JPH03185692A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform after-recording by surely performing detection by detecting a subcode area by using a self-running counter circuit synchronized with a synchronizing signal for ATF(automatic track finding) tracking control. CONSTITUTION:A synchronizing signal detection circuit 26 which detects the synchronizing signal for ATF tracking control from reproducing signals SRF outputted from magnetic heads 20A, 20B is provided. A counter circuit 28 which repeats the count operation of a prescribed clock signal CK in the scanning period of the magnetic heads 20A, 20B and repeats the count operation by loading prescribed set data DSET based on the detection result ATSY of the synchronizing signal detection circuit 26, and a mode switching circuit 30 which outputs the switching signal DMD of a recording/reproducing mode based on a count result DCNT are provided. Therefore, the count operation of the counter circuit 28 can be synchronized with the scan of the magnetic heads 20A, 20B. In such a way, the after-recording can be surely performed by detecting the subcode area with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a magnetic recording and reproducing device, and can be applied to, for example, a digital audio tape recorder that records and reproduces digital audio signals.

B. Summary of the Invention The present invention provides a magnetic recording/reproducing device that reliably detects a subcode area by detecting the subcode area using a self-running counter circuit synchronized with a synchronization signal for racking control (ATF). You can do dubbing.

C. Prior Art Conventionally, a magnetic recording and reproducing apparatus (hereinafter referred to as a digital audio recorder) that records and reproduces digital audio signals using a rotating drum is capable of dubbing subcode data.

That is, in a digital audio tape recorder, AT F (automatic track f
(inding) The magnetic tape is played back under tracking control.

At this time, the subcode area is detected based on the synchronization signal for racking control (ATF), and based on the detection result, during the period in which the magnetic head scans the subcode area,
Switches from playback mode to recording mode.

On the other hand, if the synchronization signal for ATF tracking control cannot be detected due to dropout, the subcode area is detected based on the output signal of the position detection sensor attached to the rotating drum.

As a result, in the digital audio tape recorder, only the subcode data in the subcode area can be rerecorded, and the subcode data can be dubbed.

D Problems to be Solved by the Invention Incidentally, in a position detection sensor, since errors are inevitable in mounting, the detection accuracy of the sub-code area is correspondingly lowered.

Therefore, conventionally, in digital audio recorders, the output signal of the position detection sensor is delayed by using a delay circuit that can adjust the delay time, and this allows the installation of the position detection sensor to correct the error. It was designed to detect subcode regions.

Therefore, in order to detect the subcode area with high accuracy based on the output signal of the position detection sensor, as in the case of using the synchronization signal for racking control as the reference, the adjustment precision of the delay time must be adjusted accordingly. If the adjustment accuracy is low, there is a problem that the subcode data cannot be accurately dubbed.

The present invention has been made in consideration of the above points, and aims to propose a magnetic recording/reproducing device that can reliably detect the subcode area and perform dubbing even when the synchronization signal for ATF tracking control cannot be detected. It is something.

Means for Solving Problem E To solve this problem, the present invention provides a synchronization signal detection circuit that detects a synchronization signal for racking control from the reproduction signal SIF output from the magnetic heads 20A and 20B. 26, the counting operation of a predetermined clock signal CK is repeated in the scanning period of the magnetic heads 2OA and 20B, and the predetermined setting data [)sEt is loaded based on the detection result ATSY of the synchronization signal detection circuit 26, and the counting operation is repeated. A counter circuit 28.30 and a mode switching circuit 30 that outputs a recording/reproducing mode switching signal DN (l) based on the count result ocNt of the counter circuit 28.30 are provided.

Predetermined setting data D is applied to the counter circuits 28 and 30 that repeat counting operations in the scanning period of the 1-action magnetic heads 2OA and 20B based on the detection result ATSY of the synchronization signal detection circuit 26.
By loading stT and repeating the counting operation, the counting operation of the counter circuit 28, 30 can be synchronized with the scanning of the magnetic heads 20A, 20B.

