KR920008482B1 - Synchronous recording and playing circuit of head converting - Google Patents

Abstract

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Description

Head switching circuit for simultaneous recording and playback of digital audio tapes

1 is a positional view of a head and a tape according to the prior art.

2 is a connection diagram in a drum according to the prior art.

3 is a positional view of the head and tape according to the present invention.

4 is a connection diagram in a drum according to the present invention.

5 is a drum structure according to the present invention.

6 is a timing diagram according to the present invention.

7 is a timing diagram according to the present invention.

* Explanation of symbols for the main parts of the drawings

10: phase pulse amplifier 20: NAND gate

30: switching signal generator 40: drum

50: first amplifier 60: second amplifier

70: multiplexer 80: demultiplexer

The present invention relates to a head control circuit used for a double deck in a digital audio tape recorder (hereinafter referred to as R-DAT), and in particular, a drum (DAT) A head switching circuit capable of recording and playing back at the same time.

In general, there is no conventional circuit in which two heads can simultaneously play and record DAT using a single drum in a double deck R-DAT. 1 is a positional view of a head and a tape according to the prior art, and FIG. 2 is a connection diagram in a drum according to the prior art.

This will be described in detail with reference to FIGS. 1 and 2. In FIG. 1, only one tape 2 is connected to one drum 1 in order to simultaneously play and record. In FIG. 1, a rotary trans is referred to as a connection in the drum of FIG. ) Core (C) is used. In the case of using the core C, the magnetic fluxes generated by the currents of the heads A and B of FIG. 2 interfere with each other, and thus the signal transmitted to each head cannot be a normal signal. The abnormal signal is applied to the amplifier (AMP) 3 and the signal is amplified by the amplifier 3, thereby causing abnormal tape playback and recording.

Accordingly, an object of the present invention is to provide a head switching circuit capable of simultaneously recording and playing back DAT without mutual interference between head and head signals by contacting two tapes with one drum in a double deck R-DAT. have.

Hereinafter, the present invention will be described in detail with reference to the drawings.

3 is a positional view of a head and a tape according to the invention, in which two tapes are used in contact with one drum 40 at the same time.

4 is a connection diagram in a drum according to the present invention, since two cores C1 and C2 are used in the drum 40 to use a shield plate 13 between two cores C1 and C2. Cores (C1, C2) were completely shielded.

5 is a drum structure according to the present invention, which comprises an upper drum (Upper / Drum: hereinafter referred to as U / D), a lower drum (Lower / Drum: hereinafter referred to as L / D), and a motor (M). And the head B1 are attached to the upper drum U / D.

6 is a timing diagram according to the present invention, FIG. 6a is a phase pulse generation signal, FIG. 6b is a switching pulse, FIG. 6c is data reproduced from the first tape 11, and FIG. 6d is a second tape 12. Data written to

7 is a circuit diagram according to the present invention, the configuration and operation of which will be described in detail with reference to FIGS.

The streamlines A1 and B1 are the heads and the drums 40 in the third, fourth, fifth and seventh degrees are the same drums 40 and act the same. The first and second tapes 11 and 12 are simultaneously brought into contact with a drum 40 of FIG. 3. The first tape 11 is used for reproducing and the second tape 12 is used for recording. When (A1, B1) passes the (b) position from the (a) position in Fig. 3, it is the playback mode and the recording mode when the (c) position passes the (d) position. The heads A1 and B1 in the drum 40 are mounted in opposite directions with respect to the center of the drum 40 so that the head B1 is in the (C) position when the head A1 is in the (a) position. . Also, as shown in FIG. 5, a phase pulse generator signal (hereinafter referred to as PG) is positioned at the same position as the head A1. Therefore, a phase pulse detector (called PGD) is installed at the position (a) of FIG. 2 so as to determine the positions of the heads A1 and B1.

In the drum 40, the upper drum U / D rotates together with the motor M, as shown in FIG. 5, and the PG is installed in the motor M corresponding to the same position as the head A1. . When the fifth drum 40 is rotated, a waveform is detected in the PGD installed at the position of FIG. 3 (a) as shown in FIG. 6a, and T1 represents drum rotation. First, when the first tape 11 is used in the playback mode and the second tape 12 is used in the recording mode, when the waveform shown in FIG. 6a is detected in the PGD, the waveform is applied to the phase pulse amplifier 10.

)로 인가된다. 상기 로우신호가 제1증폭기(50)로 인가되는 동시에 멀티플렉서(Mutiflexer : 70)의 셀렉터단자(S1)로도 인가된다. 상기 동작이 진행될때 제3도의 드럼(40)에서는 이 드럼(40)이 회전하므로 제7도 드럼(40)의 헤드(A1,B1)이 동작하여 RT1 및 RT2의 이차측에 전류가 흘러 이차측으로 유기된다.The waveform inputted to the phase pulse amplifier 10 is amplified by a predetermined output and output to the Shumit trigger NAND gate 20. The waveform input to the NAND gate 20 is shaped and output to the switching signal generator 30. The waveform input to the switching signal generator 30 outputs a switching pulse (SWP). The output becomes a low signal in drum rotation, as shown in FIG. 6b, and the recording and reproduction selection of the first amplifier 50 is performed. Terminal (R1 /

Is applied. The low signal is applied to the first amplifier 50 and also to the selector terminal S1 of the multiplexer 70. When the operation is in progress, the drum 40 rotates in the drum 40 of FIG. 3 so that the heads A1 and B1 of the drum of FIG. 7 operate so that current flows to the secondary side of the RT1 and RT2 to the secondary side. Become organic.

