JPS5919995Y2 - tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape recorder, and particularly to a tape recorder capable of automatically detecting a time code.

One method of synchronizing a video tape recorder (hereinafter referred to as VTR) and an audio tape recorder (hereinafter referred to as ATR) using absolute time is to use a time code.

For example, the time code is the well-known SMPT.
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R3) There are standard ones.

Generally, it is often used for electronic editing of VTR.

This time record is 30 times per second as shown in Figure 3.
With frame One frame is represented by an 80-bit pulse, and can represent up to 99 hours, 59 minutes, 59 seconds, and 29 frames. Of the 80 bits, 32 bits are used as free bits B for the user, and 16 bits are Each word is divided into two parts of 4 bits to indicate the hour, minute, second, and number of the frame, and 4 bits of user bits B are inserted between each part. The 16-bit sync word can be used to identify whether the tape is running in the forward direction or the tape is running in the reverse direction, and the information of the code signal rl, r□ is expressed by the difference in inverted phase. It is threatened with a pie phase signal.

Record such SMPTE code on VTR, ATR,
Since synchronization is achieved using this time code, ATR and VT can be synchronized with frame precision and absolute time (address).
R will never go out of synchronization, and even if it does, A will never go out of synchronization.
The synchronizer is designed to automatically set the same time (address) even when a TR or VTR plays.

However, it was inconvenient because the time code could not be read when the tape was stopped, that is, the time code could not be read at the beginning of a program recorded on an ATR tape. .

For example, as shown in Figure 4, a program such as music is recorded on the first track 4a of the magnetic tape 4, a time code is recorded on the second track 4b, and the middle section 4C is used to prevent crosstalk, etc. This is the unrecorded part.

The beginning part (head part) 4a' of the program can be found by the commonly used method, that is, by listening to the sound on a monitor.

For example, the tape 4 is hung on the ATR, and the output from the playback head is monitored as a playback state.

When the beginning part 4a' of the program is heard, the program is immediately stopped and the supply reel and take-up reel are manually rewound to find the beginning part 4a'.

However, the tape stops at this point, so the time code cannot be read.

The time code is read out during playback because the playback head is made of two track heads, so the upper track is used to read the program and the lower track is used to read the time code (not shown).
It's intimidating to read.

The present invention aims to eliminate the above-mentioned drawbacks and to provide a tape recorder that can automatically read the evening time code.

The present invention will be described in detail below with reference to FIGS. 1 and 2.

The tape recorder 1 has a tape guide 5 from a supply reel 2 to a take-up knoll 3. 6.13.14, the tape 4 is supplied through a group of heads such as the erasing head 8, the recording head 9, the playback head 10, etc., the pinch roller 12, and the capstan 11, and is played back by the operation button 7 arranged on the front of the tape recorder 1. Operations such as recording are threatened.

In such a tape recorder, the playback head 10 has a head gap 10b for reading the time code 4b and a head gap 10a for reading the program.

Now, as mentioned above, listen to the head position 4a' of the program, etc., and in this state, reverse the tape recorder and immediately stop it.
Put the tape recorder into playback mode a little before the beginning of the program.

The gate circuit 24 applied to the storage circuit 25 is opened at the moment the head 4a' of the program 4a is applied to the gap 10a of the playback head 10.

Therefore, the gear 10a of the program playback head 10
After amplifying the head portion signal of the program 4a extracted from the program 4a, the program signal is derived from the output terminal 21, and a part of the output of the amplifying circuit 20 is applied to a waveform shaping circuit 22 such as a Schmitt circuit, and the waveform shaping output is applied to the output terminal 21. Gate circuit 24
If the gate is opened for a period of two frames or less of the SMPTE time code, the time code signal from the time code detection gear 10b of the playback head 10 passes through the amplification circuit 23, the gate circuit 24, and the storage circuit. added to.

Although the time code stored in such a storage circuit is shown in the figure, it may be read out using a time code reader or the like.

Since the present invention is constructed as described above, it is possible to automatically read out the time code at the beginning of a program, and its practical effects are great.

[Brief explanation of the drawing]

Figure 1 is a plan view of the tape recorder of the present invention, Figure 2 is a system diagram of the present invention, Figure 3 is the SMPTE time code, and Figure 4 is the tape recorder of the present invention.
The figure is a tape pattern diagram for explaining the present invention. 1 is a tape, 2 and 3 are supply and take-up reels, 4 is a tape, 5. 6, 13, and 14 are guide rollers, 10 is a reproducing head, 15 is a magnetic head, 4a' is the program head position, and 4b is a time code.

Claims (1)

[Scope of utility model registration request] A tape recorder that creates a gate signal using the program recorded on magnetic tape and the program output in time code, opens the time code memory gate, and detects the time code at the beginning of the program.