Therefore, the count result of the counter circuit 28.30 D CW
Recording/reproducing mode switching signal based on T, 411
If you output the , you can reliably perform dubbing.

G example Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 indicates a digital audio tape recorder as a whole, and performs dubbing of recorded data DIIEI:.

That is, in the digital audio tape recorder 1, the rotating drum 2 uses guide rollers 4 to 7 and an inclined guide 8.9 to wrap the magnetic tape 10 at an angle of 90 degrees.
is wound diagonally and rotated at a predetermined speed.

At this time, the capstan 12 is connected to the capstan motor 14.
The magnetic tape 10 is driven at a predetermined speed together with the pinch roller 16, and as a result, the magnetic tape 12 is
Magnetic heads 20A and 20B mounted on the rotating drum 10
The scanning trajectory is sequentially formed diagonally.

Furthermore, as shown in FIG.
C is applied to the switching pulse signal generation circuit 22, and a switching pulse signal SWP (
FIG. 2(A)) is generated.

The reproduction amplification circuit 24 switches its operation based on the control signal D0, and thereby reproduces the reproduction signal 5IF ( Second
The magnetic head 2
During the period when OA and 20B scan the subcode area,
Stop operation.

The synchronization signal detection circuit 26 detects a synchronization signal for ATF racking control from the output signal of the regenerative amplifier circuit 24, and the ATF detection signal ATSY (see FIG. )).

The counter circuit 28 sequentially counts a predetermined clock signal CK to count 4ItI)cNt (Fig. 2(D)
)) to the decoder circuit 30, the count value DcN? When it reaches a predetermined value, it is reset by the reset signal CTR3T (FIG. 2 (E)) output from the decoder circuit 30, and the counting operation is repeated again, whereby 1/2 of the switching pulse signal SWP
The counting operation is repeated in sequence at a period (that is, the scanning period of the magnetic heads 2OA and 20B).

Furthermore, when the signal level of the ATF detection signal ATSY rises, the counter circuit 28 outputs predetermined setting data D1!
(indicated by a broken line in FIG. 2), and the clock signal CK is counted from the setting data DSET.

In other words, the area where the synchronization signal is recorded is the A head 2OA.
At time t1 when scans, setting data D of value L1
In contrast to loading svT, at time t2 when the A head 20A scans the area where the remaining synchronization signals are recorded, setting data D and T of value L2 are loaded.

Similarly, at time t3 when the B head 20B scans the area where the synchronization signal is recorded, the setting data D of the value L3,
At time t4, when the B head 20B scans the area where the remaining synchronization signals are recorded,
(Loads the IL4 setting data DSET.

As a result, in the counter circuit 28, the digital audio tape recorder 1 switches from the playback mode to the dubbing mode, and even if the synchronization signal for ATFI-racking control cannot be detected due to dropout at time t41, the previous Repeat the counting operation based on the setting data D SET at time t3,
The counting operation can be repeated in synchronization with the scanning of the magnetic heads 20A and 20B.

The decoder circuit 30 outputs a reset signal CTR3T, and also outputs a control signal DMfi whose signal level rises when the count value DCNA falls within a predetermined setting range.
As a result, the signal level of the control signal D0 is raised during the period in which the magnetic heads 2OA and 20B scan the subcode area.

The recording signal generation circuit 34 generates recording data D□ for dubbing.
, is converted into a recording signal S□, (Fig. 2 (G)), and the recording signal S1c is sent to the magnetic head 2 through a recording amplifier circuit.
Output to OA and 20B.

At this time, the recording signal generation circuit 34 identifies the AB heads 20A and 20B based on the switching pulse signal SWP and generates the recording signal 5llfe, and during the period in which the signal level of the control signal I)to rises, the recording Signal S□. Output.

