JP2650269B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus capable of recording and reproducing a video signal on a tape in a diagonal direction of a tape by a rotating magnetic head. The present invention relates to a magnetic recording / reproducing apparatus suitable for adding a marker signal to a track and searching for a video signal recorded on the track by cue search.

[Summary of the Invention]

According to the present invention, in a helical scan type VTR that records a video signal by a rotating magnetic head, the video signal is recorded, for example, when printing out a video signal recorded on an oblique track of a tape. A marker signal is recorded over an area outside the recording area of the track by a rotary head over several fields, and after searching for the marker signal, a video signal specified by the marker signal is searched and printed out. is there.

[Conventional technology]

A method of recording / reproducing a video signal and an audio signal on an 8 mm video tape by a helical scan method has been standardized as a so-called 8 mm video and has already been commercialized.

FIG. 6 shows an example of such a rotary head device for 8 mm video, and FIG. 7 shows the tape format.

In these figures, H _A and H _B denote rotary heads for recording and reproduction, 1 is a rotary drum, 2 is wound around the rotary drum 1 in the range of 180 ° + α, A magnetic tape running in the direction.

The two rotary heads H _A, H _B is constituted as azimuth angle of the magnetic gap are different from each other, 180 to each other
It is attached so as to slightly protrude from the rotary drum 1 at an angular interval of ゜.

The arrows in frame frequency (30H _Z) of the video signal
It is rotating in the direction of 3H.

Therefore, as shown in FIG. 7, tracks 4A and 4B having different azimuths are alternately formed in the magnetic tape 2 in the oblique direction of the recording tracks of the magnetic tape 2 formed by such a rotary head device.

Usually, a video signal is recorded in an area AV corresponding to the 180 ° angle of the tracks 4A and 4B, and an area AP having an α angle (= 36 °) is recorded.
Is PCM (Puilse Code M)
odulation) signals can be sequentially recorded for each field.

(Note that the audio signal is 8mm video rotary heads H _A and frequency-modulated audio signal not limited to the above-mentioned regions AP, and supplies the H _B, can also be recorded to be superimposed on the area AV of the video signal. As described above, in the recording / reproducing method of 8 mm video, a function for recording / reproducing an audio signal by the rotary heads H _A and H _B is added, so that recording / reproducing of an extremely high quality audio signal is performed. Playback can be performed.

By the way, when the track format of the 8 mm video as described above is described in more detail, the signal arrangement is as shown in FIG.

In other words, from the area where the rotary head is in contact with the tape 2 on one recording track, first, a 5-degree head angle is formed as the rush portion 11, and the latter half of the rush portion 11 is 2.06 degrees (for 3H of the video signal). During this period, the preamble portion 12 is a portion of a clock line synchronized with PCM data.

Subsequent to the preamble section 12, a PCM data section 13 for converting the time-axis-compressed audio signal into PCM data and recording
Provided over 6.32 degrees. And then this PCM
A period of 2.06 degrees (3H) following the data section 13 is a postamble section 14, and a subsequent 2.62 degrees is a VP guard section 15 indicating a boundary between a video signal and a PCM data section.

The recording area 16 of the video signal includes the VP guard section 15.
The video signal for one field is recorded over 180 degrees as described above, and a pilot signal for tracking is superimposed on this portion at the same time.

Finally, a separation portion 17 of about 5 degrees is provided.

PCM data is a binary signal, is recommended to be recorded is FM-modulated for example portion of a logic "1" the frequency 5.8MH _Z signal, the signal of the logic portion of the "0" 2.9MH _Z . Then, the preamble section 12 and the postamble section 14
Is filled with data "1".

By the way, according to the invention proposed by the applicant earlier, such a normal playback mode of 8 mm video, or multi-PCM
At the time of reproduction in the mode, an index signal is recorded in, for example, the postamble section 14 in the track format so that a predetermined recording track can be searched for, and a desired track is read by reading the index signal. Has been proposed. (Problems to be Solved by the Invention) By the way, in the above-described 8 mm video recording method, as described above, in the mode in which an audio signal is recorded as PCM data simultaneously with a video signal, as described above. An index signal is inserted into the postamble section 14, and cue search and cueing can be performed using this index signal.
Some simple 8mm video VTRs that do not have a PCM recording function are also sold as products.
Since an 8mm video VTR originally does not have a fixed head, it is not possible to search for a recorded video signal, and for example, when printing out a predetermined video signal by a video printer, the time required to search for a desired video signal is reduced. There was a problem of becoming long.

[Means for solving the problem]

The present invention has been made in view of such a problem, and for example, a video track formed in an oblique direction, such as V
A portion corresponding to the P card is detected by a counting circuit which counts a clock signal based on, for example, a vertical synchronizing signal of a recorded video signal, and a marker of a predetermined format is added to the portion corresponding to the VP guard; The portion can be recorded over several tracks.

