JPH0362307A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To give a shielding effect, to prevent crosstalk from occurring among respective channels and to minizturize a rotating transformer at the same time by arranging coils for transmitting the signal of the rotating transformer so that they are not adjacent to coils which are used at the same time and executing short-circuit for the coils in a mode which is not used. CONSTITUTION:When recording and reproducing are executed in a standard mode, the coils 9e and 9h, 9a and 9c of the rotating transformer 7 corresponding to a standard mode video head, a standard mode voice recording and reproducing and voice intermittent recording head are used. The short-circuit is executed for the other coils 9b and 9d, 9f and 9g by transistors 11b, 11d, 11f and 11g. When the recording and the reproducing are executed in a time lapse mode, the coils 9e and 9h, 9a and 9c are executed in a time lapse mode, the coils 9e and 9h, 9a and 9c are used and the short-circuit is executed for the other coils 9b and 9d, 9f and 9g at the recording time. Besides, the coils 9e and 9h, 9b and 9d are used and the short-circuit is executed for the other coils 9a and 9c, 9f and 9g by the transistors 11a, 11c, 11f and 11g at the reproducing time. In such a way, the crosstalk is prevented from occurring among the coils which transmit the signal and the waveform of the signal is prevented from being deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus that records audio in a temporally compressed manner.

2. Description of the Related Art In recent years, magnetic recording and reproducing devices have become more sophisticated and multi-functional, and intermittent recording type VTRs used for monitoring purposes are now recording not only video but also audio by compressing the time axis. The number of heads and the corresponding rotary transformers are also increasing with more coils.

An example of a conventional magnetic recording/reproducing device will be described below with reference to the drawings.

FIG. 5 shows a rotary transformer of a conventional magnetic recording/reproducing apparatus. In FIG. 5, 16.17 is the stator and rotor of the first rotary transformer, and 1918 is the stator and rotor of the second rotary transformer. Also 14a, 14
b, 14c, and 14d are audio signal transmission coils of the first rotary transformer; 13a, 13b, and 13c, 13d;
are video signal transmission coils of the second rotary transformer, respectively. Further, 15a, 15b, and 15c are short-circuited coils that act as magnetic sealing materials to prevent crosstalk between the respective channels of the first rotary transformer. 15d, 15e, and 15f are short-circuited coils that act as magnetic shielding materials for preventing crosstalk of the second rotating transformer, respectively. The rotors 17 and 18 are fixed to each other by the same rotating shaft (not shown).

The operation of the magnetic recording/reproducing apparatus configured as described above will be explained below.

Signals transmitted during recording or reproduction are distorted within the rotating transformer due to crosstalk between channels. Therefore, as described above, a short-circuited coil that acts as a magnetic shield material is inserted between each channel of the rotary transformer to prevent crosstalk between the channels within the rotary transformer.

Problems to be Solved by the Invention However, as mentioned above, for example, in a device with 8 rotating heads, 4 heads for video and 4 heads for audio, a short circuit coil for shielding is required. The rotary transformer alone is too large, and it becomes necessary to divide the rotary transformer into two sets, and the mechanism for holding the rotary transformer becomes complicated and expensive.

In view of the above-mentioned problems, the present invention provides a magnetic recording and reproducing device in which the rotating transformer is made smaller and the cost is reduced.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording and reproducing apparatus of the present invention has two heads for standard mode recording and reproducing for video, two heads for special reproduction, and two heads for standard mode recording and reproducing for audio. Two heads for mode recording/playback and intermittent recording, two heads for intermittent playback, a rotary transformer that transmits signals to each of the eight rotating heads, and a rotary transformer for standard mode recording/playback. The coils for transmitting intermittent recording audio signals and the coils for transmitting intermittent audio reproduction signals are arranged alternately, and the coils for transmitting standard mode video signals and the coils for transmitting video signals for special reproduction are arranged alternately. In addition, short-circuiting means is provided for short-circuiting coils in an unused mode between each coil of the rotary transformer and a recording/reproducing amplifier connected thereto.

Effect of the Invention With the above-described configuration, the present invention provides a shielding effect by arranging the coils for transmitting signals of the rotary transformer such that coils that are used at the same time are not adjacent to each other, and by short-circuiting the coils that are in a mode that is not used. As a result, crosstalk between channels can be prevented, and the rotary transformer can be downsized.

EMBODIMENT A magnetic recording/reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a rotary head device of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a fixed lower cylinder to which a bearing 2 is fixed, and a rotary shaft 3 is supported by the bearing 2. A disk 4 is attached to the rotating shaft 3, and an upper cylinder 5 and a rotor 6 side of the rotation transformer are attached to the disk 4. A stator 7 side of a rotary transformer is fixed in the lower cylinder 1, and the rotor 6 and stator 7 face each other with a predetermined gap.

FIG. 2 shows the arrangement of eight heads arranged at the bottom of the upper cylinder 5. 8e and 8h are standard mode video recording/playback heads, 8f and 8g are special playback heads, 8a and 80 are standard mode audio recording/playback and audio intermittent recording heads, 8
b and 8d are heads for intermittent audio reproduction.

