JPH0246505A - Digital multi-element magnetic head - Google Patents

Abstract

PURPOSE:To decrease the number of parts, to reduce the energy consumption and to execute the miniaturization by varying the number of windings of ring element magnetic heads arranged at a prescribed interval, setting the size of a signal to a prescribed value and synthesizing these signals. CONSTITUTION:Plural ring element magnetic heads 1a-1d, in which a head width is the same, are provided and a means 10 to arrange ring element magnetic heads 1a-1d in a track direction at a prescribed interval, make respectively different the number of windings of these ring element magnetic heads 1a-1d, set the size of the signal to a prescribed value, and synthesize these signals is provided. Namely, the data pattern recorded to the track of a medium is reproduced by the ring element magnetic heads 1a-1d, a prescribed time delay is generated to the reproducing output signal of respective ring element magnetic heads 1a-1d by the relative speed with the head and medium and the relative interval of the ring element magnetic heads 1a-1d, further, the size of the signal from the ring element magnetic heads 1a-1d is set by the number of windings beforehand and synthesized. Thus, with simple constirution, a waveform equalizing function can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in digital magnetic recording and reproduction, etc., and is applied to a digital multi-element magnetic head that has a waveform equalization effect on its own.

Conventional technology In recent years, DAT (digital audio tape recorder)
Devices that perform high-density digital magnetic recording, including , have been put into practical use. Conventional magnetic heads used in these devices have a single gap for one track.

FIG. 8 shows a digital data reproducing circuit using a conventional magnetic head.
The head 100 reads out the signal recorded on the amplifier 2.
After being amplified by the waveform equalization circuit 3, the data is
- The equalized signal is input to the amplifier circuit 4. In recording and reproducing such digital data, various modulation methods are used to make effective use of the required band and time interval accuracy, but the non-distortion condition for the reproduced waveform is given by the Nyquist standard. Therefore, a waveform equalization circuit is used that shapes the distorted output waveform read from the recording medium and reproduces digital data.

A transversal filter is a circuit often used as this waveform equalization circuit. FIG. 9 shows an example of a waveform equalization circuit using a 4-tap transversal filter.

3 to 7 In FIG. 9, 30'l is an input terminal, 3'l, 32 and 33 are delay elements, 34 to 37 are coefficient circuits, 38 is an adder circuit, and 302 is an output terminal. The operation will be explained below with reference to FIG.

A signal reproduced from a recording medium and amplified to a predetermined level is input to the input terminal 301 . This signal is input to delay element 31 and sequentially input to delay elements 32 and 33. Here, if the amplitude of the input signal is ω, and the delay amount of the delay element is fT, then the input signal fAeXI)
It can be expressed as (jor(t+3T/2)). The output signal of each tap can be expressed as follows using this input signal.

Input of coefficient circuit 34 Aexp(jw(t+3T/2
)) Input of coefficient circuit 35 Aexp(jw(t+T/
2)) Input of coefficient circuit 36 Aexp (j ω(t
-T/2) ) Input of coefficient circuit 37 Aexp(jw
(t-3T/2)) Therefore, the coefficient -4 of each multiplier circuit is 1.
2. 3. 4, the output of the adder circuit 38 is 302
is 2+9 for A[Klexp(jθ](t+3T/2))+
xp(jw(t+T/2))+to 3exp(j ω(
4exp (j ω(t-, 3T/
2))]. Here, for example, 22, 3=, and 1=
4=P-, the output of the adder circuit 6 is 2-A--(cos (ωT/2)+P-cos (
3o)T/2) ) ・exp (koo)t) becomes,
A linear phase characteristic can be obtained.

In this way, the waveform equalization circuit is used to adjust the recording and reproduction characteristics to obtain a distortion-free condition that satisfies the Nyquis 1- standard.

Problems to be Solved by the Invention However, the conventional configuration described above requires a waveform equalization circuit, which increases the number of parts, increases power consumption, and increases the size.

In view of the above, an object of the present invention is to provide a digital multi-element magnetic head having a waveform equalization function with a simple configuration.

