JPH03116507A - Digital tape recorder device - Google Patents

Abstract

PURPOSE:To make the device easily comply with the variance of the electric characteristic of a magnetic tape and the variance among respective makers by mimically performing recording on the magnetic tape while changing a current value stepwise and then reproducing the recording so that the error rate of every current value may be calculated and setting the current value whose error rate is minimum as a recording current. CONSTITUTION:The device is provided with means 4, 10 and 11 for mimically recording the signal on the magnetic tape 1 while changing the current value stepwise, means 5 and 10 for calculating the error rate of the recording signal of every current value by reproducing the signal mimically recorded, and the means 10 for deciding the current value having the minimum error rate from the calculated result. Furthermore, the means 4 and 10 for setting the decided current value as the optimum recording current are provided. Since the recording current with which the error rate is minimum is set every magnetic tape, the device is made to easily comply with the variance in production of the electric characteristic of the magnetic tape and the variance among the respective makers.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to digital audio equipment (hereinafter referred to as DAT), and particularly relates to a digital tape recorder device using magnetic tape as a recording medium. .

(Prior Art) FIG. 3 shows the relationship between recording current and error rate in a DAT. As shown in this figure, in DAT, there is a point where the error rate of the recording signal is minimum at a certain current value, so it is necessary to find that value as ORC (optimum recording current) and set it in the device. .

As shown in FIG. 4, this ORC is determined by recording signals on a magnetic tape at various current values, reproducing the signals, and examining the current value at which the maximum frequency value was obtained.

However, in commercialized devices, a method is generally adopted in which a master tape is played back, a recording current that minimizes the error rate is detected, and this is fixed in the device.

However, even if the recording current obtained in this way is set to DAT, the error rate will not necessarily be minimized in actual processing. Reasons for this include inappropriate characteristics of the playback equalizer amplifier, differences in the playback output level and recording frequency characteristics between the recorded tape and playback master tape, and variations in the electrical characteristics of the DAT tape, among others. R, which is the electrical property of DAT tape
The influence of manufacturing variations in F-optimal recording current, RF specific output, RF frequency characteristics, override characteristics, C/N, etc., and variations among manufacturers is significant.

Note that the above-mentioned error rate is calculated as follows.

That is, in the DAT's standard mode, analog signals are sampled at 48 KHz and converted to 16-bit digital data. This 16-bit digital data is divided into 8-bit units of data (referred to as symbols) to facilitate signal processing. after that,
This data is recorded on magnetic tape after undergoing complex signal processing. However, in this case, there is a risk that signal dropouts may occur during reproduction due to deterioration of the magnetic tape, clogging of the head, or the like. Therefore, DAT employs an error correction method such as the Reed-Solomon method in order to correct the location where such dropout occurs and reproduce the signal correctly.

In this method, after encoding data, parity pits are generated based on a predetermined equation, and the parity bits are added to the data and recorded on the magnetic tape. At the time of playback, the playback data is inspected. Error data is corrected by detecting dropout and solving a predetermined equation with dropout as X. Furthermore, D.A.
In the case of T, two parity sequences, C1 and C2, are added, and if there is an error in a symbol during signal processing, a C1 or C2 flag is generated.

Count the number of occurrences N at any time T and
The above-mentioned error rate is obtained by calculating +T.

(Problems to be Solved by the Invention) As described above, in the conventional DAT, it has been difficult to reliably obtain a state with a minimum error rate due to variations in the electrical characteristics of the magnetic tape.

The present invention is intended to solve such problems, and it is possible to easily cope with manufacturing variations in electrical characteristics of magnetic tapes and variations between manufacturers by setting a recording current that minimizes the error rate for each magnetic tape. The purpose of this invention is to provide a digital tape recorder device that can perform the following functions.

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned object, the digital tape recorder device of the present invention simulates signal recording while changing the current value in stages on a magnetic tape. means for calculating the error rate of the recorded signal for each current value by reproducing the signal simulated recorded on the magnetic tape by this means, and determining the current with the minimum error rate from the calculation result. The apparatus is equipped with means for determining the current value, and means for setting the current value determined by this means as the optimum recording current for the magnetic tape.

(Function) In the digital tape recorder device of the present invention, after simulating signal recording on a magnetic tape while changing the current value in stages, this is reproduced to record each current value. Calculate the error rate of the signal. Thereafter, the current value with the minimum error rate is determined from the calculation result, and this is set as the optimum recording current for the magnetic tape.

