JP2697127B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus which improves image quality deterioration caused by a flying erase circuit added for the purpose of improving editing accuracy of a VTR or the like.

2. Description of the Related Art HiFi VTRs have become widespread in recent years, and with the release of video movies, the editing function and editing accuracy of home VTRs have attracted attention. This will be described below with reference to the drawings.

Conventional examples are shown in FIG. 3 and FIG. In FIG. 3, VT
The first in which the recording amplifier circuit of the magnetic recording / reproducing device such as R is arranged
A recording amplifier circuit 1 for recording a video signal, a recording amplifier circuit 2 for recording an audio signal, and a flying erase circuit 3 are arranged on the printed circuit board. 4 is recorded on a magnetic tape by a rotary head 10 via a rotary transformer 7. The recording current of the audio signal is recorded on the magnetic tape by the rotary head 11 from the second printed circuit board 5 via the rotary transformer 8 when the switch 14 is turned on. Further, the erasing current of the flying erase erases from the second printed circuit board 6 via the rotary transformer 9 by the rotary head 12 on the track on which the video signal and the audio signal are already recorded on the magnetic tape or on the track to be recorded from now on. . At this time, since the ground points 15 and 16 of the video signal and audio signal recording amplifier circuits arranged on the same substrate and the ground point 17 of the flying erase circuit are on the same substrate, a common impedance is established between them and the main ground. have. This pattern is shown in FIG. In FIG. 4, the ground 22 of the video signal recording amplifier circuit of the recording amplifier block is connected to the main ground 21 via the ground 25, and the ground 23 of the audio signal recording amplifier circuit is connected to the main ground 21 via the ground 25, The ground 24 of the flying erase circuit is connected to the main ground 21 via the ground 25, and the erasing current of the flying erase is supplied from the cold side of the flying erase head via the ground 26 of the second printed circuit board to the recording amplifier block by the connecting means 32. Is connected to the main ground via a connection point 28 of the rotary cylinder block and a connection point 30 of the rotary cylinder block.

However, in the configuration of the ground pattern as described above, a common impedance intervenes in the erase current loop of the flying erase circuit and the recording current loop in the video signal and the audio signal, and the flying erase erase current flows. When the recorded portion is reproduced during the recording, there is a problem that a beat, which is one of the causes of image quality deterioration, occurs.

The present invention has been made in view of the above problems, and even if a recording amplifier circuit for recording a video signal, a recording amplifier circuit for recording an audio signal, and a flying erase circuit are arranged on the same printed circuit board, the manner of grounding the flying erase circuit is changed, It is an object of the present invention to provide a magnetic recording / reproducing apparatus in which a common impedance is hardly provided in a recording current loop of a signal and an audio signal, thereby suppressing a beat at the time of reproduction and causing no deterioration in image quality.

Means for Solving the Problems In order to solve the above problems, the present invention provides a video signal recording amplifier circuit, at least one of audio signal recording amplifier circuits, and a flying erase circuit on the same printed circuit board. A first printed circuit board arranged, connecting means for arranging the ground of a circuit other than the second printed circuit board provided with the rotary head and the flying erase circuit on the first printed circuit board and connecting to the main ground, and a flying erase circuit Ground in the first printed circuit board, and
Connecting means for arranging the ground of the flying erase circuit and the ground of the flying erase head in the second printed circuit board to connect to the main ground. .

The present invention relates to a magnetic recording / reproducing apparatus having a printed circuit board in which both or any one of a video signal recording amplifier circuit and an audio signal recording amplifier circuit and a flying erase circuit are arranged on the same printed circuit board. The ground of the flying erase circuit of the printed circuit board is arranged on the second printed circuit board provided with the rotary head, and is separated from the ground of the video signal recording amplifier circuit and / or the audio signal recording amplifier circuit. Thus, the beat phenomenon that occurs when a portion recorded during the flying erase operation is reproduced is suppressed, and the image quality is prevented from deteriorating.