Means for Solving the Problems In order to achieve the above object, the present invention has a plurality of ring-shaped element magnetic heads having the same head width, and the ring-shaped element magnetic heads are arranged at predetermined intervals in the 1-to-1 direction. The number of windings of these ring-shaped magnetic elements is set to a predetermined value by setting the magnitude of the signal to a predetermined value, and the structure includes means for synthesizing these signals.

According to the above-described structure, the present invention reproduces the data pattern recorded on the track of the medium with each ring-shaped element magnetic head arranged at a predetermined interval in the track direction, so that the relationship between the head and the medium is A predetermined time delay can be caused in the reproduced output signal of each ring-shaped element magnetic head by the relative speed and the relative spacing of the ring-shaped element magnetic heads, and the magnitude of the signal from these ring-shaped element magnetic heads can be expressed by the number of turns. A waveform equalization effect can be obtained by setting them in advance and composing them.

Embodiment FIG. 2 is a diagram showing the structure of a digital multi-element magnetic head according to an embodiment of the present invention, and shows the mechanical structure of four ring-shaped element magnetic heads 1a, 1b, 1c, and 1d. In FIG. 2, numeral 9 indicates recording ranks 1 to 1 on the magnetic recording medium, and the ring-shaped element magnetic head 1 is moved on the tracks 6 and \7 in the direction of the arrow. Ring-shaped element magnetic heads 1h, 1b.

The head width of the 1C21d is W, which is the same. This allows the output signal of each element magnetic head to increase or decrease evenly even if the head slightly deviates from the track, thereby making it possible to reduce fluctuations due to tracking deviation. Further, the relative positions of the heads in the trunk direction are spaced apart by a distance S.

FIG. 3 is a diagram showing the configuration of a digital multi-element magnetic head according to another embodiment of the present invention, and shows the arrangement of a ring-shaped element magnetic head in the case of having an azimuth angle.

Assuming that the relative speed between the head and the medium is 'Iv', a relative delay time of S/V can be obtained between the heads.

If the shortest recording wavelength is λ, the shortest period 'rw is Tw=λ/
It becomes V. Current interval 3 fan 1/2 of shortest recording wavelength λ
Then, the delay time T is T=TW/2.

The output signals of each head, each having a delay time of T, are obtained by multiplying by a coefficient according to the number of turns of the head. It is possible to obtain the effect of

FIG. 1 shows the electrical configuration of an example of the digital multi-element magnetic head of the present invention. Output signals from four ring-shaped element magnetic heads 1a, 1b, 1c, and 1d are added and subtracted by a combining circuit 10. The signals are combined and taken out as an output signal from terminals 100 and 101.

FIG. 4 is a diagram showing a combination circuit that connects the individual magnetic heads in series. El
a, Elb, Elc, and Eld, the output signals of the digital multi-element magnetic head 1 are output from the output terminals 101 and 10.
The combined output signal E101 is output between 0 and 0, and the combined output signal E101 is as follows.

Flol--E12L+E1b+E1C-Ela Therefore, since the polarity can be selected, each tap coefficient can be arbitrarily designed by changing the number of turns of the ring-shaped element magnetic head.

Similarly, FIG. 5 is a circuit diagram of a digital multi-element magnetic head according to the present invention, which is a composite circuit in which each element magnetic head is connected in parallel with selected polarity. The desired value can be obtained by

FIG. 6 shows an example of a digital data reproducing apparatus using the digital multi-element magnetic head of the present invention.

In FIG. 6, reference numeral 1 designates the digital multi-element magnetic head of this embodiment, and the reproduced output signal is amplified by an amplifier 2 and applied to a Demes 1-rope circuit 4.

The data strobe circuit 4 extracts a clock from a self-clocking signal and reproduces data.

A phase-locked loop circuit is used to extract the clock.

As is clear from FIG. 6, this embodiment can omit the waveform equalization circuit that was conventionally necessary.

