JPH06302167A - Magnetic tape recording and/or preproducing device - Google Patents

Abstract

PURPOSE:To provide a magnetic tape recording/reproducing device capable of displaying a tape position even without travelling a tape when a cassette is changed. CONSTITUTION:At the time of loading, a brake is put on a supplying side reel platform 5 and thus, the progress of the loading is made and even after a tape 4 is brought into contact with a control/voice/TC(time code) recording/ reproducing head 21, the tape 4 is slided to the head 21 and when the loading is completed, it is stopped in a condition shown in the figure. The reading circuit (not shown in the figure) of a TC signal is operated at the time of this sliding, the TC signal is read and the tape position, that is, the content of the TC signal, is displayed on a display section (not shown in the figure).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape recording and / or reproducing apparatus, and more particularly to reading and displaying a time code signal thereof.

[0002]

2. Description of the Related Art Commercially available video tape recorders (hereinafter referred to as VTRs) have a time code (hereinafter referred to as TC) recording / reproducing function, which is used to find a position specified scene such as an insert assembly at the time of editing. Used for etc.

The TC signal is usually recorded on a linear track at the end of the tape by a fixed head and is displayed on the display section when the tape is reproduced.

[0004]

[Problems to be Solved by the Invention] However, the conventional VTR
However, since the TC signal is reproduced only when the tape is running, the tape position is not displayed until the tape is run a little when the cassette is replaced.

Therefore, it takes time to know which side the tape is located at, which hinders the speeding up of the editing work in which the tapes are frequently replaced.

The present invention has been made to solve such a problem, and it is an object of the present invention to provide a magnetic tape recording and / or reproducing apparatus capable of displaying the tape position without running the tape when the cassette is replaced. It is intended.

[0007]

To achieve the above object, in the present invention, a TC signal is read and displayed during an operation of pulling a tape from a cassette and winding it around a head drum (during tape loading).

That is, according to the present invention, a magnetic tape recording and / or reproducing apparatus is constructed as shown in (1) below.

(1) A magnetic tape recording and / or reproducing apparatus having a function of reading and displaying a time code signal on a tape, comprising a time code signal reading means,
Magnetic tape recording and / or magnetic tape recording comprising drive means for driving the time code signal reading means during loading and display means for displaying the output of the time code reading means.
Or playback device.

[0010]

With the above arrangement, the time code signal on the tape is read and displayed during the tape loading.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples.
FIG. 1 is a diagram showing a state when the loading of the "VTR" according to the embodiment is completed. FIG. 2 is a diagram showing a state during loading, FIG. 3 is a diagram showing a bit configuration of the TC signal, and FIG.
FIG. 4 is a block diagram of a circuit for reading and displaying a TC signal.

First, the tape path of this embodiment will be described with reference to FIG. In the figure, reference numeral 1 is a cassette, and a tape 4 is wound from a supply reel 2 to a winding reel 3 of the cassette. Numerals 5 and 6 are a supply side reel stand and a take-up side reel stand, which are engaged with both reels 2 and 3 in the cassette 1 when the cassette 1 is loaded on the VTR. The reel stands 5 and 6 are driven by a reel motor (not shown) via an idler.

Reference numeral 7 denotes a rotary drum (also referred to as a head drum) on which a magnetic head is mounted, which is arranged at a predetermined angle with respect to the chassis. Reference numeral 8 is an inclined post that regulates the tape entry direction with respect to the entrance side of the rotary drum 7, and 9 is a vertical guide post that regulates the tape height on the drum entrance side. Further, 10 is an inclined post for defining the tape detaching direction from the drum outlet side and returning the tape 4 in parallel to the chassis, and 11 is a vertical guide post for regulating the tape height on the drum outlet side.

Reference numerals 12 and 16 denote tension posts. During tape running, changes in tape tension on these posts are detected by a Hall element (not shown) as position changes of the posts and the reel motor voltage is controlled to control the tape. The tension is kept constant.

A pinch roller 13 is pressed against the capstan 23 while the tape is running, and the tape 4 is conveyed by the rotation of the capstan 23. 1
4 is a vertical post for opening the tape path to the right, 15
Is a vertical post for determining the tape entry direction into the cassette 1.

In addition, a vertical post 17, an impedance roller 18, a full width erasing head 19, a control / voice / TC erasing head 20, a control / voice / TC recording / reproducing head 21, a control / monitor head 22, and a vertical post 24 are mounted on the chassis. It has been planted and forms a tape path.

