JP2005190601A - Rotary magnetic head type recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary magnetic head type recording and reproducing device which realizes a multichannel head without increasing signal cross talk in a rotary transformer mounted in a rotating drum. <P>SOLUTION: A rotary transformer 20 consists of a channel 7 for a recording signal to which the signal for recording is transmitted, a channel 801 for a reproducing signal to which an output signal for the magnetic head for reproduction selected only at the time of reproduction is transmitted, and a channel 802 for the reproducing signal selected at the time of recording and reproducing. At the time of the recording, an output buffer circuit 18 for a reproducing amplifier 401, to which the output signal from the magnetic head for the reproduction selected only at the time of the reproduction is transmitted, is turned off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotary magnetic head type recording / reproducing apparatus in which a plurality of recording heads, a reproducing head, and a recording / reproducing integrated circuit are mounted on a rotating drum and a multi-channel signal is transmitted by a rotary transformer.

  In recent years, in a rotary head type high-density recording / reproducing apparatus using a magnetic tape, there is a tendency to increase the total number of recording heads and reproducing heads mounted on a rotary drum in order to achieve a high transfer rate. For the purpose of increasing the capacity, a method of increasing the linear recording density by using a magnetoresistive head (hereinafter referred to as MR head) has been studied.

  Since an MR head detects a magnetic information signal input from a magnetic tape or magnetic disk as a recording medium by a resistance change, it is necessary to supply a detection current (sense current). Further, since this resistance change has non-linear characteristics with respect to the input magnetic field, a bias current is required to control the operating point of the MR head to a region with good linearity. Recent MR heads are designed to use these currents together (hereinafter referred to as a bias current).

  MR heads having high sensitivity characteristics are widely used in high-density magnetic recording / reproducing devices represented by hard disk devices and linear drive tape devices. However, in rotating head type magnetic recording / reproducing devices, Since the MR head to be mounted needs to be supplied and controlled with a bias current, it has not been put into practical use yet.

  Regarding power supply to the rotating side, a method of performing power transmission by a power transformer provided in a rotary transformer constituted by a plurality of channels has been adopted. However, since the power transformer is disposed close to the signal transformer, there arises a problem that power switching noise due to large amplitude switching jumps into a channel that performs weak signal transmission and deteriorates the error rate of the system. Therefore, a short ring is inserted between the rotary transformers to reduce crosstalk from the power rotary transformer to the signal rotary transformer (see, for example, Patent Document 1).

JP 10-2333013 (pages 6-7, FIG. 7)

  On the other hand, in order to increase the number of channels of the head in order to increase the transfer rate, it is necessary to increase the number of grooves (number of channels) of the rotary transformer to be used. In this case, a sufficient distance between the channels can be secured. The increase in crosstalk between channels in the signal rotary transformer becomes a problem. In particular, in a rotary head type magnetic recording / reproducing apparatus having a simultaneous recording / reproducing function such as a tape streamer apparatus, a recording signal and a reproducing signal are simultaneously transmitted through a rotary transformer. Alternatively, there is a possibility that the reproduction signal of one channel jumps into the reproduction signal of another channel and deteriorates the error rate of the system. In order to reduce this crosstalk, the short ring described above is inserted between each channel, but since the rotary transformer is built in the rotating drum, both the outer diameter and inner diameter are limited, the number of transmission channels increases, and the necessary short circuit Production becomes more difficult as the number of rings increases.

  An object of the present invention is to provide a rotary magnetic head type device that can increase the number of channels in a rotary transformer mounted on a rotary drum without increasing signal crosstalk.