In this way, even if it is not possible to detect the synchronizing signal for ATF racking control due to dropout, the recording signal for post-recording is detected based on the count value of the counter circuit 28, which repeats the counting operation in synchronization with the scanning of the magnetic heads 20A and 20B. By outputting 5ctc, it is possible to detect the subcode area with much higher accuracy than when using a position detection sensor and output the recording signal SREt, which allows for reliable dubbing. can.

In this way, the counter circuit 28 and the decoder circuit 30 repeat the counting operation of the predetermined clock signal CK in the scanning period of the magnetic heads 2OA and 20B, and load the predetermined setting data D stT based on the detection result CATSY of the synchronization signal detection circuit 26. In contrast, the decoder circuit 30 constitutes a self-running counter circuit that repeats counting operations.
Based on the count result D_CNT of the counter circuit 28, the recording/reproduction mode switching signal D1. A mode switching circuit that outputs an ID is configured.

In the above configuration, the counter circuit 28 sequentially counts the clock signal CK, and is reset by the reset signal CTR5T output from the decoder circuit 30 when the count value DCNT reaches a predetermined value. The counting operation is repeated at the scanning period of .

At this time, the counter circuit 28 controls the magnetic heads 20A and 2.
At the timing when 0B scans the synchronization signal recording area for ATFI-racking control, predetermined setting data D3! T
This causes the counting operation to start from the magnetic head 2O.
It is designed to be synchronized with the scanning timing of A and 20B.

As a result, the count value DCN of the counter circuit 28?
By determining this with the decoder circuit 30, it is possible to obtain a control signal [)we whose signal level rises during the period when the magnetic healds 20A and 20B scan the subcode area.

According to the above configuration, the counter circuit 28 repeats the counting operation at the scanning period of the magnetic heads 20A and 20B.
At the timing when the magnetic heads 2OA and 20B scan the synchronization signal recording area for ATF tracking control, predetermined setting data D8. ? By loading the counter circuit 28, the counting operation of the counter circuit 28 is controlled by the magnetic heads 2OA and 20.
It can be synchronized with the timing of the B scan.

Therefore, by switching the recording/reproducing operation based on the count value of the counter circuit 28, the subcode area can be detected with high accuracy and post-recording can be performed reliably.

In the above-mentioned embodiment, the case where the magnetic tape is wound at an angle of 90 degrees has been described, but the present invention is not limited to this, and can be widely applied to magnetic recording/reproducing devices having various configurations.

Further, in the above-described embodiments, a case was described in which digital audio signals were recorded and reproduced, but the present invention is not limited to this, but can be widely applied to magnetic recording and reproduction apparatuses that record and reproduce various data instead of digital audio signals. be able to.

AT is added to the counter circuit that repeats counting operation in the scanning period
F) By loading predetermined setting data 0SET at the timing when the synchronization signal for racking control is output and switching the recording/reproducing operation based on the count value of the counter circuit, the subcode area is detected with high precision. It is possible to obtain a magnetic recording and reproducing device that can reliably perform dubbing.

[Brief explanation of drawings]

FIG. 1 is a route diagram showing a digital audio tape recorder according to an embodiment of the present invention, and FIG. 2 is a signal waveform diagram for explaining its operation. 1...Digital audio chip recorder,
2...Rotating drum, 10...Magnetic tape, 2OA, 20B...Magnetic head, 22...
...Switching pulse signal generation circuit, 26...
... Synchronous signal detection circuit, 28 ... Counter circuit, 30 ... Decoder circuit, 34 ...
Recording signal generation circuit.

Claims (1)

[Scope of Claims] A synchronization signal detection circuit that detects a synchronization signal for ATF tracking control from a reproduction signal output from a magnetic head; a counter circuit that repeats the counting operation by loading predetermined setting data based on the detection result of the synchronization signal detection circuit; and a mode switching circuit that outputs a recording/playback mode switching signal based on the counting result of the counter circuit. A magnetic recording/reproducing device comprising: