JPH0438085A - Video system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a video system, and relates to a tape-shaped recording medium in which a large number of tracks are formed, each recording a video signal h for one field. The present invention relates to a video system comprised of devices that perform recording and playback in a specific period shorter than one field period.

[Prior Art] A home-use vertical scan video table recorder (VTR) is a device for recording and reproducing one field of video signals on each track of a tape-shaped recording medium. I will explain about it.

Generally, a so-called rotating 2-helical helical scan type is known as a home VTR. Figure 7 (A), (B
) is a diagram showing a general head arrangement of this type of VTR. In FIGS. 7(A) and (B), 1 is a magnetic tape, 2
Reference numerals a and 2b designate tape kites for wrapping the tape 1 around the outer periphery of the rotating drum 3 over an angular range of 180° or more.

The rotating heads are attached to the rotating drum 3 with a phase difference of 180° from each other, and as shown in the figure, they are attached at the same height in the direction of the rotation axis, and have different azimuth angles. As is well known, the head HAHB records and reproduces one field's worth of video signals while rotating 180 degrees.

In this type of VTR, the length of a track on which one field of video signals is recorded is predetermined in the standard. Therefore, the diameter of the rotary tram 3 is inevitably determined accordingly. Therefore, reducing the diameter of the tram 3 has hindered the miniaturization of the VTR.

Therefore, the following VTRs have been proposed as VTRs whose drum diameter can be reduced. Figures 8 (A) and (B) show a conventional VTR using a small diameter tram.
FIG. In the figure, Ha and Hb are rotary heads having different azimuth angles, and rotate once during one field period of the video signal. Rotating head Ha,
The Hb's are arranged to rotate close to each other with a small phase difference of θ°, and are mounted at the same height in the rotational axis direction as shown in the figure.

The tapes 1 are wound around the tram 3 over an angular range of 300° or more, and the rotary heads HaHb each have an angle of 300° or more.
The video camera records one field while rotating. That is, one field of video (No. 2 will be recorded for a shorter period than the original one field period of the video signal).

Therefore, if we assume that the video recorded by this type of VTR is NTSC (No. 2), then the normal NTS
Cie, that is, vertical scanning frequency (f v ) h':
60Hz, horizontal scanning frequency (fh) is 15.75kt
Not tz signal, fv is 60Hz, fh is 18.9
(15,75
“It’s impossible.”

In other words, the video 4Zs recorded by this type of VTR must be a normal television signal time-axis compressed to 5/6 in units of fields or a signal obtained from a dedicated video camera.

The video camera dedicated to the above two scans a screen with an aspect ratio of 9:10 (indicated by the dotted line Y in Figure 9), and scans a screen with an aspect ratio of 3.4 (indicated by the solid line X in Figure 9). It is output as a valid screen within the 5/6 field period.

The heads Ha and Hb shown in FIGS. 8(A) and 8(B) are 5.
Since it is possible to form one track within a /6 filtration period, it is possible to record one field of video signal on one track, and the head arrangement shown in FIGS. 7(A) and (B) It becomes possible to record video signals in a format similar to that of a VTR. That is, a VT with a head arrangement as shown in FIG.
By recording a video signal using R as described above, the drum diameter can be reduced to 315 mm compared to a VTR equipped with a head shown in FIG.

Further, the time axis expansion of the reproduced video signal by 6775 fields can be carried out by the VTR having the head arrangement shown in FIG. 8 in the same way as the VTR having the head arrangement shown in FIG. 7.

[Problems to be Solved and Attempted by the Invention] By the way, when recording and reproducing standard television signals in a VTR using a small drum as shown in FIG.
Since the video signal is time-axis compressed to 5/6 field by field, it is necessary to expand the time-axis by one field and return it to the standard television signal format when playing back.

Generally, when configuring a VTR using such a small drum, it is conceivable to use it as a camera-integrated VTR. This camera-integrated VTR is often used outdoors, so power consumption must be kept to a minimum.