)가 재생모드가 선택되므로 재생신호(PB1)가 출력하여 멀티플렉서(70)의 입력단자(i0)로 입력된다.The induced signal is applied to the first and second amplifiers 50 and 60 so that the recording and reproduction selection terminal R1 / of the first amplifier 50 is applied.

Since the playback mode is selected, the playback signal PB1 is outputted and input to the input terminal i0 of the multiplexer 70.

)로 인가된다. 또한 상기 로우신호가 디멀티플렉서(Demultiflexer : 80)의 셀렉터 단자(S2)로 인가된다.The signal input to the multiplexer 70 outputs the reproduction signal PB_ to the first tape 11 through the output terminal D ₀ by the selector terminal S1. The reproduction signal is as shown in part (c) of FIG. 6c and as in part (b) of FIG. 6c when the head A1 rotates in a portion where the drum 40 does not contact the tape. The low signal of the switching pulse SWP becomes a high signal through the inverter G, so that the recording / playback selection terminal R2 / of the second amplifier 60 is applied.

Is applied. The low signal is also applied to the selector terminal S2 of the demultiplexer 80.

)가 녹음모드가 선택되므로 녹음신호(REC2)단자가 디멀티플렉서(80)의 출력단자(O0)와 연결된다.Then, the recording and playback selection terminal R2 / of the second amplifier 60 is performed.

Since the recording mode is selected, the recording signal REC2 is connected to the output terminal O0 of the demultiplexer 80.

The recording signal RECI is input to the input terminal Di of the demultiplexer 80 and output to the second amplifier 60. Since the input signal of the second amplifier 60 is applied to the drum 40 and recorded on the second tape 12, the input signal of the second amplifier 60 is the same as the portion (a) of FIG. 6d, and the portion where the tape and the drum 40 are not in contact. When the head B1 turns, it is the same as (b) of FIG. 6d.

)로 인가되어 드럼(40)으로부터 인가되는 신호에 녹음모드가 선택된다.The operation of the drum 40 separates the two cores C1 and C2 so that mutual interference between signals is excluded. The switching pulse SWP output from the switching signal generator 30 is a high signal in the waveform of FIG. Recording playback select terminal R1 / of the first amplifier 50 when

Recording mode is selected for the signal applied from the drum 40.

)로 입력된다.Since the recording mode is selected, the recording signal REC1 is output and connected to the output terminal 01 of the demultiplexer 80. In addition, as the high signal of the switch pulse SWP is input to the demultiplexer 80 selector terminal S2, the recording signal RECI is input to the input terminal Di, and thus is output to the second amplifier 60. The recording signal input to the second amplifier 60 is applied to the drum 40 and recorded on the second tape 12. The recording is the same as the portion (c) of FIG. 6d, and the portion (d) of FIG. 6d when the head A1 is a portion where the drum 40 and the tape are not in contact. The high signal of the switching pulse SWP is inverted through the inverter G so that the low signal is selected as the recording / playback selection terminal R2 / of the second amplifier 60.

) Is entered.

The reproduction signal PB2 is connected to the input terminal i1 of the multiplexer 70 by the low signal. The multiplexer 70 inputs a high signal through the selector terminal S1 to output the reproduction signal PB_ to the first tape 11 through the output terminal D_.

The reproduction signal is the same as the portion (c) of FIG. 6c, and the portion (d) of FIG. 6c when the head B1 rotates in the portion where the drum 40 and the tape do not contact. This allows simultaneous playback and recording on the DAT.

As described above, in the double-deck R-DAT, two tapes are contacted using one drum to improve the reliability of the product with a simple circuit that can simultaneously record and play back the DAT without mutual interference between the signals of the two heads. There is an advantage to this.

Claims (1)

In the head control circuit for recording and reproducing a digital deck of digital audio tape comprising a phase pulse amplifier 10 connected to a pulse generating detector PGD and a NAND gate 20 and a switching signal generator 30, the two heads. The drum is separated from the two cores so as to completely eliminate the interference between the drums, so that the drum 40 can simultaneously record and play back with a normal signal, and the drum 40 can be connected to the drum 40 of the switching signal generator 30. Since the input signal is selected according to the output signal to select the recording and playback mode, the first amplifier 50 capable of amplifying and outputting the recording and playback signals, and the switching signal generator 30 in connection with the drum 40. Selects the recording and playback mode by inverting the signal according to the output signal of the second amplifier and outputs the second amplifier 60 and the first and second amplifiers capable of amplifying and outputting the recording and playback signals. The multiplexer 70 capable of outputting a reproduction signal by the selection terminal when the selection mode of the devices 50 and 60 is the reproduction mode, and the selection mode when the selection modes of the first and second amplifiers 50 and 60 are the recording mode. And a demultiplexer (80) capable of inputting a recording signal by a terminal and outputting the recording signal to the first and second amplifiers (50, 60).

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