JPH0366017A - Digital magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the command of head cleaning or the automatic processing of the head cleaning from being executed in the case that there is little dirt on the head and also there is few errors in reproduced digital data by adding an error detection circuit and an error counting circuit. CONSTITUTION:The summed-up time of a summed-up timer 4 is monitored by a time measurement circuit 5. When the time fixed in advance is measured in the summed-up, the timer 4 is reset and started and also an output pulse is supplied to the error detection circuit 6 by the time measurement circuit 5. The error detection circuit 6 is started by the output pulse, and the error in the digital data which is read out by a magnetic head 1 and demodulated by a recording and reproducing circuit 2 is detected by the detection circuit 6. The number of errors detected by the detection circuit 6 is counted by an error counting circuit 7, and when the number of the errors exceeds a threshold fixed in advance, a head cleaning signal is outputted by the error counting circuit 7. And then, the display of the head cleaning or the automatic head cleaning is executed by the head cleaning signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] A digital magnetic recording/reproducing device including means for detecting dirt on a recording/reproducing head in a digital magnetic recording/reproducing device such as a digital audio recorder (DAT) [Prior Art] Digital magnetic recording device If the recording/reproducing head of a recording/reproducing device becomes dirty, errors will occur in the recorded or reproduced digital data.

In order to solve such problems, conventionally, as shown in FIG. 4, the operation time of the magnetic head is determined based on the signal output from the recording/reproducing circuit 2 during the period when recording/reproducing is performed by the magnetic head l. A recording/playback time cumulative timer 4 is provided to cumulatively total the recording/reproducing time, and when the cumulative time coincides with the time preset in the time measuring circuit 5, the user is notified by a head cleaning display means or the like that head cleaning should be performed. was being carried out.

Note that the recording/reproducing circuit 2 is read by the magnetic head l.
Needless to say, the data reproduced into a digital signal is subjected to error correction by the error correction circuit 3, etc., and then sent to a utilization device such as a sound reproduction device.

However, the degree of contamination of the recording/reproducing head varies depending on the contamination of the used tape itself and the nature of its surface, and even if the above-mentioned predetermined time has elapsed, if there is little contamination, it is not necessarily necessary to perform head cleaning.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a digital magnetic recording/reproducing device that generates a display instructing head cleaning or a head cleaning signal for automatically controlling head cleaning depending on the dirt on the head. .

[Means for solving problems]

Referring to the embodiment of the present invention shown in FIG. recording/reproduction time determining means 4 for operating the error detector 6 and resetting and starting the timer when the timer 4 has counted a predetermined time;
．． 5 and an error counting means 7 for outputting a head cleaning signal when the output of the error detector 6 exceeds a predetermined value.

[For production]

Even when the predetermined head cleaning time has arrived, if the head is less contaminated and the reproduced digital data has fewer errors, it is possible to prevent head cleaning from being instructed or from being automatically processed.

〔Example〕

As mentioned above, FIG. 1 shows an embodiment of the present invention, and will be described with reference to the operational diagram of FIG. 2.

In normal playback conditions, digital data read from the recording medium by the magnetic recording/playback head 1 is sent from the recording/playback circuit 2 to the error correction circuit 3, where errors in the read digital data are corrected. Sent to a playback device, etc. It goes without saying that the digital data to be recorded on the recording medium is also supplied to the recording/reproducing circuit 2 and is recorded/reproduced in response to the dot 1.

This recording/playback circuit 1 during recording/playback.
The recording/playback time cumulative timer 4 measures time based on the output from That is, at the left end of the figure, the cumulative time to has already been set in the cumulative timer, and when recording/reproduction is started, the value of the cumulative timer increases successively as shown.

The time measurement circuit 5 monitors the cumulative time of the cumulative timer 4 and determines when a predetermined time is reached. When the BIT is cumulatively counted, the cumulative timer 4 is reset and started, and the timer shown in FIG.
) is supplied to the error detection circuit 6. If recording and playback were to be performed continuously, (a) this output pulse would be output from the time measurement circuit 5 at every time corresponding to the predetermined time T, as illustrated in the second section of the figure. Output.

The error detection circuit 6 is activated by this output pulse, and detects errors in the digital data read by the magnetic head 1 and demodulated by the recording/reproducing circuit 2.

The error counting circuit 7 counts the number k of errors detected by the digital error detection circuit 6 as shown in FIG. Output the head cleaning signal shown in d).

This head cleaning signal causes a head cleaning display indicating that head cleaning should be performed if the magnetic recording/reproducing device is equipped with a head cleaning display means, and also causes the magnetic recording/reproducing device to automatically perform head cleaning. If an automatic head cleaning means is provided, the head cleaning signal can be used to automatically perform the head cleaning.

FIG. 3 is a flowchart illustrating an embodiment of the process according to the present invention, and this routine is executed during all operating modes of the recording/reproducing apparatus.

In step (2), the recording/playback time t counted by the cumulative timer 4 is compared with a predetermined time T by the time measuring circuit 5.
This step is repeated until <t, but when Ti is reached, the process moves to the next step (2) and checks whether or not this recording/playback device is in the playback state. If not, repeat this step and wait for playback status.

When the device enters the playback state, the cumulative timer 4 is set in the next step ■.
and at the same time activate the error detection circuit 6 and cause the error counting circuit 7 to perform error counting,
In the following step (2), the number of errors counted k is compared with a threshold value.

If the number of errors k is larger than this threshold value, a head cleaning signal is output in the next step (2), and the head cleaning is displayed or head cleaning is automatically executed as described above.

〔Effect of the invention〕

According to the present invention, even if the cumulative recording/playback time reaches a predetermined head cleaning time, head cleaning is performed if there are few reading errors in the reproduced digital data, that is, if there is little dirt on the recording/playback head. Since no instruction display or automatic head cleaning is performed, a special effect is achieved in that unnecessary processing and time are no longer required.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a time chart for explaining its operation, Fig. 3 is a flow chart showing an embodiment of processing, and Fig. 4 is a block diagram showing a conventional example. It is. Example Figure 1

Claims (1)

[Scope of Claims] A cumulative timer for cumulatively counting the recording/playback time; an error detector for generating an output according to the number of errors in the reproduced digital signal; Recording/playback time determining means for operating an error detector and resetting/starting the timer; and error counting means for outputting a head cleaning signal when the output of the error detector exceeds a predetermined value. A digital magnetic recording/reproducing device comprising: