JPH0536006A - Magnetic recording and reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] When reproducing a video signal containing noise above a certain reference level, in a magnetic recording / reproducing apparatus in which two recording media can be inserted in the same device and each recording medium can be recorded or reproduced. It is an object of the present invention to provide a magnetic recording / reproducing device capable of solving a change in the luminance level of a required video signal. [Structure] It is necessary to pass the EE circuit 13 by switching the third switching circuit 20 to the second reproducing circuit 18 when the second reproducing circuit 18 reproduces a video signal containing noise above a certain reference level. It is possible to obtain a magnetic recording / reproducing apparatus that does not change the luminance level of a video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a video tape capable of inserting two recording media (hereinafter referred to as magnetic tapes) in the same device, recording and reproducing the first magnetic tape, and reproducing the second magnetic tape. The present invention relates to a recorder (hereinafter referred to as VTR).

[0002]

2. Description of the Related Art In recent years, with the spread of video cameras and the like, VTRs have come to be widely used for editing magnetic tapes created by individuals. In order to eliminate the complexity of connecting and controlling two devices, a A VTR capable of inserting two magnetic tapes has been developed.

A conventional magnetic recording / reproducing apparatus will be described below. FIG. 2 is a block diagram of a recording / reproducing circuit of a conventional VTR. In FIG. 2, 31 is an external input terminal, 32 is a first switching circuit, and either the external input terminal 31 or the second reproducing circuit 38 is selected according to a preset state. 33 is an EE circuit (elec)
tric to electric), the AGC circuit which corrects the level of the signal selected by the first switching circuit 32, the Y / C separation circuit which divides the input signal into the luminance signal and the color signal, and the like. 34 is a second switching circuit for switching the first reproducing circuit 35 and EE circuit 33, 36 is a recording circuit, 3
7 is a video head, 38 is a second reproducing circuit, 39 is a second video head, and 40 is an output terminal.

The operation of the magnetic recording / reproducing circuit configured as described above will be described below. First, a case where the second magnetic tape is reproduced and recorded on the first magnetic tape will be described. The second magnetic tape is reproduced from the video head 39 by the second reproducing circuit 38. Furthermore, the signal of the external input terminal 31 or the second reproducing circuit 38 is switched by the first switching circuit 32, and the EE circuit 3 is used during recording.
The output of No. 3 is processed by the recording circuit 36 and recorded from the video head 37 to the first magnetic tape. At this time, the second switching circuit 34 selects the EE circuit 33, and the EE circuit 33 is output to the output terminal 40.

On the other hand, at the time of reproducing the first magnetic tape, the output signal of the video head 37 is selected by the second switching circuit 34 via the first reproducing circuit 35, so that the first reproducing circuit 35 outputs the signal. To be done.

[0006]

However, in the above-mentioned conventional configuration, the output of the second reproducing circuit 38 passes through the EE circuit 33 through the first switching circuit 32, so that a signal above a certain reference level is output to the second level. When output from the reproducing circuit 38, the AGC circuit forming the EE circuit 33 has a problem that the luminance level of the video signal changes.

An example of the above problem will be described with reference to FIG. In FIG. 3, reference numeral 41 is a video signal input to the EE circuit 33, and 42 is noise included in the input video signal 41 and having a certain reference level or higher. Reference numeral 44 is a video signal output from the AGC circuit 43, and 45 is noise included in the output video signal 44. The input video signal 41 including the noise 42 of a certain reference level or more is level-corrected including the peak of the noise 42 by passing through the AGC circuit in the EE circuit, so that the luminance level of the necessary video signal is lowered and apparently. It looks dark.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a circuit that does not change the luminance level of a video signal portion required even in a video signal containing noise above a certain reference level. To do.

[0009]

In order to achieve this object, the magnetic recording / reproducing apparatus of the present invention is capable of inserting two magnetic tapes in the same device and recording / reproducing the first magnetic tape. A reproduction circuit, an EE circuit, a recording circuit, a second reproduction circuit capable of reproducing the second magnetic tape, a first switching circuit for switching the output of the second reproduction circuit and at least one external input, The second switching circuit for switching the switching circuit and the first reproducing circuit, and the third switching circuit for switching the outputs of the second switching circuit and the second reproducing circuit.

