field rate, the transmission rate can be made approximately the same as in the case of the NTSC system). Figure 2 (e)),
Each block has, for example, a 3-bit synchronization signal (sy) and an 8-bit synchronization signal (sy).
It can be a bit block address (ad) and data WO to WB consisting of 12 8-bits (1 byte) (FIG. 2(f)). If 4 bytes out of 12 bytes of data are used for cyclic code for block error detection, parity for error correction, etc., 32 bytes (8x4) for one area i, 1920 bytes (32x4) per second. 60) location information can be recorded. The length of each region can be selected as shown in Table 2, for example. The recording area falls within the margin portion C when the area k is the minimum and the area j is the maximum, but when the area C is also the maximum, a part of it will cover the overlap portion d. However, as described above, in the overlap area d, the video signal of the previous field is continuously recorded or is used as a guard area with virtually no signal, so a part of the recording area overlaps. Even if it falls under part d, there is almost no problem in practice.

For example, when a PCM audio signal is recorded on all of one track 2 as shown in FIG.

6 recording areas of one track 2 (part htxtj)
variable delay circuit 1 so that recording pulses are generated at
5 is provided.

Table 2 In this case as well, the basic timing is the same as in the cases shown in Figures 3 and 4, so the variable delay circuit 1
There is no need to provide any special circuit other than 5.

Erasing the position information signal is performed by a rotating video head or a rotating erasing head. Alternatively, data that has no meaning as position information may be newly recorded.

In the above operation, recording pulses are generated using the head switching signal as a timing reference, so there is no difference between the recording position error on the magnetic tape during recording and playback, or the difference between the information recorded in the first part and the second part. The timing may be shifted due to a time axis error with the information recorded in the section (the allowable range of time axis error during recording or playback is ±1.5
H, it is unavoidable that there will be a deviation of ±3H in the worst case. So when playing the first part, at least there P
When a CM audio signal is recorded, the position detection circuit 22 detects 1 from the demodulated signal of the PCM audio signal.
For example, the start point of portion C or the end point of portion C can be detected using a signal obtained by decoding a synchronization signal indicating the start of data, an arbitrarily determined specific data block address, etc. as a timing reference. (b)) A signal indicating the recording position of the position information signal may be generated in synchronization with this detection signal. Therefore, in this case, position information circuit 2
0 uses the output of the position detection circuit 22 when a PCM audio signal is recorded, and the output of the variable delay circuit 15 when no PCM audio signal is recorded, as a timing reference for recording pulses (erase pulses). ) are generated respectively.

On the other hand, during a search or normal reproduction, the position information circuit 20 inputs the signal to the demodulation circuit 18 via the one-rotation magnetic head and the reproduction amplifier 16, and extracts the position information signal recorded in area i from the signal demodulated there. It is read and temporarily stored in the memory corresponding to the address (ad), and after error detection and correction, reliable position information is output to the control device 21.

The control device 21 compares the designated and input position information with the position information from the position information circuit 20 and designates it.

Search the input location information. At this time, in order to detect the position information signal, the position information signal is detected in the vicinity of the position information signal recording area htltj of the margin portion C. As a signal for gate-extracting only the reproduced signal, a pulse with a wide width that sufficiently includes fluctuations during tape running may be generated and used in synchronization with the output of the 1-position detection circuit 22.

In addition to recording or erasing a position information signal when recording a video signal or audio signal with a rotating magnetic head, it is also possible to record or erase a position information signal when reproducing a video signal or an audio signal with a single rotation magnetic head. It can also be done. In the latter case, the leakage of the position information recording signal will affect the weak playback signal output, so it is better to mute the video signal and FM audio signal appropriately when supplying the position information signal. Modulation method (bi-phase), transmission rate (5, sMb
/s) etc. are the same as the PCM circuit 19, and the PCM circuit 19
Many parts can be shared with the PCM circuit 19 by, for example, being operated by receiving a main clock from the PCM circuit 19. Furthermore, location information includes address information for searches.

It can include time information, character information, etc. In addition, if ID information including position information is supplied to the PCM circuit 19 via the control device 21 and recorded in the partial area, the position information is not newly generated and is recorded in the partial area. The ID information may be transferred as is to area i. Although it is not possible to rewrite or erase ID information recorded in a partial area independently of other information (PCM audio information) recorded in a partial area, the information recorded in area i can be used as a video or It can be recorded, erased, and rewritten independently of audio information.

〔effect〕

As described above, the present invention forms a first portion and a second portion on a track inclined with respect to the longitudinal direction of a magnetic tape by a one-rotation magnetic head, and a first portion is formed on the first portion or the second portion.
Or, in a magnetic recording and reproducing device for recording or reproducing the second information, the position information of the first information or the second information is recorded or reproduced as a digital signal in a predetermined area of the first part. , a fixed head is specially provided - (1
child.

Not only can the position of the first information or the second information be searched minutely, but also many types of position information can be recorded and reproduced, making complex searches possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the magnetic recording/reproducing apparatus of the present invention, and FIG.
The figure is a timing chart, FIG. 3 is a plan view of an 8m video tape, and FIGS. 4 and 5 are enlarged plan views of its tracks. 1... Magnetic tape 2... Track 3... Edge 4... Audio track 5.7... Guard track 6... Cue track 11... Rotating drum 12... Motor 13...・
Pulse generator 14... Servo circuit 15... Variable delay circuit 16... Playback amplifier 17... Recording amplifier
18... Demodulation circuit 19... PCM circuit 20... Position information circuit 21... Control device 22... Position detection circuit and above

Claims (1)

[Claims] Forming a first portion and a second portion on a track inclined with respect to the longitudinal direction of a magnetic tape by a rotating magnetic head,
In a magnetic recording and reproducing device that records or reproduces first or second information in the first part or the second part, the first information or the second information is recorded in a predetermined area of the first part.
What is claimed is: 1. A magnetic recording and reproducing device that records or reproduces positional information of information as a digital signal.