FIG. 3 is a configuration diagram of each signal transmission coil of the rotary transformer. As described above, the rotor 6 side and the stay 27 side of the rotary transformer face each other with a predetermined gap. -9
e and 9h are standard mode video recording/playback signal transmission coils, 9f
and 9g are coils for transmitting special playback video signals, 9a and 90 are coils for standard mode audio recording/reproduction and transmitting recording signals during audio intermittent times, and coils 9b and 9d are coils for transmitting playback signals during audio intermittent times.

FIG. 4 shows the circuit configuration. The rotating heads 8a to 8h and the primary coils 10a to 10h of the rotating transformer are connected as shown in FIG. Secondary coil 9a of rotating transformer
-9h are connected to playback amplifiers 12a-12d and recording amplifiers 12e-12h, respectively. The collectors and emitters of transistors lla to llh are connected to both ends of the secondary coil as means for shorting the signal transmission path between the secondary coil and the recording/reproducing amplifier.

The operation of the magnetic recording/reproducing apparatus configured as above will be described below.

Table 1 below shows the state of each mode and whether the rotating transformer is short-circuited or not. The ○ mark indicates that it is being used for signal transmission, and the × mark indicates that it is short-circuited.

(Left below) For example, in the case of standard mode recording and playback, coils 9e and 9h, 9a and 9C of rotary transformers corresponding to the standard mode video head and the standard mode audio recording/playback/audio intermittent recording head.
are used, and the other coils 9b and 9d, 9f and 9g are transistors 11b.

It is short-circuited by lid, llf, and l1g. Similarly, when in time-lapse mode, when recording, use 9e in the table.
and 9h, 9a and 90 coils are used, and the other 9b and 9 coils are used.
d, 9f and 9g are shorted. When playing again, 9
Coils e, 9h, 9b and 9d are used, and the other coils 9a, 9c, 9f and 9g are transistors lla, llc, ll.
f, short-circuited by l1g. By doing this, in all modes, there is a short-circuited coil between the coils used, and this coil acts as a shielding material, preventing crosstalk between the coils transmitting signals. Therefore, deformation of the waveform of the recording signal or reproduction signal can be prevented.

Effects of the Invention As described above, the present invention has a total of four heads for video, two heads for standard mode and two heads for special playback, and for audio, two heads for standard mode recording/playback and intermittent audio recording.
4 heads in total, 2 heads for intermittent playback, 8 heads in total, 8
A rotary transformer for transmitting signals to the rotary head, a coil for transmitting a recording signal during intermittent audio recording and a coil for transmitting a reproducing signal during intermittent audio for standard mode recording and reproducing are arranged so as to be alternately located, and the standard mode video The signal transmission coil and the special reproduction video signal transmission coil are arranged alternately, and by providing means for short-circuiting each coil between the rotary transformer and the recording/reproducing amplifier connected thereto, all In this mode, there is always a short-circuited coil between the coils that transmit the signal of the rotating transformer, and to prevent crosstalk between the coils that transmit the signal, it is necessary to apply shielding material to the rotating transformer. This eliminates the need to use a rotary transformer, making it possible to realize a small and inexpensive rotating transformer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a rotary head device of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a head arrangement of the rotary head, and FIG. 3 is a layout of each signal transmission coil of a rotary transformer. Figure 4 is a circuit diagram around the rotating transformer, Figure 5A
, B is a sectional view of a rotary transformer of a conventional magnetic recording/reproducing device. ■...Lower cylinder, 2...Bearing, 3.
... Rotating axis, 4 ... Upper cylinder, 5 ...
... Disc, 6 ... Rotating transformer (rotor side), 7 ... Rotating transformer (stator side),
8e, 8h...Standard mode head for video, 8f
, 8g...Special playback head, 8a, 8c...
...Standard mode audio recording/reproducing head for audio intermittent recording, 8b, 8d...Head for audio intermittent playback, 9
a. 9c... Secondary coil for transmitting recorded signals during no-speech intermittent periods for standard mode audio recording and playback, 9b, 9d... Secondary coils for transmitting playback signals during intermittent audio periods, 9e, 9h・・・
...Secondary coil for video standard mode signal transmission, 9
f. 9g... Secondary coil for transmitting special playback video signals, 10a, 10c... Primary coil for transmitting intermittent no-sound recording signals for standard mode audio recording and playback, 10b, 10
d...Primary coil for audio intermittent playback signal transmission, 10e, 10h...Primary coil for video standard mode signal transmission, 10f, 10g...Special Primary coil for transmitting reproduced video signals, lla to 11h...
...Short circuit transistors, 12a to 12d...
・Reproduction amplifier, 12e to 12h...Recording amplifier.

Claims (1)

[Claims] For video, there are two heads for standard mode recording and playback, two heads for special playback, and for audio, there are two heads for standard mode recording and playback and intermittent recording, and two for intermittent playback.
A rotary transformer that transmits signals to each of the eight heads, a coil for standard mode audio recording/playback and intermittent audio recording signal transmission, and a coil for transmitting an audio intermittent reproduction signal alternately. and arranged so that the standard mode video signal transmission coil and the special playback video signal transmission coil are alternately located,
A magnetic recording/reproducing apparatus comprising short-circuiting means for short-circuiting coils in an unused mode between each coil of the rotary transformer and a recording/reproducing amplifier connected thereto.