  To achieve the above object, a rotary magnetic head type recording / reproducing apparatus of the present invention comprises a recording magnetic head, a first reproducing magnetic head, a second reproducing magnetic head, and the first and second reproducing magnetic heads. A rotary drum equipped with first and second reproduction amplification circuits for amplifying the head output signals respectively, and a rotary transformer for signal transmission between the rotary drums, and recording signals with the recording magnetic head In addition, a recording mode in which the recorded signal is immediately reproduced by the first reproducing magnetic head, and a reproduction in which the signal is reproduced from the recorded magnetic tape by the first and second reproducing magnetic heads. Mode. The rotary transformer transmits a recording channel for transmitting a signal to the recording magnetic head and a reproduction signal obtained by amplifying an output signal of the first reproducing magnetic head by the first reproduction amplifier circuit. 1 reproduction channel and a second reproduction channel for transmitting a reproduction signal obtained by amplifying the output signal of the second reproduction magnetic head by the second reproduction amplifier circuit. In the recording mode, the operation of the second reproducing amplifier circuit that amplifies the output signal of the second reproducing magnetic head is turned off.

  The second reproduction amplifier circuit is composed of a preamplifier circuit and an output buffer circuit, and the operation of the output buffer circuit is turned off in the recording mode.

  In the recording mode, the second reproduction channel for transmitting the output signal of the second reproduction magnetic head is electrically short-circuited.

  The rotary transformer is arranged so that the recording channel and the first reproduction channel are not adjacent to each other.

  In the rotary transformer, the second reproduction channel is disposed between the recording channel and the first reproduction channel.

  According to the present invention, it is possible to provide a rotary magnetic head type recording / reproducing apparatus that can suitably cope with a multi-channel configuration.

  Hereinafter, each example of the present invention is described in detail.

  FIG. 1 is a block diagram showing an embodiment of a rotary magnetic head type recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a rotating drum, which includes recording heads 201 and 202, MR heads 301 to 304, recording / reproducing integrated circuits 401 and 402, an oscillation circuit 5, a decoder circuit 6, an output buffer circuit 18, and a power supply circuit 16. Is installed. A rotary transformer 20 has a recording signal channel 7, reproduction signal channels 801 and 802, a control signal channel 12, a power channel 15, and short rings 171 to 174. On the fixed side, a recording data generation circuit 11, reproduction system signal processing circuits 101 and 102, buffer amplifiers 91 and 92, a control data generation circuit 13, and a power signal generation circuit 14 are provided.

  Two MR heads 301 and 302 and two MR heads 303 and 304 are mounted on the rotating drum 1 so as to face each other at 180 °, and are attached to a magnetic tape (not shown) wound approximately 180 ° in the drum rotating direction. Read the recorded signal. The recording head includes a recording head 201 having an azimuth angle + Az and a recording head 202 having an azimuth angle−Az that are opposed to each other by 180 °. Further, the recording head 201, the recording head 202, The MR heads 303 and 304 are arranged at intervals of 90 °.

  FIG. 2 shows an example of the head arrangement as seen from the tape sliding surface side of the MR head used in this embodiment. In FIG. 2, two MR heads 301 and 302 are arranged in two rows given an azimuth angle + Az, and similarly two MR heads 303 and 304 are arranged in two rows given an azimuth angle -Az. In addition, it has a two-layer multi-gap (multi-track head) structure (hereinafter, a plurality of heads configured on one chip is referred to as a head assembly).

  Since the two MR heads 301 and 302 formed on one chip by the thin film process are arranged at close positions of several tens μm to several hundreds μm, the MR element depth (MR height) is set equal. Both heads can have almost the same magnetic characteristics. The same applies to the head assembly including the MR heads 303 and 304.

  FIG. 3 shows an example of the head arrangement as viewed from the tape sliding surface of the recording head used in this embodiment. 3 is produced by a thin film process, the recording head 201 is given an azimuth angle + Az, and the recording head 202 is given an azimuth angle -Az.

  In this configuration, the power supply circuit 16 is provided on the rotating drum 1 so that circuit components such as the recording / reproducing integrated circuits 401 and 402 and the decoder circuit 6 are mounted on the rotating side. The power supply circuit 16 includes a rectifier circuit and a voltage stabilization circuit, and performs an operation of obtaining a desired DC voltage from the output AC signal of the power signal generation circuit 14 transmitted through the power channel 15.