Next, the bit configuration of the TC signal will be described with reference to FIG. The TC signal consists of 80 bits from 0 bit to 79 bits, and is 1 for each of the hour, minute and second frames.
User's bit (UB) indicating the 0's place and 1's place
It is composed of 8 areas, synchronization bits, and the like. The bit period is a value obtained by dividing the frame period by 80, and becomes a signal in which the preceding and following frame data are connected.

16 bits from 64 bits to 79 bits are synchronization bits, of which 66 to 77 bits are 12 consecutive "1", and 64 and 65 bits are "0, 0", 78 and 79. The bits become "0, 1", and the advancing direction of the tape is determined by these 4 bits.

Next, the reading and display of the TC signal will be described with reference to FIG. The TC signal read from the tape 4 by the fixed head 21 is input to the clock generation circuit 25, the TC signal is read into the synchronous word shift register 26 in accordance with the clock generated accordingly, and the synchronous portion is synchronized in the synchronous detection circuit 27. (12 consecutive "1" s from 66 bits to 77 bits) are detected.

Further, at the same time as the detection by the sync detection circuit 27, the two bits following the sync part are "0,0" or "0,1".
The FF / FR reading direction signal is given to the data shift register 28, the TC signal is read into the data shift register 28 based on the clock signal, and this data is stored in the buffer register 29.

On the other hand, the clock of the input signal is the counter 30.
, And the timing with the synchronization signal is compared by the comparison circuit 31, and when the data group is correct, the TC signal is output from the buffer shift register 29. Since the output TC signal is serial data consisting of 0 and 1, the serial code conversion circuits 32 and 33 perform time code,
It is converted into parallel data for displaying each user's bit, and is displayed on the display unit 35 through the data output controller 34.

Next, reading of the TC signal at the time of loading will be described. When the cassette 1 is loaded, the posts located inside the cassette opening 1a start moving to wind the tape 4 around the rotary drum 7. At this time, the supply side reel base 5 is braked and the tape 4 is pulled out from the winding side reel 3.

After the tape 4 comes into contact with the control / voice / TC recording / playback head 21 (the state shown in FIG. 2) as the loading progresses, the tape 4 slides with respect to the head 21. The signal reading is started and displayed on the display unit 35 until the loading is completed.

TC is the tape-readable tape sliding length and sliding speed. Regarding the sliding length, since the clock is generated by reading the first frame and the data from the second frame is read, it is necessary to completely read the data for two frames. Needs to have a length to pass through, and in consideration of starting to slide from the middle of the frame, a length of 3 frames is required. In this embodiment,
Since the supply side reel base 5 is loaded with the brake applied, the difference between the tape length pulled out while the tape 4 is in contact with the control / audio / TC recording / playback head 21 and the tape length at the loading end is eliminated. Become the chief
Unless the playback tape feeding speed is extremely fast and the tape length for one frame is long, the length for three frames is sufficiently passed.

Regarding the sliding speed, the minimum sliding speed for reading the signal is determined by the recording frequency of the TC signal. Since the sliding speed increases as the loading speed increases, the loading speed may be set so as to be higher than the minimum sliding speed.

Although the present embodiment is a recording / reproducing apparatus, the present invention is not limited to this and can be similarly implemented in a recording-only or reproduction-only apparatus.

[0027]

As described above, according to the present invention,
By reading and displaying the TC signal during loading, it is possible to immediately grasp the tape position of the cassette just by loading the cassette into the device without running the tape, thus improving the efficiency of editing work etc. Becomes

[Brief description of drawings]

FIG. 1 is a diagram showing a state when loading is completed in an embodiment.

FIG. 2 is a diagram showing a state during loading in the embodiment.

FIG. 3 is a diagram showing a bit configuration of a TC signal.

FIG. 4 is a block diagram of a circuit for reading and displaying a TC signal.

[Explanation of symbols]

 4 Tape 21 Control / Voice / TC recording / playback head 35 Display

Claims (1)

[Claims] 1. A magnetic tape recording and / or reproducing apparatus having a function of reading and displaying a time code signal on a tape, the time code signal reading means and the time code signal reading means being driven during loading. A magnetic tape recording and / or reproducing apparatus comprising a driving means and a display means for displaying the output of the time code reading means.