Therefore, according to the present invention, it is possible to set the recording current that minimizes the error rate for each magnetic tape, and it is possible to easily cope with manufacturing variations in electrical characteristics of magnetic tapes and variations among manufacturers (Example ) Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 2 is a block diagram showing the configuration of a digital tape recorder device according to an embodiment of the present invention.

In the figure, 1 is a magnetic tape, and 2 is a rotary head for recording/reproducing digital signals on/from the magnetic tape 1. As shown in FIG. Further, 3 is a recording/reproducing equalizer amplifier that performs frequency compensation during signal recording/reproducing, 4 is a recording current adjustment unit for adjusting the recording current in the rotary head 2, and 5 is a signal recording/reproducing unit that performs signal error correction, etc. 6 is a modulation/demodulation unit that modulates and demodulates the signal. Furthermore, 7 is a memory in which signals to be processed by the signal processing unit 5 are temporarily stored, 8 is a display unit for performing various displays, 9 is an operation unit for performing various input operations, and 10 is the above. This is a system microcomputer that centrally controls each component of the system.

Incidentally, an error rate counting routine is programmed into the system microcomputer 10 described above. Also, the operation section 9
is provided with a current adjustment switch 11 for operating the functions of the recording current adjustment section 4.

Next, the operation for setting the recording current in this DAT will be explained with reference to the flowchart of FIG.

When a command to start recording (REC) is issued, it is first checked whether the current adjustment switch 11 is on or off (step A).

Here, if the current adjustment switch 11 is off, the current fixed mode is set (step B) and the recording process is started (
Step C). Also, if it is on, the recording current is set to the lower limit (for example, 1
0 mA) (Step D). After setting the recording current, the recording process is started from the beginning of the magnetic tape 1, and the counter N is set to "1" (step E).

After this, a preset time (e.g. 2 seconds) is set in the timer.
Every time (seconds) elapses (step F), the value of the counter N is incremented by one (step G), and the recording current is increased by a constant value (for example, 2n+A) (step H).

Such operations are repeated, and when the value of the counter N reaches a preset value (for example, "6") (step I), the recording process is stopped and the magnetic tape 1 is rewound (step J).

Next, the playback process is started from the tape position where recording was started, and the counter is set to "1".

(Step K).

After this, a preset time (e.g. 2 seconds) is set in the timer.
Every time (seconds) elapse (step L), the system microcomputer 10 calculates the error rate of the recording signal, and stores the result in the memory 7 (step M). Along with this operation, the value of the counter (2) is incremented one by one (step N). That is, each error rate is calculated for recording signals recorded with different current values.

Such operations are repeated, and when the value of the counter 1 reaches a preset value (for example, "6") (step O), the reproduction process is stopped and the magnetic tape 1 is rewound (step P).

After this, the system microcomputer 10 checks the minimum error rate among the error rate calculation results corresponding to each current value stored in the memory 7 (step Q), and determines the current value corresponding to this. Then, the value is set in the recording current adjustment section 4 (step R).

After setting the recording current value, normal recording processing is started (step C).

Thus, according to the DAT of this embodiment, it is possible to determine the recording current that provides the minimum error rate for each magnetic tape 1, and to set this in the signal recording system.

Therefore, manufacturing variations in the electrical properties of the magnetic tape 1 and variations among manufacturers can be easily accommodated.

[Effects of the Invention] As explained above, according to the digital tape recorder device of the present invention, it is possible to set the recording current that minimizes the error rate for each magnetic tape, so that the electrical characteristics of the magnetic tape can be adjusted. It is possible to easily deal with manufacturing variations and variations between manufacturers.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the flow of setting the recording current in a DAT according to an embodiment of the present invention, Fig. 2 is a block diagram showing the configuration of the DAT in Fig. 1, and Fig. 3 shows recording current and errors. FIG. 4 is a diagram showing the relationship with the rate, and FIG. 4 is a diagram showing the reproduction frequency characteristics depending on the magnitude of the recording current. DESCRIPTION OF SYMBOLS 1... Magnetic tape, 2... Rotating head, 3... Recording/reproduction equalizer amplifier, 4... Recording current adjustment section,
5... Signal processing section, 6... Modulation/demodulation section, 7... Memory, 8... Display section, 9... Operation section, 10... System microcomputer, 11... Current adjustment switch.

Claims (1)

[Claims] Means for simulating recording of signals on a magnetic tape while changing current values stepwise; means for calculating the error rate of the recording signal for each current value; means for determining the current value with the minimum error rate from the calculation result; and setting the current value determined by the means as the optimum recording current for the magnetic tape. A digital tape recorder device characterized by comprising means for.