JPH0743765Y2 - Recording current compensator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention switches the value of the recording current to the magnetic record carrier,
The present invention relates to a recording current compensator for reducing the peak shift during reproduction.

(Prior Art) As shown in the recording current waveform diagram of FIG.
There is known a technique for reducing the peak shift at the time of reading by superposing the recording compensation current IP on the IW to perform recording on the magnetic record carrier.

The conventional recording current compensation device is configured to fix the value of the recording compensation current IP or manually adjust the value.

(Problems to be solved by the invention) However, since the peak shift amount varies depending on the characteristics of the magnetic record carrier and the measurement of the peak shift amount is relatively difficult, setting of the value of the recording compensation current IP, or ,
Adjustment was not easy.

The present invention has been made to solve such a problem, and an object thereof is to provide a recording current compensating device capable of automatically optimizing the value of the recording compensation current.

(Means for Solving the Problem) In order to solve the above problem, a recording current compensating apparatus according to the present invention records a peak shift amount evaluation data pattern on a magnetic record carrier and reproduces the data pattern to reproduce a specific data time. A recording compensation current adjusting means for measuring an interval and adjusting a value of the recording compensation current based on a difference between the measured time interval and a preset target time interval is provided.

(Operation) The recording current compensating device automatically adjusts the value of the recording compensation current based on the recording / reproducing result of the peak shift amount evaluation data pattern so as to reduce the peak shift amount.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a recording / reception device equipped with a recording current compensator according to the present invention.
It is a principal part block block diagram of a reproducing | regenerating apparatus.

In this embodiment, a magnetic tape is used as a magnetic record carrier, and after GCR (group coded recording) conversion is performed on information to be recorded, NRZ1 (nonreturn-to-zerochange no
1) It shows the case where it is applied to an apparatus for recording by the method.

The recording / reproducing apparatus 1 includes a recording head 3 for recording on the magnetic tape 2 and a reproducing head 4 for reproducing a signal recorded on the magnetic tape 2. The GCR conversion circuit 5 converts the bit pattern of the recording information given to the input terminal 5a. The converted signal 5b is input to the recording current control circuit 7 via the signal selection circuit 6, converted into the NRZ1 signal by the recording current control circuit 7, and the recording head 3 is driven via the recording amplifier 8. is doing.

The GCR conversion circuit 5 of the present embodiment divides the recording information into groups of 4 bits each and converts the 4 bits into a code of 5 bits. It corresponds to 16 types of 4-bit patterns except for those which are continuous and two which are 0 at both ends.

The recording current control circuit 7 receives the code signal selected by the signal selection circuit 6, the recording current IW given from the D / A converter 9 and the recording compensation current IP given from the D / A converter 10, as inputs. The recording current shown in FIG. 2 is generated.
The recording current control circuit 7 has a circuit for inverting the polarity of the recording current IW for each data 1, a timer circuit for measuring a predetermined time after the polarity reversal of the recording current IW, and a recording current IW for the predetermined time. The recording compensation current IP is superimposed on the circuit. Therefore, the NRZ1 type storage current waveform shown in FIG. 2B is generated for the serial data shown in FIG.

In FIG. 1, a reproducing circuit 11 includes a preamplifier 11a for amplifying a signal from the reproducing head 4, a differentiating circuit 11b for differentiating an output signal of the preamplifier 11a, and a reproducing output signal f of a logical level based on the output of the differentiating circuit 11b. Generating a comparator
It is composed of 11c. The logical level reproduction output signal f which is the output of the reproduction circuit 11 is input to the decoder circuit 12,
The decoder circuit 12 is inversely converted and the original record information is output to the reproduction output terminal 13.