FIG. 7 is a block diagram of a data reproducing apparatus in which the output of a digital multi-element magnetic head using a ring-shaped element magnetic head is taken out via a rotary transformer. In FIG. 7, 6 is a rotary transformer. Since the ring-type element magnetic head outputs a differential response, the amplifier 2 also has an integral function. In this case, linearity is maintained between combining the output signals of the 9-7 element magnetic heads in advance and then integrating them, and integrating the output signals of each element magnetic head and then combining them. It's exactly the same. By synthesizing the output signals of the element magnetic heads in advance in this manner, there is an advantage that the number of rotary transformers for signal transmission can be reduced when a digital multi-element magnetic head is mounted on a rotary cylinder. As is clear from FIG. 7, the waveform equalization circuit that was conventionally required can be omitted.

Note that the number of turns and the spacing S of each element magnetic head are determined based on constants obtained by designing a transversal filter.

Further, in this embodiment, the distance S is set to be the same value between each element magnetic head, but the distance S may be set to be different between each element magnetic head.

Furthermore, in this embodiment, the number of element magnetic heads is four, but any integer greater than or equal to two may be used, and it is left to the degree of freedom of the design, similar to the number of taps of the transversal filter. Needless to say, 10 ・＼.

Nor.

Effects of the Invention As described above, according to the present invention, the data pattern recorded on the track of the medium is reproduced by each ring-shaped element magnetic head arranged at a predetermined interval in the direction of the track. A predetermined time delay can be caused in the reproduced output signal of each element magnetic head depending on the relative speed between the head and the medium and the relative spacing between the element magnetic heads.
Since the magnitude of the output signal can be set in advance by the number of turns of the ring-shaped element magnetic head, a waveform equalization effect can be obtained by combining the signals from these element magnetic heads. Therefore, it is possible to obtain a waveform equalization effect with a linear phase characteristic with a single head, and the Nyquis l-
By setting the standard k x plus no distortion, it is possible to eliminate the waveform equalization circuit that was conventionally necessary, and it is possible to reduce the number of parts, reduce power consumption, and downsize.

Furthermore, by synthesizing the output signals of the element magnetic heads in advance, there is an advantage that when a digital multi-element magnetic head is mounted on a rotating cylinder, the number of rotary transformers for signal transmission can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a signal connection diagram in a digital multi-element magnetic head according to an embodiment of the present invention, FIGS. 2 and 3 are element magnetic head arrangement diagrams in a digital multi-element magnetic head, and FIG.
6 is a wiring diagram showing an example of a circuit for synthesizing reproduction output signals of a digital multi-element magnetic head of the present invention, and FIG. 6 is a wiring diagram showing another example of a circuit for synthesizing reproduction output signals of a digital multi-element magnetic head of the present invention. 6 is a block diagram of a digital data reproducing apparatus using the digital multi-element magnetic head of the present invention, and FIG. 7 is a block diagram of a digital data reproducing apparatus using the digital multi-element magnetic head of the present invention. FIG. 8 is a block diagram of a digital data reproducing apparatus using a conventional magnetic head, and FIG. 9 is a block diagram of a waveform equalization circuit used in a digital data reproducing apparatus using a conventional magnetic head. 1...Head, 1fL, 1b, IC, 1d...Ring type element magnetic head, 2...Amplifier, 3
゛...Waveform equalization circuit, 4...Datas)
o-b circuit, 6...rotary transformer, 9.
...Magnetic medium, 10...Synthesis circuit, 31,
32.33...Delay element, 34.35.36.3
7... Coefficient circuit, 38... Addition circuit. Name of agent: Patent attorney Shigetaka Awano.

Claims (1)

[Claims] It has a plurality of ring-shaped element magnetic heads with the same head width, and the ring-shaped element magnetic heads are arranged at a predetermined interval in the track direction, and the number of turns of these ring-shaped element magnetic heads is made different so that signals can be transmitted. A digital multi-element magnetic head characterized by comprising means for setting the magnitude to a predetermined value and for synthesizing these signals.