However, since the above-described time axis expansion circuit for each field normally uses a digital memory, it consumes a large amount of power and generates heat. Therefore, when used as the above-mentioned camera-integrated VTR, the presence of this time axis expansion circuit causes restrictions on usage time and usage opportunities, which is not preferable. It is an object of the present invention to provide a video system that reduces the size and weight of a portable recording device that has a camera integrated therein, and that does not impose restrictions on its usage time, usage opportunities, etc.

[Means for Solving the Problems] For this purpose, the video system of the present invention provides a video system in which a video signal for one field is time-axis compressed into a specific period shorter than the one field period for each one field period. a recording device that integrally comprises an imaging means for outputting a signal, and a recording means for recording the video signal from the imaging means on a tape-shaped recording medium with a rotary head that rotates once in the one field period; From a tape-shaped recording medium formed of a large number of tracks recorded with a video signal of 1 minute,
Reproducing means for reproducing the video signal by tracing each track in the specific period using a rotary head that rotates once per field period, and selectively inputting the output signal of the reproducing means and the video signal from the imaging means. and time axis expansion means for expanding the video signal of the specific period into the one field period.

[Function] By configuring as described above, the time axis expansion means is provided only in the playback device, and the recording device can be made smaller and lighter, and the power consumption is reduced, making it easier to use when the recording device is used as a portable device. , there are no restrictions on usage opportunities or usage time.

[Example] Hereinafter, examples of the ability basket of the present invention will be explained in detail.

FIG. 1 is a block diagram showing a schematic configuration of a video system as an embodiment of the present invention, FIG. 2 is a diagram showing the overall appearance of the system in FIG. 1, and FIGS. 2 is a diagram showing head configurations of a reproducing side VTR and a recording side VTR of the system of FIG. 1. FIG.

The head configuration of the reproducing side and recording side VTR in the system of this embodiment is different from the head configurations shown in FIGS. 9(A) and 9(B) in that the heads Ha and Hb are one track pitch (ITP) in the direction of the rotation axis. The difference is that the heads Ha and Hb are shifted and placed on an electrostrictive element 61 as an actuator for displacing them in the direction of the rotation axis.

In FIGS. 1 and 2, P indicates a reproduction side VTR 1R and a recording side VTR.

40 and 41 are magnetic tapes, and the recording format of these tapes is the same as that of the VTR having the head configuration shown in FIG. 7 described above.

First, the normal playback operation of the playback VTR shown in FIGS. 1 and 2 will be explained. When a normal reproduction command is issued from the operating section 34, the system controller 35 controls the servo circuit 17 to control the capstan motor 42, and the capstan C transports the tape 1 one track at a time during one field period. On the other hand, the system controller 35
The servo circuit 17 controls the tram motor 43 so that the tram D rotates once per field period. At this point, the heads Ha and Hb each trace each track one track in sequence, or during one field period in which the head Ha traces the track Ta at the azimuth angle corresponding to the head Ha, the head This means that the head Hb is tracing the track Tb with the azimuth angle corresponding to Hb, and during this period the heads Ha and Hb can compare the reproduced signals. On the other hand, in the next one field period following this one field period, the head Ha
or track Tb, and trace head Hb or track Tb.
A must be traced, and it is only possible to compare the reproduced signals.

FIG. 4 is a timing chart for explaining the operation of each part of the system of this embodiment. In the figure, A+, B+
, A2 . . . indicate a video signal for one field. In the VTR in the dubbing system of this embodiment, the video signal originally shown in FIG. 4(a) is converted into the video signal shown in FIG. 4(c).
, (d). Incidentally, in the VTR having the head arrangement shown in FIG. 8 described above, a reproduced signal as shown in FIG. 4(b) can be obtained.

The reproduced signal from the head Hb is delayed by one field period in the one-field delay circuit 18, and is input to the switch 11 together with the reproduced signal from the head Ha. The switch 11 is connected to the head Ha side during one field period in which heads Ha, Hb or No. 13 can be reproduced, and the switch 11 is connected to the head Ha side, and
During the field period, it is connected to the delay circuit 18 side. As a result, the output signal of the switch 11 is as shown in FIG. 4(b).
As shown in the figure, the signal of each field becomes a signal whose time axis is compressed to 5/6.