The recording current compensator 14 includes a CPU 15 which constitutes recording compensation current adjusting means, two D / A converters 9 and 10, a counter 16 which constitutes means for measuring a time interval of specific data, and a peak shift amount evaluation. The data pattern generating circuit 17 and peripheral circuits thereof. The CPU 15, the D / A converters 9 and 10, and the counter 16 are connected by a bus 18. D / A converter 9
Latches the data relating to the recording current supplied from the CPU 15, and outputs the recording current IW corresponding to this data.
The D / A converter 10 is configured to latch the data relating to the recording compensation current value given from the CPU 15 and output the recording compensation current IP corresponding to this data.

The terminal 19 is an input terminal of a reference clock for time measurement, and the reference clock 19a applied to this terminal 19 is applied to the count input terminal 16a of the counter 16 via the NOR gate 20. The reproduction output signal f which is the output of the reproduction circuit 11 is applied to the other input terminal of the NOR gate 20, and the reference clock 19a is input to the counter 16 only while the GCR signal is at the L level. Thus, the L level time interval of the reproduction output signal f can be measured.

Further, a D / A converter 21 is connected to the bus 18, and the count value of the counter 16 is directly latched via the bus 18 or the count value given via the CPU 15 is latched to count. The analog output voltage corresponding to the value is output to the monitor output terminal 22.

The peak shift amount evaluation data pattern generation circuit 17 repeatedly generates a pattern having a predetermined bit length, and is configured by, for example, a ROM storing predetermined code data, or a combination of a predetermined bit counter and a decoding circuit or the like. can do. In this embodiment, the GCR-converted code is recorded by the NRZ1 method, and when the code is reproduced, a pattern having the maximum peak shift amount at the time of reading is generated.

FIG. 3A is a waveform diagram of the pattern of the peak shift amount evaluation data in this embodiment.

When the start input signal is applied to the start input terminal 23, the CPU 15 outputs the H level signal to the port output 15a,
The peak shift amount evaluation pattern generation circuit 17 is driven to the pattern generation state, and the signal selection circuit 6 selects the evaluation data pattern a.

As a result, the peak shift amount evaluation data pattern a is continuously recorded on the magnetic tape 2. The recorded evaluation data pattern a is reproduced by the reproducing unit 11 to obtain the reproduction output signal f having the logic level shown in FIG. 3 (f). Since the counter 16 is configured to count the reference clock supplied to the input terminal 19 only when the logical level reproduction output signal f is at the L level, the count value of the counter 16 is the third value. 00 shown in Figure (a)
11001100 This is a measurement of 11 consecutive time intervals in the data pattern. The CPU 15 sequentially changes the value of the recording compensation current IP based on this count value, and when the count value of the counter 16 falls within a predetermined range set in advance,
The recording current compensation operation ends.

Next, a specific example of the recording current compensation operation will be described in detail with reference to the flowchart of FIG. In addition,
In FIG. 4, S1 to S12 indicate steps of the flowchart.

In the compensating operation shown in the flowchart of FIG. 4, the evaluation pattern is recorded while gradually increasing the value of the recording compensation current IP from 0, and the time interval measured by the counter 16 is within the preset target time range. Then, the compensation operation is stopped when the time interval becomes longer than the previously measured time interval, and the recording compensation current value IP at this time is stored.

When the start input signal is applied to the terminal 23, the CPU 15 enters the recording current compensation operation mode, and outputs the output port in step S1.
An H level signal is output to 15a, and the peak shift amount evaluation data pattern a is input to the recording current control circuit 7.
Next, in step S2, preset recording current data is output to the D / A converter 9, and in step S3, data for setting the recording compensation current value to 0 is output to the D / A converter 10. Output. As a result, the peak shift evaluation data pattern a is recorded on the magnetic tape 2 without superimposing the recording compensation current IP.

Next, the CPU 15 outputs a counter clear signal to the counter 16 via the bus 18 for a predetermined time to clear the counter 16 (S4). Then, after a lapse of a fixed time, the count value of the counter 16 is read via the bus 18 and stored in a register or the like inside the CPU 15 (S5). After the CPU 15 repeats the time measurement operation consisting of steps S4 and S5 a predetermined number of times (for example, 8 times) (S6), the CPU 15 calculates an average value of the time measurement data of a predetermined number of times and stores it in a register or the like in the CPU 15. Store (S7). Then, it is determined whether or not the actually measured time measurement data is within the target time interval range (S8). If it is out of the target time interval range, data is output to the D / A converter 10 so as to increase the recording compensation current IP by a preset value (S9), and the operations after step S3 are repeated.

