DE1907688A1 - Method and arrangement for recording data - Google Patents

Description

our reference: P 2011

SHE PIESSEY COMPANY LIMITED

56 Vicarage Lane, Ilford, Essex / England

Method and arrangement for recording data

Schw / Ba

The invention relates to a method and an arrangement ' for recording data. In particular, it relates to the discontinuous recording of data on magnetic tape in the technique of step-by-step recording, but it can also apply to the continuous writing of data can be used at a relatively low speed. ·

The invention also relates to a method for recording a signal on a magnetic tape by means of a write head. Immediately after the recording, the tape is guided over a read head, and one removed from this read head Signal is compared to the signal that should be recorded. With the help of the procedure it becomes so continuously checked whether the writing of a required signal has been carried out exactly.

If the technique of step-by-step recording is used, then the invention can also provide a method for Control of the length of each recording step can be provided which can be useful where control is not is included in the construction of the indexing device for the tape. The end point of each recording step can refer to the 3e

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Wise controlled without one having to achieve this. Effect requires its own electronic arrangement.

In the method according to the invention, the test is carried out whether a predetermined signal has been recorded on a magnetic tape by having the signal on the Tape is recorded while the tape is stationary or moving at a relatively low speed, that the described tape section is guided past the read head, and that the output signal of the read head with the predetermined signal is compared to determine whether the signal has been properly written on the tape is.

When used in a step-by-step recording device, the bypassing of the described Tape section on the read head by the normal movement of the tape in front of a 'write head from a step position to the other.

The invention also includes a tape head having a write nip and a read nip for performing the above. Procedure. Dei ¹ distance between the write gap and the read gap can be very small, for example, only a few thousandths of a centimeter or possibly only 0.0013 cm (0.0005 inch). This distance is expediently on the order of 5 or 7.5 thousandths of a centimeter (2 or 3 thousandths of an inch). If the tape head is to be used in an intermittent recording device, the reading gap can be spaced from the writing gap by a distance which can be smaller than the spacing between adjacent data sections on the tape. A magnetic circuit that includes a reading gap preferably also has a secondary gap to increase the magnetic resistance of the reading flux path to the writing flux induced therein by the writing signals.

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An embodiment of the invention is shown in the drawing shown. Show in it:

: Pig.1 a view of a tape head for data recording with two columns according to the invention,

Pig.2 is a view of the top of the tape head according to Pig.1 without an inserted magnetic tape,

3 shows a block diagram to explain the inventive Procedure of reading after writing and

Pig.4 occurring at different points in the circuit of Pig.3 Signal fora.

The embodiment of the invention now to be described is intended for a step-by-step recording device that works according to the HRZl system (with constant Saturation for the binary value "! TuIl" and a change the saturation direction for the binary value "one"). The built-up tape head is for multi-track recording digital data and it can be used to record nine separate channels across the width of the tape will. The Banäkopf enables the information recorded on the tape to be read out with each character writing step to check for an exact record.

The tape head 1 has a writing leg 2 and a Reading leg 3 · Together with a middle leg 4, these form a writing gap 5 and a reading gap 6. Around the A write winding 7 and a read winding 8 are attached to each leg. To carry out a reading or During the writing process, part of the tape 9 held against the tape head 1 can move in the direction of the arrow 10 move across the columns of the tape head. The middle leg 4 of the tape head is narrow because it is thinner than the

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Is the distance between the digits to be recorded on the tape. In this embodiment, the center leg has a width of 0.075 cm (0.003 inch). A section of the tape moves as it slides past Tape head first across the write gap 5, whereupon the tape stops where a signal is recorded on it shall be. Subsequently, the BSnd for the The next signal to be recorded on the associated tape section is then moved on. Before that. If the tape is stopped again so that the writing of the second signal is possible, the first slides written signal carrying point across the reading gap 6, and while the tape section written moves, the reading gap detects the signal written first on the tape. With the help of a Circuit is this signal with that signal ♦ ' that is intended to be recorded on the tape. · Was. This way there is a continuous review which ensures that no errors or gaps occur during the write process.

The reading gap 6 is narrower than the writing gap 5. If the magnetic circuits containing the writing and reading gaps lie next to each other, one could expect that the magnetic flux through the writing gap during the writing process could also flow in the magnetic circuit of the reading gap, so that a during the read signal detectable during the reading process would thereby be covered. In order for this coupling effect is reduced between the Mqgnetkreisen-the read and write heads, the magnetic resistance of the reading circuit is increased by attaching a secondary gap 11 at the rear of L _e sekopfs. At the same time, the gap 40 on the back of the write head is reduced to the smallest possible extent.