  In FIG. 1, recording / reproducing integrated circuits 401 and 402 each include a two-channel recording circuit and a two-channel reproducing amplifier for the MR head, and are for Data, Clock, CS (Chip select), and R / W (recording / reproduction switching). The operation mode is controlled by four control lines. The control functions include, for example, a head (amplifier) changeover switch, MR head bias current setting, reproduction amplifier gain setting, MR head-specific thermal asperity noise (TA) detection, correction, and recording current value setting. First, a register corresponding to the function is selected, control data is written, and its operation state and value are determined.

  These control data are generated by the control data generation circuit 13 and transmitted to the decoder circuit 6 through the control signal channel 12. The decoder circuit 6 again generates control data for the recording / reproducing integrated circuits 401 and 402 for this information data, and controls it by the above four types of control lines. These data output signals are generated by the oscillation clock of the oscillation circuit 5 connected to the decoder circuit 6. The oscillation frequency of the oscillation circuit 5 varies depending on the type and number of the recording / reproducing integrated circuits 401 and 402 to be used, but approximately 20 to 40 MHz is selected. With this configuration, the bias current value of each of the MR heads 301 to 304 mounted on the rotary drum 1 can be varied and adjusted independently from each fixed head. Similarly, the recording current values of the recording heads 201 to 202 can be varied and adjusted from the fixed side.

  At the time of recording, the data signal output from the recording data generation circuit 11 passes through the recording data channel 7 and the R / W line, and the recording / reproducing integrated circuit 401 set in the recording mode and the recording heads 201 and 202 add + azimuth. , Azimuth data tracks are recorded on the magnetic tape. At this time, the MR head 302 immediately reproduces the + azimuth data track recorded by the recording head 201 and the MR head 304 reproduces the −azimuth data track recorded by the recording head 202, thereby improving the reliability of the recorded data (check (After-light function). Therefore, the head heights of the MR heads 302 and 304 are adjusted with respect to the recording heads 201 and 202, and the recording / reproducing integrated circuit 402 is always set to the reproducing mode. The example in which the MR heads 302 and 304 are used as MR heads for simultaneous reproduction has been described above, but this may be a combination of the MR heads 301 and 303. In this case, the MR heads 302 and 304 may be connected to the recording / reproducing integrated circuit 401, and the MR heads 301 and 303 may be connected to the recording / reproducing integrated circuit 402.

  At the time of reproduction, the recording / reproduction integrated circuit 401 is set to the reproduction mode by the R / W line. Since the head assemblies of the MR heads 301 and 302 and 303 and 304 are provided at 180 ° facing positions, signals reproduced from the MR heads 301 (+ Az azimuth) and 303 (−Az azimuth) are output every 180 °. The signals are alternately amplified by the recording / reproducing integrated circuit 401, passed through the output buffer circuit 18, and transmitted to the fixed buffer amplifier 91 and the reproduction system signal processing circuit 101 via the reproduction signal channel 801. At the same time, signals reproduced from the MR heads 302 (+ Az azimuth) and 304 (−Az azimuth) are transmitted to the recording / reproducing integrated circuit 402, the reproduction signal channel 802, the buffer amplifier 92, and the reproduction system signal processing circuit 102. The buffer amplifiers 91 and 92 are constituted by a low input impedance circuit such as a base ground circuit.

  At the time of this reproduction, the tape speed is set slightly lower than the tape feeding speed at the time of recording (for example, about 0.95 times), and the mutual heads of the MR heads 301, 302 and 303, 304 shown in FIG. By setting the height adjustment value to be equivalent to one track pitch and selecting the track width B of the MR head to be 1.2 to 1.5 times the track pitch, no special tracking control is required, and all recorded data Can be read using four MR heads (hereinafter, this reproducing method is referred to as a non-tracking method). For this purpose, four MR heads 301 to 304 are required for two recording heads 201 and 202.

  FIG. 4 shows an example of the structure of the rotary transformer used in this embodiment. 7 is a recording data channel, 801 and 802 are reproduction signal channels, 12 is a control signal channel, 15 is a power channel, and 171 to 174 are short rings.

  In this embodiment, at the time of recording, the MR heads 302 and 304 for check after write reproduction operate simultaneously with the recording heads 201 and 202 as described above. Therefore, the recording channel 7 and the reproduction signal channel 802 corresponding to these signal transmissions are arranged so as not to be adjacent to each other in order to prevent mutual signal crosstalk.

  On the other hand, since the MR heads 301 and 302 and the MR heads 303 and 304 operate simultaneously by the non-tracking method described above during reproduction, the reproduction signal channels 801 and 802 corresponding to these signal transmissions are not adjacent to each other. Deploy.

  For example, if a rotary drum with a diameter of 47 mm is considered, the outer diameter allowed for the rotary transformer is about 40 mm, and there are 1 system for recording data, 2 systems for reproduction signal, 1 system each for power supply and control signal, 5 systems in total. In this embodiment, the rotary transformers are arranged as shown in FIGS. 1 and 4. That is, in the rotary transformer 20, a recording signal channel 7 that does not operate simultaneously at the time of check-after-write and a channel 801 that transmits the output signals of the MR heads 301 and 303 that operate only at the time of reproduction are disposed adjacent to each other. In addition, the reproduction signal channel 802 of the MR heads 302 and 304 operating at the time of check after write is arranged on the innermost circumference so as to be separated from the recording signal channel 7 and between the reproduction signal channel 801 operating simultaneously at the time of reproduction. A short ring 171 was provided. In addition, the control signal channel 12 and the power channel 15 that are always operated simultaneously are provided on the outer peripheral side, the short rings 172 and 173 are provided between the respective channels, and the power supply switching noise is shorted so as not to leak outside the rotary transformer 20. A ring 174 was placed.

  With this configuration, even with a total of 6 heads, there is less crosstalk between channels, the number of short rings inserted between channels can be reduced to 4, and the total number of grooves can be reduced to 9. Can be realized.

  As described above, in this embodiment, the reproduction signal channels 801 and 802 transmit reproduction signals having a signal level of about 200 to 500 mVp-p at the time of reproduction, so that a short ring 171 is provided between the two channels for reproduction. Crosstalk between signals is reduced. Normally, a rotary transformer with an outer diameter of about 40 mm can provide attenuation of 5 to 8 dB in a low frequency region of 10 MHz or less and 15 dB in a high frequency region when the short ring 171 is not provided. Attenuation of 60 to 70 dB in the frequency domain and 35 dB to 40 dB in the high frequency domain, that is, a 35 dB D / U (Desire / Undesire) ratio can be obtained.

  Next, the operation during check after write will be described. The recording / reproducing integrated circuit 401 is set to the recording mode, and supplies a recording current corresponding to the recording data transmitted through the recording signal channel 7 to the recording heads 201 and 202. At this time, the recording amplifier in the recording / reproducing integrated circuit 401 has crosstalk of the recording signal, and the output buffer circuit 18 of the reproducing amplifier generates a large amplitude crosstalk signal determined by the dynamic range of the reproducing amplifier. In general, since the output dynamic range of the recording / reproducing integrated circuit 401 is designed to be about 2 Vp-p, the reproduction signal channel 801 is inputted with an unnecessary signal four times (+12 dB) as normal, and the reproduction signal channel 802. The D / U ratio of the worst is about 23 dB, and the error rate may deteriorate.