If the average value of the actual measurement data is within the target time interval range, it is determined in step S10 whether the average value of the actual measurement data is larger than the previous measurement data. If it is smaller than the previous measurement data, the process proceeds to step S9. If it is larger than the previous measurement data, the data related to the recording correction current value at this time is stored in the register or the like in the CPU 15 (S11), and the output port 15a The signal of is set to L level (S12), and a series of recording current compensation operation is completed.

Note that the flow shown in FIG. 4 utilizes the fact that the recording compensation current IP and the 11 continuous time intervals of the evaluation data pattern have the relationship shown in the graph of FIG.
The IP value is automatically optimized.

In addition, the CPU 15 outputs the data related to the average value of the measured time intervals to the D / A converter 21 so that the monitor output terminal 2
Since the voltage output corresponding to the time interval is generated in 2,
By observing this voltage with, for example, an oscilloscope, the adjustment state of the peak shift can be visually displayed.

Further, in this embodiment, since the peak shift amount maximum data shift pattern is used as the peak shift amount evaluation data pattern, the recording current can be effectively compensated.

Although the present embodiment has described the case where the recording information is GCR converted on the magnetic tape and is recorded by the NRZ1 method, the code conversion method and the recording method are not limited to the present embodiment, and the magnetic The record carrier may be, for example, a magnetic disk or the like other than the magnetic tape.

Further, the recording current compensating operation may be automatically performed when the power of the recording / reproducing apparatus 1 is turned on, instead of being manually performed at the time of periodic inspection or the like.

(Effects of the Invention) As described above, the recording current compensation device according to the present invention is
The recording compensation current value is adjusted while recording / reproducing the peak shift amount evaluation data pattern so that the time interval of the specific data of the reproduced signal is adjusted within the preset target time interval range. The value of the compensation current can be automatically set to the optimum value.

[Brief description of drawings]

FIG. 1 shows a recording / reception device equipped with a recording current compensator according to the present invention.
FIG. 2 is a block diagram of a main part of the reproducing apparatus, FIG. 2 is a waveform diagram of recording current, and FIG. 3 is a time chart showing a peak shift amount evaluation data pattern and a reproduction output signal of the same data pattern.
FIG. 4 is a flowchart showing the recording current compensation operation, and FIG.
FIG. 6 is a graph showing the relationship between the recording compensation current value and the time interval of specific data, and FIG. 6 is a waveform diagram of the recording current on which the recording compensation current is superimposed. 1 ... Recording / reproducing device, 2 ... Magnetic tape as a magnetic record carrier, 3 ... Recording head, 4 ... Reproducing head, 7 ...
Recording current control circuit, 9,10,21 ... D / A converter, 11 ... Playback circuit, 14 ... Recording current compensator, 15 ... CPU that constitutes recording compensation current adjusting means, 16 ... Specific data , Which constitutes the time interval measuring means, 17 ... Peak shift amount evaluation data pattern generation circuit, 19 ... Reference clock input terminal, 23 ... Recording current compensation operation start input terminal.

Claims (1)

[Scope of utility model registration request] 1. A data pattern for evaluating a peak shift amount in an apparatus for performing recording on a magnetic record carrier by superimposing a recording compensation current for a predetermined time from the time when the polarity of the recording current is reversed to a predetermined recording current. To the magnetic record carrier, means for reproducing the peak shift evaluation data pattern recorded on the magnetic record carrier to measure the time interval of specific data, and the time interval of the measured specific data and A recording current compensating device, comprising: a recording compensation current adjusting means for adjusting the value of the recording compensation current based on a difference from a set target time interval.