JPS59207040A - Magnetic sound recording and reproducing device - Google Patents

Abstract

PURPOSE:To invert a magnetic tape automatically even during running of the magnetic tape by detecting that signal obtained from a reproducing head is broken over a fixed time and inverting automatically the running direction of the magnetic tape by this detection output. CONSTITUTION:If a no-signal part t1 is detected, the output of a no-signal part detecting circuit 5 is in the high level only during the time of the no-signal part as shown in the Fig. B, and the output of a delay circuit 6 becomes high- level after a certain time t0 as shown in the Fig. C. Since t1<t0 is true in this case, the output of a comparing circuit 7 is in the low level as shown in the Fig. D, and a plunger driving circuit 8 is not operated. If a no-signal part t3 is detected, the output of the circuit 5 becomes as shown in the Fig. E, and the output of the delay circuit 6 becomes as shown in the Fig. F. Consequently, the output of the comparing circuit 7 becomes high-level as shown the Fig. G, and the plunger driving circuit 8 is operated, and the running direction of the magnetic tape is inverted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a so-called auto-reverse type magnetic recording and reproducing device capable of automatically reversing.

Conventional configuration and its problems In general, when automatically reversing the running direction of a magnetic tape in an auto-reverse type magnetic recording/playback device, (1) a metal foil attached to the end of the magnetic tape is used to detect the end of the tape; A method for issuing a reversal command and reversing when the switch is short-circuited (2) A method for optically detecting the leader tape provided at the end of the magnetic tape and issuing a reversal command for reversing (3) End of the magnetic tape A method is adopted in which a reversal command is issued and the reversal is performed based on the fact that the motor becomes locked and the torque increases. However, in all of these cases, there is a problem in that the magnetic tape does not automatically reverse unless it is run to the end. Therefore, even if recording has only been done halfway down the magnetic tape and all the rest is unrecorded, the magnetic tape will continue to be played until the end of t8, and will be automatically reversed in the middle to play another track. It was not possible to play the .

OBJECTS OF THE INVENTION It is an object of the present invention to provide a magnetic recording and reproducing device that can automatically reverse the magnetic tape even while it is running.

Structure of the Invention In order to achieve the above-mentioned object, the magnetic recording and reproducing apparatus of the present invention is characterized in that it is provided with a detection circuit that detects when the signal obtained from the reproducing head is no longer than a certain value Ii'. be. According to this configuration, when the signal obtained by the reproducing head is interrupted in a fixed manner from 1'i+ to -L, at this point, the output of the detection circuit issues a reversal command to automatically reverse the running direction of the magnetic tape. , the running direction of the magnetic tape can be automatically reversed. This has the advantage that the magnetic tape can be automatically reversed even while it is running, the playback time can be shortened even when the magnetic tape is only halfway recorded, and the magnetic tape can be efficiently played back and forth.

DESCRIPTION OF EMBODIMENTS The magnetic recording and reproducing apparatus of the present invention will be described below with reference to drawings of embodiments. In FIG. 1, 1 is a playback head;
2 is a head amplifier, 3 is a power amplifier, and 4 is a speaker. 5 is a no-signal portion detection circuit for detecting a no-signal portion of the signal reproduced by the playback head 1; 6 is a delay circuit for delaying the output of the no-signal portion detection circuit 5; and 7 is a no-signal portion detection circuit for detecting the no-signal portion detection circuit 5. A comparator circuit for comparing the output with the output of the delay circuit 6, and 8 an inverting plunger drive circuit driven by the output of the comparator circuit Y.

The above-mentioned no-signal portion detection circuits are configured so that an output of level . . The comparison circuit 7 is composed of an AND circuit or the like that generates a high-level output when the output of the delay circuit 6 and the output of the no-signal portion detection circuit 5 are both high-level.

In the above embodiment, it is assumed that signals are currently recorded on the magnetic tape as shown in FIG.

In Figure 2, the shaded area is the area where the signal is recorded, and the blank area t1. t2. t3 indicates a no-signal portion.

When a no-signal portion t1 is detected, the output of the no-signal portion detection circuit 6 becomes high level for that period only as shown in FIG. 2B, and the output of the delay circuit 6 remains constant as shown in FIG. 2C. Time t. He wakes up and reaches the level of no-evil. However, in this case, 1. ,<,,1. Therefore, the output of the comparison circuit 7 is at a low level as shown in the second diagram, and the plunger drive circuit 8 does not operate.

Now, if a no-signal portion t3 is detected, the output of the no-signal portion detection circuit 6 will be as shown in FIG. 2E, and the output of the delay circuit 6 will be as shown in FIG. 2F.

Therefore, in this case, the output of the comparator circuit 7 is shown in FIG.
As shown in the figure, the level becomes high, the plunger drive circuit 8 operates, and the running direction of the magnetic tape is reversed.

As described above, according to the above embodiment, the signal reproduced by the reproduction head lasts for a certain period t. If the magnetic tape is interrupted, the running direction of the magnetic tape can be automatically reversed.

Effects of the Invention As described above, according to the magnetic recording and reproducing apparatus of the present invention, when the signal obtained by the reproducing head is interrupted for a certain period of time or more, the running direction of the magnetic tape can be automatically reversed. Even though this part is a non-signal part, the magnetic tape is not run to the end, and another track can be immediately played back, making it possible to improve the efficiency of round-trip playback time. It has the advantage of

[Brief explanation of the drawing]

FIG. 1 is a schematic electrical connection diagram of an embodiment of the magnetic recording/reproducing apparatus of the present invention, and FIG. 2 is an explanatory diagram of the operation of the apparatus. 1...Playback head, 2...Head amplifier, 3
...Power amplifier, 4...Speaker, 6...
...No signal portion detection circuit, 6...Delay circuit, 7
...Comparison circuit, 8...Plunger drive circuit for reversal.

Claims (1)

[Claims] (The signal obtained from the playback head during internal reproduction is
A magnetic recording and reproducing device is provided with a detection circuit for detecting when the magnetic tape runs out and is configured to automatically reverse the running direction of the magnetic tape based on the output of the detection circuit.