[0010]

With this configuration, the third switching circuit is provided so as to pass through the EE circuit even when the reproduction circuit output is above a certain reference level, and the third switching circuit switches the third switching circuit to the third switching circuit. It is possible to switch the switching circuit, and it is possible to transmit the original information without changing the luminance level of a required signal portion even in a video signal containing noise above a certain reference level.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

In FIG. 1, 11 is an external input terminal and 12
Is a first switching circuit for switching the second reproducing circuit 18 and the external input terminal 11, 13 is an EE circuit, 14 is a second switching circuit for switching the first reproducing circuit 15 and the EE circuit 13, 1
5 is a first reproducing circuit, 16 is a recording circuit, 17 is a video head, 18 is a second reproducing circuit, 19 is a second video head, and 20 is a second reproducing circuit 18 and a second switching circuit 14. A third switching circuit for switching the output, 21 is a switch control circuit, 22 is an output terminal of the third switching circuit 20, 2
Reference numeral 3 is an output terminal of the second reproducing circuit 18.

The operation of the magnetic recording / reproducing apparatus configured as described above will be described. First, a case where the second magnetic tape is reproduced and recorded on the first magnetic tape will be described. The second magnetic tape is reproduced from the video head 19 by the second reproducing circuit 18 and selected by the first switching circuit 12. The output of the first switching circuit 12 is recorded on the first magnetic tape by the video head 17 from the recording circuit 16 via the EE circuit 13. At this time, the second switching circuit 14
Since the E circuit 13 is selected and the third switching circuit 20 selects the second reproduction circuit 18 by the switch control circuit 21, the video output is the second reproduction circuit 18.

Next, a case where both the first magnetic tape and the second magnetic tape are being reproduced will be described. The second magnetic tape is reproduced from the video head 19 by the second reproducing circuit 18. The first magnetic tape is reproduced from the video head 17 by the first reproducing circuit 15. At this time, the second switching circuit 14 selects the first reproducing circuit 15,
Since the third switching circuit 20 selects the second switching circuit 14 by the switch control circuit 21, the video output is the first reproduction circuit 15.

That is, the switch control circuit 21 is controlled so that the first reproducing circuit 15 is preferentially selected when the first magnetic tape is reproducing. Also, the first magnetic tape is not played, the second magnetic tape is played, and
When the first switching circuit 12 is selecting the second reproducing circuit 18, it is controlled to select the second reproducing circuit 18.

As described above, according to this embodiment, two magnetic tapes can be inserted into the same device, and the first reproducing circuit and the EE circuit, the recording circuit and the second recording circuit capable of recording and reproducing on the first magnetic tape. By providing a reproducible second reproducing circuit on the magnetic tape and a third switching circuit for switching the output of each reproducing circuit, the EE circuit can be used even when reproducing a video signal containing noise above a certain reference level. Therefore, it is possible to adopt a circuit configuration that passes the above condition, and it is possible to keep the required luminance level of the video signal portion unchanged.

It is needless to say that the external input terminal 11 and the first switching circuit 12 may be omitted in the embodiment of FIG.

[0018]

As described above, according to the present invention, two magnetic tapes can be inserted in the same device, and the first reproducing circuit capable of recording and reproducing on the first magnetic tape, the EE circuit, the recording circuit and the second circuit. By providing a second reproduction circuit that can reproduce on the magnetic tape and a third switching circuit that switches the reproduction output of the two magnetic tapes, a video signal that is also required for a video signal that contains noise above a certain reference level It is possible to realize an excellent magnetic recording / reproducing apparatus capable of transmitting the original information without changing the luminance level of a part.

[Brief description of drawings]

FIG. 1 is a block diagram of a video signal processing system of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a video signal processing system of a conventional magnetic recording / reproducing apparatus.

FIG. 3 is a signal waveform diagram in a conventional device.

[Explanation of symbols]

 11 External Input Terminal 12 First Switching Circuit 13 EE Circuit 14 Second Switching Circuit 15 Playback Circuit 16 Recording Circuit 17 Video Head 18 Second Playback Circuit 19 Second Video Head 20 Third Switching Circuit 21 Control Circuit 22 Output terminal 23 Output terminal

Claims (1)

Claim: What is claimed is: 1. A first reproduction circuit and a recording circuit capable of inserting two recording media in the same device and capable of recording and reproducing on the first recording medium, and reproducing on the second recording medium. A possible second regeneration circuit, a first switching circuit for switching the output of the second regeneration circuit and at least one external input, and a second switching circuit for switching the first switching circuit output and the first regeneration circuit output. And a third switching circuit for switching the output of the second switching circuit and the output of the second reproducing circuit.