  Therefore, as shown in FIG. 1, in this embodiment, the output buffer circuit 18 in the recording / reproducing integrated circuit 401 is controlled to be turned off by the operations of the control data generating circuit 13 and the decoder circuit 6 at the time of check after write. By preventing unnecessary signals from being input to the channel 801, crosstalk to the reproduction signal channel 802 is reduced. This operation is basically achieved by turning off the power supply of the output buffer circuit 18, and the control data generating circuit 13 and the decoder circuit 6 turn off the power supply unit of the output buffer circuit 18 only at the time of check after write and reproduce the data. It is controlled to turn on the power supply unit at the time of time, fast forward and rewind of the tape.

  As described above, according to this embodiment, it is possible to reduce the crosstalk signal level with respect to the reproduction signal level at the time of check after write, and to prevent the system error rate from deteriorating.

  FIG. 5 is a partial block diagram showing another embodiment of the rotary magnetic head type recording / reproducing apparatus according to the present invention. This embodiment shows an example in which the power supply unit of the output buffer circuit 18 of the recording / reproducing integrated circuit 401 cannot be turned off from outside. In FIG. 5, 19 is a voltage-current conversion circuit, 21 and 22 are switch circuits, 23 ˜27 are resistors, and 28 and 29 are transistors. A voltage / current conversion circuit 19 formed of a differential amplifier including resistors 23 to 27 and transistors 28 and 29 converts the output voltage of the output buffer circuit 18 of the recording / reproducing integrated circuit 401 into a current, and is used for a reproduction signal in the subsequent stage. Channel 801 is current driven. Here, when the power supply unit of the output buffer circuit 18 of the recording / reproducing integrated circuit 401 cannot be turned off by an external signal at the time of check after write, the amplitude of the reproduction signal channel 801 is not determined by the transformer inductance and the supply current of the voltage / current conversion circuit 19. A signal will be generated. Therefore, in this embodiment, the switch circuits 21 and 22 are controlled by the output signal of the decoder circuit 6 to turn on / off the power supply of the voltage / current conversion circuit 19, and the switch circuits 21 and 22 are opened at the time of check-after-write. The conversion circuit 19 was not supplied with power. As a result, the leakage signal in the recording / reproducing integrated circuit 401 can be prevented from being transmitted through the reproduction signal channel 801. According to this embodiment, the necessary D / U ratio of the signal transmitted through the reproduction signal channel 802 can be secured by the effect of the short ring 171 without increasing the crosstalk signal.

  In FIG. 5, if the output of the output buffer circuit 18 of the recording / reproducing integrated circuit 401 can be controlled to be off, the switch circuits 21 and 22 are unnecessary, but the voltage-current conversion circuit 19 is directly used as a driving circuit for the reproduction signal channel 801. May be used.

  FIG. 6 is a block diagram showing another embodiment of the rotary magnetic head type recording / reproducing apparatus according to the present invention. In FIG. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals, 30 and 31 are switch circuits, and 32 is a system control circuit. In FIG. 6, the switch circuits 30 and 31 are provided on the fixed side of the reproduction signal channel 801, and the switch circuits 30 and 31 are turned on during the check after write to electrically short the reproduction signal channel 801. As a result, the reproduction signal channel 801 has a short ring effect, and crosstalk from the recording data channel 7 to the reproduction signal channel 802 is further reduced. As another effect, the recording data channel 7 is sandwiched between the shorted reproduction signal channel 801 and the short ring 172 at the time of check after write, so that the inductance is reduced and the high frequency region in recording data transmission is reduced. The characteristics can be improved. The operations of these switch circuits 30 and 31 are controlled by a system control circuit 32. In the embodiment shown in FIG. 6, the switch circuits 30 and 31 are provided on the fixed side of the reproduction signal channel 801. However, this may be provided on the rotation side. In this case, the switch circuits 30 and 31 may be controlled by the output signal of the decoder circuit 6.

  Although the rotary transformer has been described above as a flat type, it may be a coaxial type. Further, the recording head is described as a thin film head and the reproducing head is described as an MR head. However, these may be applied to embodiments using conventional coil heads.