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

On a first printed circuit board on which a recording amplifier circuit of a magnetic recording / reproducing device such as a VTR is arranged, a recording amplifier circuit 1 for video signals, a recording amplifier circuit 2 for audio signals, and a flying erase circuit 3 are arranged. A rotary head having rotary cylinder blocks 4 to 6 is provided on the second printed circuit board. The recording current of the video signal is recorded on the magnetic tape by the rotary head 10 via the rotary transformer 7 from the rotary cylinder block 4 of the second printed circuit board when the switch 13 is turned on. The recording current of the audio signal is recorded on the magnetic tape by the rotary head 11 via the rotary transformer 8 from the rotary cylinder block 5 of the second printed circuit board when the switch 14 is turned on. Further, the erase current of the flying erase is supplied from the rotating cylinder block 6 of the second printed circuit board via the rotary transformer 9 by the rotary head 12 to the track on which the video signal and the audio signal are already recorded on the magnetic tape or the track to be recorded from now on. Erase the top. At this time,
The ground points 15 and 16 of the video signal and audio signal recording amplifier circuits disposed on the same substrate are connected to the ground point 18 and the ground point 17 of the flying erase circuit on the second printed circuit board and are connected to the main ground. ing. FIG. 2 shows the ground pattern at this time. In FIG. 2, the ground 22 of the recording amplifier circuit of the video signal of the recording amplifier block.
Is connected to the main ground by merging with the ground 23 of the audio signal recording amplifier circuit, and the ground 24 of the flying circuit is connected by the connecting means 32 to the connection point 28 of the first printed circuit board and the connection point 30 of the second printed circuit board. Is connected to the ground 26 of the second printed circuit board, and the flying erase current is connected to the ground of the flying erase circuit by the ground 26 from the cold side of the flying erase head and is connected to the main ground 33 of the second printed circuit board. Also, the main earth 21
And 33 are connected by the connecting means 31 to the connection points 27 of the first printed circuit board.
Is connected via a connection point 29 of the second printed circuit board.

Effects of the Invention As described above, the present invention provides at least one of a video signal recording amplifier circuit and an audio signal recording amplifier circuit,
A first printed circuit board having a flying erase circuit arranged on the same printed circuit board, a second printed circuit board having a rotating head, and a ground other than the flying erase circuit arranged on the first printed circuit board and connected to a main ground. Connecting means for connecting the ground of the flying erase circuit to the second printed circuit board independently of the ground of the flying erase circuit, and connecting the ground of the flying erase circuit and the ground of the flying erase head to the second printed circuit board. By providing a connection means that connects inside the board and connects to the main ground, the beat component recorded during the operation of the flying erase circuit is suppressed, and while the editing function is fully performed, the generation of beat which is a factor of image quality degradation is generated. It is possible to obtain an excellent effect such as prevention.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an earth pattern diagram showing details of the block diagram of FIG. 1, FIG.
The figure is a detailed ground pattern diagram of a conventional example. 1,2,3 …… Amplifier, 4,5,6 …… Rotary converter, 7,8,9…
… Rotary transformer, 10,11,12 …… Rotating head, 13,1
4… Switch, 15,16,17,18 …… Earth point, 21 ~
26,33 …… Earth pattern, 27-30 …… Connection point, 31,32…
... connection means.

Claims (1)

(57) [Claims] 1. A magnetic recording / reproducing apparatus for magnetically recording at least one of a video signal and an audio signal by a rotary head, comprising: a video signal recording amplifier circuit; an audio signal recording amplifier circuit; A first printed circuit board provided on the same printed circuit board, a second printed circuit board provided with a rotating head, and a ground for circuits other than the flying erase circuit on the first printed circuit board. Connecting means for arranging and connecting to the main ground, connecting means for making the ground of the flying erase circuit independent in the first printed circuit board and arranging it on the second printed circuit board, earth for the flying erase circuit, and flying erase Magnetic recording / reproducing comprising: connecting means for connecting the ground of the head within the second printed circuit board and connecting to the main ground. Location.