[Action]

Even in the case of a simple 8 mm VTR, the angle at which the magnetic tape is wound around the rotary drum is usually set to be slightly larger than 180 °, and the VP guard of the track of the 8 mm recording format formed in the oblique direction is used. A part of the part 15 becomes a head entry part, and this part can be used as a recording area.

Therefore, when the rotary head passes through the recording area during recording, a mark for identifying a desired recording area track can be added by inputting a predetermined marker signal from the rotary head. The cue of the marked video signal can be performed.

〔Example〕

FIG. 1 shows a recording format on an 8 mm tape showing an embodiment of the present invention. A plurality of tracks T are sequentially formed diagonally on a magnetic tape 10 by two rotating magnetic heads. In the first half, a track area of about 30 ° is a PCM signal area, and a video signal area (Video) is provided in a second half of about 180 ° via a VP guard for about 3.8H.

In the case of the magnetic recording / reproducing apparatus of the present invention, this V
The marker signal M is recorded on a predetermined track in the area of the -P guard, and is read out.

FIG. 2 is an enlarged view of this part, which shows a rush part 11 of the head, a preamble part 12 of the PCM signal, a PCM data part 13,
In the area of the VP guard section 15 after the postamble section 14, a marker area 15A for about 0.5H is provided. In the marker area 15A, in order to search this recording track,
For example, a marker signal M of 2.95 MH is recorded.

This marker signal M is recorded up to the track T _N following the cueing track T ₀ shown in FIG. 1 and continuing for t (about 10) seconds.

The PCM data section 13 and the VP guard section 15 for separating the video signal recording area 16 are provided with an 8 mm VT having no PCM recording function.
In R, it corresponds to the head entry portion, but if a 0.5H marker area 15A is formed at a position 0.8H from the front end of the video signal recording area 16, the tape path is adjusted within the reference range. In this case, it is sufficiently possible to record or reproduce a signal in this area by the circuit head.

In addition, even in the case of an 8 mm VTR having a PCM recording function, it goes without saying that a signal can be recorded in the marker area 15A and reproduced.

Therefore, if the marker signal M is recorded over several tracks at the above-described positions, the marker signal M can be detected in the cue search mode as described later, and after the marker signal M is confirmed. performs rewind operation of the tape, after slightly passed the track T _0, when the normal reproduction state, can be switched from the position of the track T _0, which marks the normal playback operation, if necessary, the You can print out forwards playback screen of the track T ₀ in the memory of the printer connected to the VTR.

As the marker signal M, for example, an alternating number VP of 2.95 MH
It was to be recorded over several tracks during the 0.5H guard region 15, for example, the arbitrary track T ₄ in the mark period t as shown in FIG. 1 2.95 / 2 MH _Z marker signal M
If you recorded _2, after performing the beginning, also allow cue the track in the mark period t by further detecting the marker signal M _2.

Further, in the case of the present invention, the marker signal M is encoded by a digital signal and recorded.

FIG. 3 is a waveform diagram showing an example of encoding the marker signal M. First, in the marker signal area 15A of the 0.5H period,
Start bit signal D _S is placed at the beginning, next to the mode bit signal D _M is provided that. This mode bit signal D _M A indicates the type of data in the code signal D ₀ to D ₃ of the subsequent four words, the code signal D ₀ to D ₃ of 8-bit configuration or the time code, or address code Identify the printout number.

D _C is the error correction code, D _E denotes an end bit signal.

When a signal coded as the marker signal M is recorded in this way, this marker signal can be used as an index signal for various purposes, like an 8 mm VTR capable of PCM recording.

Next, an embodiment for reproducing (recording) the marker signal will be described with reference to the block diagram of FIG.

Reference numeral 20 denotes a rotating drum having two rotating magnetic heads H _A and H _B , 21 denotes a recording / reproducing changeover switch, 22A and 22B denote amplifiers for outputting a reproduction signal, and 22C and 22D denote recording signals by the rotating magnetic head. head H _a, the amplifier supplies the H _B, 23 denotes a switch circuit for switching the rotary head H _a, the H _B by the switching pulse, eg PCM signal reproduced in the PCM recording is possible models as shown by a dotted line It is switched so that it is input to the audio signal processing circuit 24.

For models without the PCM recording function, the rotating magnetic head H _A ,
Reproduced signal is continuous H _B is input to the video signal processing circuit 25, the audio signal being FM modulated is input to separated audio signal processing circuit 24.

26 is a gate circuit closed by the pulse generator 32 described later during the period of the marker signal area, 27 is a demodulation circuit, 28 is a signal detection circuit, and 29 is a control signal corresponding to various operation modes of 8 mm VTR. A control unit (CPU) 30 is a system controller.

Reference numeral 31 denotes a counter which counts a clock signal locked to the horizontal synchronization signal being reproduced or recorded, and this counter is reset to 0 when the vertical synchronization signal VD is input. When the counter 31 reaches a predetermined count value, a signal having a pulse width of approximately 0.5 H is output from the pulse generation circuit 32, and the gate circuits 26 and 33 are closed.