  As described above, the output buffer circuit off control, the rotary transformer channel arrangement, and the channel shorting method according to the present embodiment can reduce the crosstalk between channels even in a device with an increased number of heads, and can minimize the number of short rings inserted between channels. Therefore, it is possible to reduce the size and cost of the apparatus.

1 is a block diagram showing an embodiment of a rotary magnetic head type recording / reproducing apparatus according to the present invention. FIG. 2 is a diagram showing an example of the head arrangement of the MR head in FIG. 1. FIG. 2 is a diagram illustrating an example of a head arrangement of a recording head in FIG. The figure which shows an example of the structure of the rotary transformer in FIG. FIG. 6 is a partial block diagram showing another embodiment of a rotary magnetic head type recording / reproducing apparatus according to the present invention. The block diagram which shows the other Example of the rotating magnetic head type recording / reproducing apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotary drum, 201, 202 ... Recording head, 301-304 ... MR head, 401, 402 ... Recording / reproducing integrated circuit, 5 ... Oscillator circuit, 6 ... Decoder circuit, 7 ... Recording data channel, 801, 802 ... Reproducing Signal channel 91, 92 Buffer amplifier 101, 102 Reproduction system signal processing circuit 11 Recording data generation circuit 12 Control signal channel 13 Control data generation circuit 14 Power signal generation circuit 15 DESCRIPTION OF SYMBOLS ... Power channel, 16 ... Power supply circuit, 171-174 ... Short ring, 18 ... Output buffer circuit, 19 ... Voltage current conversion circuit, 20 ... Rotary transformer, 21, 22 ... Switch circuit, 23-27 ... Resistance, 28, 29 ... transistor, 30, 31 ... switch circuit, 32 ... system control circuit.

Claims (5)

Equipped with a recording magnetic head, a first reproducing magnetic head, a second reproducing magnetic head, and first and second reproducing amplifier circuits for amplifying the output signals of the first and second reproducing magnetic heads, respectively. In a rotary magnetic head type recording / reproducing apparatus that includes a rotary drum and a rotary transformer that performs signal transmission between the rotary drum and performs signal recording / reproduction on a magnetic tape,
A recording mode in which a signal is recorded by the recording magnetic head and the recorded signal is immediately reproduced by the first reproducing magnetic head, and the first and second reproductions from the recorded magnetic tape. A reproduction mode for reproducing a signal with a magnetic head for use,
The rotary transformer transmits a recording channel for transmitting a signal to the recording magnetic head and a reproduction signal obtained by amplifying an output signal of the first reproducing magnetic head by the first reproduction amplifier circuit. 1 reproduction channel, and a second reproduction channel for transmitting a reproduction signal obtained by amplifying the output signal of the second reproduction magnetic head by the second reproduction amplifier circuit,
In the recording mode, the operation of the second reproducing amplifier circuit for amplifying the output signal of the second reproducing magnetic head is turned off. The rotary magnetic head type recording / reproducing apparatus according to claim 1,
The second reproduction amplifier circuit includes a preamplifier circuit and an output buffer circuit,
In the recording mode, the rotating magnetic head type recording / reproducing apparatus is characterized in that the operation of the output buffer circuit is turned off. The rotary magnetic head type recording / reproducing apparatus according to claim 1 or 2,
The rotary magnetic head type recording / reproducing apparatus characterized in that, in the recording mode, the second reproducing channel for transmitting the output signal of the second reproducing magnetic head is electrically short-circuited. The rotary magnetic head type recording / reproducing apparatus according to any one of claims 1 to 3,
The rotary magnetic head type recording / reproducing apparatus, wherein the rotary transformer is arranged so that the recording channel and the first reproduction channel are not adjacent to each other. The rotary magnetic head type recording / reproducing apparatus according to any one of claims 1 to 3,
The rotary magnetic head type recording / reproducing apparatus, wherein the rotary transformer has the second reproduction channel disposed between the recording channel and the first reproduction channel.

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