FIG. 5 is a diagram for explaining signals reproduced by the VTR of system b of this embodiment. FIG. 5(a) shows the spectrum arrangement of the signal recorded and reproduced by the VTR with the head arrangement shown in FIG. 7, and FIG. 5(b) shows the spectrum of the signal recorded and reproduced by the VTR in the system of this embodiment. Show placement. In the figure, Y indicates an FM modulated luminance signal, A indicates an FM modulated audio signal, and C indicates a low frequency converted chroma signal.As is clear from FIG. 5, in this embodiment, the frequency of the signal output from the switch 11 is , the reproduction signal of the VTR with the head arrangement shown in FIG. 6], and the operating frequency of the reproduction video signal processing circuit 12 is 12 times that of the VTR with the head arrangement shown in FIG.

The reproduced video signal processing circuit 12 frequency-converts the reproduced video signal obtained by FM demodulating the FM modulated luminance signal in the signal inputted from the switch 11 and the chroma signal converted to the low frequency band to the original band. A reproduced video signal obtained by mixing the obtained reproduced chroma signal is output. The synchronization separation circuit 16 divides the synchronization signal in the reproduced video signal and supplies it to the search circuit 17.
Tram motor 43 and capstan motor 42 as described above
It is used as a reference signal for control.

In order to faithfully trace each track of the head Ha,)(b), the search circuit 17 controls the capstan motor 42 so that the output amplitude of the switch 11 is maximized.This tracking is well known. However, since it is not directly related to the present invention, detailed explanation will be omitted.

Since this reproduced video signal is a signal in which the signal of each field is time-axis compressed to 5/6, it cannot be used when being supplied to an external monitor or the like. The switch 81 is connected to the A side by the system controller 35 when the VTR on the playback side is in the normal playback mode, and the playback video signal output from the playback video signal processing circuit 12 is passed through the A#6 terminal of the switch 81. The signal is supplied to the time axis expansion circuit 13. In the circuit 13, the signal of each field of the reproduced video signal is time-axis expanded to 615, and is displayed on a normal monitor 83.
and is output from terminal +4.

Note that since the audio signal is not directly related to the present invention, a description thereof will be omitted in this specification.

Next, the normal recording operation of the recording side VTR in FIGS. 1 and 2 will be explained. The IA fIIll VTR in the system of this embodiment is a camera-integrated VT.
R is assumed, and has the above-mentioned dedicated video camera (overscan camera) 31.

The head configuration is the same as that of the reproducing VTR, but ``'' is added for distinction. The camera 31 is the fourth camera as described above.
A video signal as shown in FIG. 3(b) is converted and supplied to a recording video signal processing circuit 23 and a synchronization separation circuit 24.

The servo circuit 26 controls the capstan motor 44 using the signal supplied from the system controller 37 according to the operation of the operation unit 36 and the synchronization signal separated by the synchronization separation circuit 24, and controls the capstan motor 44 for one field period using the capstan C. The tape 41 is conveyed one trunk per time, and the tram motor 45 is operated to transport the tape 41 for one trunk per field period.
Control the rotating rod.

The recording video signal processing circuit 23 performs FM modulation on the luminance signal and converts the subcarrier frequency of the chroma signal to a low frequency, as shown in FIG.
A signal as shown in b) is provided to the switch 25. The switch 25 alternately switches to the delay circuit 19 side for each field.
Connected to the head Hb' side. As a result, the head H
The signals supplied to a' Hb are shown in Fig. 3 (c) and (d
). The heads Ha and Hb are shifted from each other by one trunk pitch in the direction of the rotation axis, and the head Ha'
The tape 41 is traced slightly ahead of the head Hb'. As a result, a 2°C track is formed simultaneously by the heads Ha' and Hb' once every two degrees, and as a result, it is possible to record in the same way as the VTR whose head arrangement is shown in Figures 7 and 8. becomes.

The signal output from the camera 31 is also scanned from the top edge to the bottom edge of the monitor screen in one field period cycle and within 5/6 field periods, and is sent to a dedicated monitor (overview) with a horizontal scanning frequency of 5715 as usual. scan monitor)
49, and the recording state is monitored. This monitor 49 is used as an electronic fuse inter in a camera-integrated VTR, as shown in the second [x].

When it is desired to output the video signal shot by the overscan video camera 31 of the recording VTR to the outside, the recording VTR and the reproducing VTR are connected by a connection 85 as shown in FIG. Reference numeral 82 denotes a coupling detection circuit for detecting whether or not this connection court is connected to the reproduction side VTR, and the detection output of the coupling detection circuit 82 is also supplied to the system controller 35. The system controller 35 connects the switch 81 to the B side when the reproduction side VTR is performing reproduction and the detection circuit 82 detects whether the connection coat 85 is connected. At this time, the output of the overscan video camera 31 is supplied to the time axis expansion circuit via the terminals 21c, +5c, and the B terminal of the switch 81, and is supplied to the monitor 83 and output from the output terminal 14.

Next, the operation during dubbing using the above-mentioned reproduction side and recording side VTR will be explained.

When the playback side ~'TR and the recording side VTR are connected as described above through the connection coat 85, the output terminal 15 of the playback side VTR is connected.
a, 15b are connected to input terminals 21a, 21b of the recording side VTR. In this state, playback 11jjl V T
When the dubbing mode is designated by the operation section 34 of R and the operation section 36 of the recording side VTR, the servo circuit 17.26 controls the capstan motor 42.44,
, c' transports the tape 40, 41 for two trunks per field period, and the tram motor 444
5 is controlled 11 times so that trams D and D' rotate once per field period.

As a result, the playback blades FHa and Hb each race one tape 40+ every two trunks. The servo circuit 17 performs tracking control to the point at which the output of the switch 11 becomes maximum at the point where the reproducing head Ha,
Hb will race only on tracks Ta and Tb, respectively.

However, since the transport speed of the tape 4o is different from that of the normal recording speed described above, the inability of the heads Ha and Hb to trace parallel to the track will be explained using FIG. In the 6th and 1st, the bean corresponds to the running of (7) 7-T/40 during the regeneration of the tile, and i) is the reproducing head Ha.
, Hb, and io is a 6-hector of these. During dubbing, the vector corresponding to the running of the tape 40 is 2iT, and the resultant vector is τ. In order to match this vector τ with τ0, in this embodiment, the vector τ. A motion corresponding to this is given by an electrostrictive element 61 made of a highmorph plate.

That is, during the 5/6 field period in which the heads Ha and Hb are tracing the tape 40, the electrostrictive element 61 continuously shifts the heads Ha and Hb by one track in the direction of the rotation axis, and the remaining 1/6 During the field period, the resetting operation is repeated for each field. This operation is
given by 7. As a result, the heads Ha, Hb
traces in a direction parallel to the track, and the tracks Ta and Tb are accurately traced by the above-mentioned tracking control.

In Fig. 3(B), 61 is a bimorph plate, and 62
is a terminal to which a control signal from the servo circuit 17 is applied;
63 is a sensor such as a strain cage. This sensor 6
Reference numeral 3 denotes a device capable of detecting the absolute position of the heads Ha, Hb in the rotational axis direction, and is provided to accurately determine the positions of the heads Ha, Hb during normal recording and reproduction. The output of the sensor 63 will be fed back to the servo circuit 17.

Figures 4(e) and 4(f) show the reproduced signals of the six outputs ``Ha'' and ``Hb'' during this dubbing.
b.

The recording side VTR receives the fourth section (e), (
A signal as shown in f) is received from the terminal 21a21b and sent to the heads Ha' and Hb' via the recording amplifiers 47a and 47b.
supply to. Heads Ha' and Hb' are electrostrictive elements 6
1' gives the same displacement as that of the reproducing heads Ha and Hb, and this is controlled by the servo circuit 26.

As a result, the heads Ha' and Hb' trace on the tape 41 in the same direction as during normal recording.
This operation of simultaneously recording two fields of video signals on adjacent tracks with different azimuth angles is performed every one field period.

As a result, dubbing can be performed at a speed of 2 times faster than the normal recording/reproducing operation.

In this dubbing mode, the system controller 35 of the playback Φl VTR fixes the switch 11 to the A side, and sends only the output of the head Ha to the playback video signal processing circuit 1.
Combined with 2. Here, the reproduction signal of head) (a is the fourth
The signal is as shown in FIG. 3(e), and if this signal is fed directly to the reproduced video signal processing circuit 12, the same reproduced video signal as in the case of commercial reproduction will be obtained. However, if an interlaced video signal is assumed here, only one field of each frame will be played back, so every other field is delayed by a horizontal scanning period to prevent skew from occurring. It is desirable to prevent this.

Depending on the configuration of the above-mentioned embodiment, the recording side VTR
Since there is no need to provide a time axis expansion circuit in the camera, it is possible to make the camera-integrated VTR more compact and quantitative, and to minimize power consumption. In addition, the chance of heat generation due to the operation of these circuits is minimized, and the usage time is shortened when using a VTR with a small drum as shown in Figure 1 as a camera-integrated VTR. , there will be no problem of decreased usage opportunities. Furthermore, by combining a reproduction side VTR and a recording side VTR as shown in Figure 1, it is possible to use a VTR with a small tram diameter, without increasing the number of heads, and with simple dubbing terminals and amplifiers. By adding a circuit, it becomes possible to perform high-speed dubbing at twice the normal speed.

In this specification, the system is constructed assuming a VTR that records and reproduces one track per rotation, or a video signal recording and reproducing device that generally records and reproduces the video signal of each field once in a period shorter than one field period. Any system using the present invention can be similarly effective by applying the present invention, and the embodiments can be modified as appropriate within the scope of the claims.

[Effects of the Invention] As explained above, the video system of the present invention uses a small drum, making the recording device more compact and lightweight, and minimizing its power consumption and heat generation. This eliminates restrictions on usage time, usage opportunities, etc. when this recording device is used as a portable device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a dubbing system as an embodiment of the present invention, FIG. 2 is a diagram showing the overall appearance of the system in FIG. 1, and FIGS. Figure 4 is a timing chart showing the signal processing timing of each part in the system shown in Figure 1, and Figure 5 explains the video signals handled by the system shown in Figure 1. Figure 6 is a diagram for explaining head trace trajectories during normal recording and playback and dubbing in the VTR of the system shown in Figure 1. Figures 7 (A) and (B) are diagrams for explaining conventional general A diagram showing the head arrangement of a VTR. Figures 8 (A) and (B) show a conventional VT using a small drum.
FIG. 9 is a diagram for explaining a video camera used exclusively in a VTR whose head arrangement is shown in FIG. 8. In the figure, Ha, Hb, Ha', Hb' are rotating heads, c, c' are capstans, D, D' are drums, 13 is a time axis expansion circuit, 14 is a video output terminal,
31 is an overscan video camera, 36 is an operation unit,
35 and 37 are system controllers, 40 and 41 are magnetic tapes, 49 is an overscan monitor,
81 is a switch, 82 is a coupling detection circuit, and 85 is a connection coat.

Claims (3)

[Claims] (1) Imaging means for outputting a video signal in which a video signal for one field is time-axis compressed into a specific period shorter than the one field period for each one field period, and a video signal from the imaging means for outputting a video signal for the one field period. A recording device integrally comprising a recording means for recording on a tape-shaped recording medium with a rotary head that rotates once at a speed, and a tape-shaped recording medium having a number of tracks each recording one field of video signals. From 1 above
Reproducing means for reproducing the video signal by tracing each track in the specific period using a rotary head that rotates once per field period, and selectively inputting the output signal of the reproducing means and the video signal from the imaging means. and a time axis expansion means for time axis expansion of the video signal of the specific period into the one field period. (2) It further comprises a detection means for detecting electrical coupling between the reproducing device and the recording device, and an input signal to the time axis expansion means is selected according to a detection output of the detection means. A video system according to claim (1). (3) Furthermore, in order to supply the reproduction signal of the reproduction means to the recording means, the dubbing means electrically couples the reproduction means and the recording means, and when dubbing by the dubbing means, the time axis is expanded. A video system according to claim 1, characterized in that the output signal of said reproduction means is selected as an input signal to said means.