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In Pig.2 is a top view of a trace of the head of the head of Fig.i shown, in which the tape 9 from the tape head is removed. The tape head is for eating track recording constructed of digital data. From this illustration it can be seen that each writing leg 2 is from a stack consists of writing lamellas 12, which have such a depth that they are q.uer over the entire width the writing trace extend. The reading handle is in this figure as a corresponding stack of reading slats 13 shown. The middle leg 4 is also shown '. It can be seen that the reading lamellas 13 have a Form stack that is narrower than the stack of writing blades 12, so that corresponding to that of the NRZI data recording system According to the usual practice, a wide writing gap and a narrow reading gap can be made possible.

The main ones are shown in a block diagram in Pig.3 Parts of an electronic recording and testing system for recording a channel on the recording tape shown.

The recording and testing system is for everyone else The tracks available on the recording tape are constructed in the same way, and there are no functional ones Interdependence of the tracks so that only the arrangement for one track is described.

A signal to be recorded on the tape is sent to a Terminal 14 is input to the circuit, from where it enters a memory 15, the e-s of a write input gate circuit 16 feeds. The write input gate circuit 16 becomes dependent on the state of the memory jo actuates that it allows pulses from a clock pulse generator to pass, the resulting output signal being sent to a bistable switch 18 is placed. The bistable switch

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is used to determine the current direction in a write winding of the tape head 1 via a write head driver amplifier 19. The write head driver amplifier 19, the bistable switch 18 and the write input gate circuit 16 illustrate conventional circuit arrangements used in normal tape recording using the NRZ1 system. ""

After the required signal applied to the H terminal is recorded on the tape, that tape is changed Moved a short step further so that a new section of tape is transported to the writing gap. The next Information bit can then be written. If the first bit of information written is during the When the tape moves past the reading gap 6, a signal is generated in the reading winding and a reading amplifier 20 fed. The sense amplifier 20 is designed to have a short desaturation time. The amplified output signal of sense amplifier 20 passes through a gate circuit 27 and is then sent to a full-wave rectifier 21 applied, the output signal of which is sufficient to operate a voltage level detector 22 “The output signal of the voltage level detector 22 next passes through a gate circuit 23 * a bistable switch 24, and a comparison circuit 25. The comparison circuit 25 compares that from the read winding of the tape head 1 signal detected on the tape with the contents of the memory 15 which is equal to the signal on the Tape should have been written. In order to ensure that the read amplifier 20 to the comparison circuit 25 ■ Guided signals are only generated on the basis of the beep signals derived from the tape head 1, are the gate circuits and 23 open only in the time segment in which a read pulse is expected. The gate switch pulse is generated by the clock pulse generator 17 via a delay element 28 and one

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Pulse shaper 29 is generated. Another gate switching pulse is generated by the pulse shaper -29 via a delay element 30 and a pulse shaper 31 derived. This further gate switching pulse is applied to a gate circuit 32, which is shown in open state scans the state of the comparison circuit and generates a signal 26 that the presence or indicates the absence of an error. If an error is found, the data can be rewritten or an appropriate error signal can be recorded as the next piece of information on the magnetic tape.

The operation of this circuit is related with Fig.4 described, in which the signal shapes occurring at different points in the circuit as a function from time T are shown. With the NRZ1 system (as already explained) brought the magnetic tape into a constant state of saturation for the binary value "zero", while reversing the direction of saturation for each binary value "one" recorded on the tape. In Fig.1A shows an input signal to be recorded on the tape which first corresponds to a "one" and then to "Zero" changes. FIG. 1B shows clock pulses with a constant frequency that are supplied by the clock pulse generator 17 will. The waveform of the write head current sent from the write head driver amplifier 19 to the write winding is shown in Fig. 4-0. It is closed recognize that the recording of binary values is "one" as a change in the direction of saturation on the tape occurs while no change of direction is made at the point where a "zero" is required to be recorded of the current supplied to the write head.

The data logger considered here is a step-by-step data logger, at that the writing takes place at the moment of the tape standstill while the recorded data is moving q_uer to the reading gap takes place in the time segments in which the tape is between the positions

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which it is stopped to record this information. The tape therefore moves jerkily across the tape head 1, and the speed of the tape movement could take place as shown in Figure 4D. To the through_ The tape comes to a standstill during a recording. For a short time the band is then at an essentially constant one Speed is accelerated and then braked again sharply to a standstill, thus another data section can be applied to the tape, D * as reading the dem Information supplied to the tape takes place during the tape movement, and the tension generated in the reading winding 8 could correspond to the signal form shown in Pig.4E. · ■ The read winding 8 becomes considerable from the write process affects because the magnetic circuits for writing and reading are still tightly coupled, though the secondary gap 11 in the magnetic circuit of the reading gap placed in the reading flux path to increase the magnetic resistance. The writing process therefore causes the occurrence of a serious spurious effect 35 in the waveform of the read head voltage. Another - serious one Disruptive effect 33 can be caused by the actuation of the brake, which stops the tape "in the event a step-by-step recorder is used. A required useful signal 34 must be off this read head voltage can be taken. The gate circuit serves to remove the undesired interference effects

. 35 and 33, since they are only shown during the period shown in Fig.4P Period is open. The waveform of the gate voltage of Fig. 4F is generated by the delay element 28 and by the pulse shaper 29, and it is set to cover the period during which a possibly existing read pulse occurs · »· The resulting The suppressed signal is shown in Pig.4G after a full-wave rectification carried out by the rectifier 21. the rectified read voltage is then via a

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The voltage pulse detector 22 is set so that that it only lets through voltage peaks which are above a threshold 36. The output signal of the voltage level detector is shown in Fig.4H. The output of the voltage level detector 22 is now to a gate circuit 23 placed, which is also opened by the signal shown in Fig.4F, so that the required Read signal of the signal of Fig.4G even do, then passes through the gate circuit 23 if undesired signals should break through the gate circuit 27. The output signal the gate circuit 23 corresponds exactly to the data signal actually recorded on the magnetic tape, so that it can be compared with the signal to be recorded so that errors can be detected.

The output signal of the gate circuit 23 becomes a bistable Switch 24 and then fed to a comparison circuit 25 in which it is compared with the information contained in memory 15 is compared. From a pulse applied to the gate circuit 27, a pulse is generated via the delay element 30 and the pulse shaper 31 causes. This pulse is finished again before the next clock pulse of the Clock pulse generator 17 occurs. The pulse is applied to the gate circuit 32 and it appears at the output 26 as an "error" pulse when the input signals of the Comparison circuit 25 do not match at this point in time.

The clock pulse of the clock pulse generator 17 is also used to reset the bistable switch 24.

In this way, the comparison circuit can detect every error that occurs during the actual writing of the data input signal occurred on the tape. If such an error has occurred, the signal can be repeated or an error character can be written in the

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Next bit of the written information is inserted, so that the misspelled information can be disregarded.

In this way, the above-mentioned method offers the possibility of recording a file written in rows on a magnetic tape check digital signal sequence character by character with a signal sequence entered into the machine, like this that the data actually recorded on a tape can be checked continuously and automatically the procedure creates the possibility of itmge to control each step of a step-by-step data recording device, what is expediently used there where the design of a tape transport does not provide direct control over the length of each section of tape Provides.A signal can be derived from the output signal of the reading winding 8, which is a brewable electronic Control of the point at which each section of the tape can be paused so that another section can be recorded Data bits is enabled. The method thus creates an exact control of the length of the strip section, since the signals from the read head can be used to actuate braking devices break up. The distance between the writing gap 5 and the reading gap 6 is used in this way to control the length of the step used,

The embodiment of the invention described above could but can also be changed without further ado, e.g. a Method described wordaa that the encroachment of the Magnetic flux from the write magnetic circuit to the magnetic circuit, containing the reading gap is reduced by the use of a secondary gap in the magnetic circuit of the reading head. There may be other embodiments or other effects

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can be used to prevent this leakage flux from affecting the read signals; For example, some of the write signals can be applied to the read head via a winding so that the leakage flux is reduced in this way,

Claims

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Claims (11)

Claims 1. Method in a data recording process for testing the correct recording of a predetermined signal on a magnetic tape, characterized in that the Signal is recorded on the tape while the tape is stationary or moving at a relatively low ' Moved speed, that the described tape section is moved across a read head and that an output signal of the read head to determine the correct position drawing of the signal is compared with the predetermined signal. · · ".. 2. The method according to claim 1, characterized in that when applied to the technique of step-by-step recording, the passage of the described section of the tape across the reading head from the normal movement of the. 'Band from one stride to another at one Write head is effected, '; 3. Data recording device, characterized by a device for recording a signal on a magnetic tape, means for reading the signal recorded on the tape adjacent thereto; and one Arrangement - for comparing what is contained on the tape. Signal with a signal that should be recorded. 4. Data recording device according to claim 3, characterized in that · * · shows that the writing and reading devices are combined in a single tape head. 5. Recording head, characterized by magnetic gaps for recording and reading signals on a recording tape. 909838/1433 6. Recording head according to claim -5, characterized by two magnetic circuits, which have a magnetically conductive pot section in common. 7. Recording head according to claim 5 or 6, characterized by an arrangement for reducing the leakage flux from a write magnetic circuit to a read magnetic circuit. 8. Recording tape head according to claim 7, characterized in that that the arrangement for reducing the leakage flux a device for increasing the magnetic Contains flow of a reading gap in the recording head. 9. A recording tape head according to claim 8, characterized in that said means for increasing the magnetic resistance consists of a secondary magnetic gap in the reading magnet circuit. 10. A recording tape head according to any one of claims 5 to 9, characterized by arrangements for independently recording two or more tracks on a recording tape. 11. Data recording device according to claim 3, characterized by an arrangement for storing the signal to be recorded on the tape, a comparison arrangement for Comparing a signal read from the tape with that stored signal and one for detecting one Error in the recorded signal, attractive display arrangement. 8/143