A marker generator 34 outputs a marker signal to be recorded.

Reference numeral 35 denotes a switching pulse generation circuit that detects the rotational phase reference signal PG of the rotary drum 20 and forms an open / close switching pulse for the switch circuit 23.

The operation of detecting a desired marker signal by cue search and performing cueing by the circuit of the embodiment of the present invention will be described below with reference to FIG.

The magnetic recording / reproducing apparatus of the present invention provides the
It is characterized in that the marker area 15A of the reproduction signal output from A, 22 is introduced into the gate circuit 26.

The count value of the counter 31 that counts the horizontal synchronizing signal PH of the video signal being reproduced (the horizontal synchronizing signal is a continuous signal by the PLL circuit) becomes N, for example. It is closed for approximately 0.5H by the output SG of the pulse generator 32 driven by the output at the time.

Meanwhile, the counter 31 is also reset to 0 by the vertical synchronization signal VD of the video signal, and counts the vertical synchronization signal PH based on this point. Therefore, the number of horizontal synchronization signals for one field + α (α is almost The number of horizontal synchronizing signals in the end period from the head entry section 11 to the postamble section 14 in FIG.
When the gate circuit 26 is closed with the count value N (corresponding to the number corresponding to the number N), the reproduced output when the rotary head is scanning the marker signal area 15A just passes through the gate circuit 26.

Therefore, when the marker signal M is included in the output signal passing through the gate circuit 26, the signal detected by the demodulation circuit 27 and digitized by the detection intermediary circuit 28 is input to the control unit 29.

When the cue search command is input, the control unit 29 stops the tape running from the time when the marker signal M is detected, and then switches the 8 mm VTR to the rewind mode,
After passing the first track (T ₀ ) where the marker signal M is recorded as described above, the mode is switched to the normal reproduction mode, and the track on which the first marker signal M is recorded is detected.

At this point, for example, a still reproduction state is set, and an operation is performed to output a video signal of a desired track.

Further, the track to which the marker signal M is added can be designated as an editing point, and may be output to a printer to obtain a hard copy.

When recording a marker signal during recording, similarly, the gate circuit 33 is closed only for a period designated by the counter 31 and the pulse generator 32, and the signal output from the marker signal signal generator 3 is applied to the marker signal area 15A of the track. Will be recorded.

In this embodiment, the vertical synchronization signal is used as the counting reference of the counter 31, but the PG signal of the rotating drum may be used to specify the marker signal recording area on the tape.

〔The invention's effect〕

As described above, the magnetic recording and reproducing apparatus of the present invention
In an apparatus for recording and reproducing a video signal and an audio signal by an analog signal, a counting means for resetting based on vertical synchronization information of a recorded video signal and counting horizontal synchronization information, and a rotating head for recording a track by the counting means. A pulse generation circuit for designating a rush area where the area rushes, wherein the rush area is specified by the pulse generation circuit and is completed by a start bit and an end bit on a track where no video signal is recorded. , By adding a marker signal consisting of a coded digital signal and reproducing it,
Since the desired video signal can be detected in the cue search mode and cueing can be performed, the contents of the recorded information are diversified, and the effect that the control is ensured by the detection of the marker composed of the digital signal is obtained. In particular, there is an advantage that the reproduction function can be improved due to the presence of the marker signal when adopted in a simple 8 mm VTR.

[Brief description of the drawings]

FIG. 1 is a diagram showing a track pattern indicating a marker signal position in the magnetic recording / reproducing apparatus of the present invention, FIG. 2 is an explanatory diagram of a track pattern when a marker area is enlarged, and FIG. 3 is an example of a coded marker signal. A code pattern indicating
FIG. 4 is a block diagram showing an embodiment for designating a marker area according to the present invention, FIG. 5 is an explanatory view of a waveform for forming a gate signal, FIG. 6 is a plan view of a rotary drum of 8 mm VTR,
Fig. 7 shows the track pattern of an 8mm VTR tape, and Fig. 8
FIG. 3 is a diagram showing a signal arrangement of recording tracks in 8 mm video. In the figure, 26 is a gate circuit, 27 is a demodulation circuit, 29 is a control unit, 30
Denotes a system controller, 31 denotes a counter, 32 denotes a pulse generator, and M denotes a marker signal.

Claims (1)

(57) [Claims] 1. A magnetic recording / reproducing apparatus of 8 mm standard equipped with a rotary head for recording only an analog video signal or an analog audio signal on an oblique track of a magnetic tape, wherein a reset is performed based on vertical synchronization information of the video signal. Counting means for counting a predetermined number of horizontal synchronization information; a pulse generating circuit for generating a signal specifying an entry area where the rotary head enters a recording area of a track based on an output of the counting means; Circuit means for recording a marker signal consisting of a digital signal completed and coded with recording information start bits and end bits of the tape over a plurality of fields with respect to the inrush area specified by Cueing control of the reproduced video signal is performed by detecting by search A magnetic recording / reproducing apparatus characterized in that: