JPH0743766Y2 - DAT device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a DAT device, and more particularly to a DAT device that obtains optimum characteristics during double-speed recording / reproducing and normal recording / reproducing.

(Prior Art) A DA that records a digital signal on a magnetic tape while reading and reproducing the digital signal recorded on the magnetic tape.
The T-device can obtain extremely high-quality reproduced sound without signal deterioration during recording and reproduction.

As shown in FIG. 2, the basic structure of a conventional DAT device is that a signal recorded on a magnetic tape 1 is transferred to a set of magnetic heads 2a arranged on a drum and having different polarities of azimuth angles. It is configured to read at 2b.

The digital signals read by the magnetic heads 2a and 2b are subjected to desired frequency correction processing in the normal speed recording / reproducing equalizer 4a for normal speed, and are supplied to the signal processing / system control circuit 6.

An ATF error signal is extracted from the reproduction signal from the recording / reproduction equalizer 4a by the ATF circuit 5a and supplied to the signal processing / system control circuit 6.

The signal processing / system control circuit 6 performs well-known DAT signal processing and system control of the mechanism based on the signals from the recording / reproducing equalizer 4a and the ATF circuit 5a.

The operation at the time of reproduction is performed by a processing process reverse to the above operation.

(Problems to be Solved by the Invention) As described above, the conventional DAT device performs recording / reproduction at a constant speed (normal speed) and does not have the double-speed recording and double-speed reproduction functions. ) There is a problem that recording, double speed (high speed) reproduction, search, etc. are impossible. Further, even if possible, since the circuit is not configured to support the double speed, the following problem occurs.

That is, since the conventional DAT device does not have the double-speed recording and double-speed reproducing functions, an equalizer for normal recording / reproducing must be provided for each head having different polarities of the azimuth angle.

Also, because it does not have a double speed playback function, there is also one type of low pass filter (LPF) or band pass filter (BPF) for the pilot signal 130KHz for ATF and an equalizer for detecting the pilot sync signal. Not only that.

However, at the time of double speed recording, the recording frequency and the relative speed of the head and the magnetic tape are doubled and the recording wavelength is the same, but since the recording frequency is increased, the high frequency loss such as eddy current loss of the magnetic tape becomes large. However, there is a drawback that the magnetic force applied to the magnetic tape is reduced.

Also, at the time of double speed reproduction, the relative speed of the magnetic head and the magnetic tape doubles, and the reproduction output in the low range increases, but as the frequency increases, the recording wavelength and the magnetic head gap get closer, and the reproduction output in the high range increases. It decreases, and the error rate is bad with the equalizer curve of normal playback as in the past,
There is a drawback that good reproduction cannot be performed.

Therefore, an object of the present invention is to provide a DAT device capable of obtaining optimum characteristics for double-speed recording / reproducing and normal recording / reproducing.

(Means for Solving the Problems) In order to solve the above problems, a DAT device according to the present invention is a DAT that performs recording and reproduction at a normal speed and a double speed via a pair of magnetic heads having different polarities of azimuth angles. In the apparatus, two equalizer means having optimum equalizer characteristics for each of the normal speed and the double speed, and a switching means for switching and selecting the optimum equalizer means corresponding to the two equalizer means at the time of operation of each of the normal speed and the double speed. And is configured.

(Function) In the DAT device according to the present invention, the optimum recording / reproducing equalizer characteristics are set for the normal speed and the double speed, respectively, and the optimum above-mentioned is selected according to the normal speed or the double speed recording / reproducing operation state of the DAT device. Since the equalizer characteristic is switched and selected, the optimum operating characteristic is always obtained even at the normal speed and the double speed operation.

(Example) Next, this invention is demonstrated, referring drawings.

FIG. 1 is a block diagram showing the basic configuration of a DAT device according to the present invention.

1. In FIG. 1, the components designated by the same reference numerals as in FIG. 2 are the same components as in FIG.

In this embodiment, two equalizers 4a and 4b for normal speed and double speed are provided as recording / reproducing equalizers.
ATF circuits 5a and 5b for normal speed and double speed are provided, and these are selectively used by using changeover switches 3a, 3b and 3c.

The magnetic heads 2a and 2b have polarities of azimuth angles different from each other, the azimuth angle is 20 °, and the head gap is set so as to be compatible with double speed reproduction.

The changeover switches 3a to 3d are switched and controlled by the signal processing / system control circuit 6, and at the normal speed recording / reproducing, the normal speed recording / reproducing equalizer is in the switching state shown in FIG.
4a and the normal speed ATF circuit 5a are selectively operated. On the other hand, at the time of double speed recording / reproducing, the double speed recording / reproducing equalizer 4b and the double speed ATF circuit 5b are switched to be selectively used.

That is, the normal speed recording / reproducing equalizer 4a has a predetermined reproduction output when the reference tape is reproduced, the equalizer characteristics are set so that the error rate becomes the best, and the reproduction output of each frequency when reproducing the recorded magnetic tape. Is set to a predetermined level.

The double speed recording / reproducing equalizer 4b is a recording and reproducing equalizer at double speed, and the recording equalizer is set so that the reproduction output at each frequency becomes a predetermined level when the double speed recorded tape is reproduced at normal speed. Further, the reproduction equalizer is set so as to reproduce the pilot level so that the ATF is possible, and also to maximize the error rate due to the reproduction output.

The normal speed ATF circuit 5a is an ATF circuit at the time of normal reproduction, which is an LPF for extracting a pilot signal of 130 KHz and an A for pilot detection.
The TF sync signal is taken out and an error signal for ATF is generated by the leak amount of the pilot signal from the adjacent track to the reproduction track.

Also, the double speed ATF circuit 5b is a 260KHz ATF circuit at the time of double speed reproduction.
LPF or BPF that extracts the pilot signal that has become and the pilot detection AT that has doubled the frequency during normal playback
The F sync signal is taken out and an error signal for ATF is generated by the leak amount of the pilot signal from the adjacent track to the reproduction track.

The signal processing / system control circuit 6 is a well-known DAT.
We perform system control of signal processing and mechanism of
The internal operation clock is switched between normal speed reproduction and double speed reproduction, signal processing and mechanism control are performed, and the switching signal of the selector switch 3a is output as described above.

Information recorded on the magnetic tape 1 is recorded on the magnetic heads 2a and 2b.
Normal speed recording / playback equalizer picked up by
It is input to the signal processing / system control circuit 6 via 4a.

The output of the normal speed recording / reproducing equalizer 4a is input to the normal speed ATF circuit 5a, and a tracking error is generated and sent to the signal processing / system control circuit 6.
Also, during normal recording, the signal processing / system control circuit 6 sets the changeover switches 3a and 3b to the positions shown in the figure and records.

On the other hand, in the double speed recording, the signal processing and system control circuit 6, the mechanism control and the signal processing are set so that the internal clock operates at the double clock.
Recording is performed by switching the changeover switches 3a and 3b to the double speed recording / reproducing equalizer 4b side.

During double speed reproduction, the signal processing / system control circuit 6 similarly sets the mechanism signal processing so that the internal clock operates at the double clock, and further, the changeover switch.
3a-3d equalizer for double speed 4b side and double speed ATF circuit 5
Switch to the b side. Therefore, the signal recorded on the magnetic tape 1 is picked up by the magnetic heads 2a and 2b and input to the double speed recording / reproducing equalizer 4b. The output of the equalizer 4b is output to the double speed ATF circuit 5b to generate a double speed ATF error signal.
The signal processing / system control circuit 6 is a double speed ATF.
Double speed reproduction is performed by the output of the circuit 5b and the output of the double speed ATF circuit 4b.

(Effect of the Invention) As described above, the DAT device according to the present invention is configured to set the optimum recording / reproducing equalizer characteristics during the normal speed operation and the double speed operation. Normal speed recording / playback and double speed recording / playback can be realized using the same mechanism and the same head.

[Brief description of drawings]

FIG. 1 is a basic configuration block diagram showing an embodiment of a DAT device according to the present invention, and FIG. 2 is a basic configuration block diagram of a conventional DAT device. 1 ... Magnetic tape, 2a, 2b ... Magnetic head, 3a-3d ...
Changeover switch, 4a …… Normal speed recording / playback equalizer, 4b
…… Double speed recording / playback equalizer, 5a …… Normal speed ATF circuit, 5b …… Double speed ATF circuit, 6 …… Signal processing / system control circuit.

Claims (1)

[Scope of utility model registration request] 1. Recording and reproduction are performed at a normal speed and a double speed via a pair of magnetic heads having mutually different polarities of azimuth angles.
In the DAT device, two equalizer means having optimum equalizer characteristics for each of the normal speed and the double speed, and a switch for selecting the optimum equalizer means corresponding to the two equalizer means at the time of operation of each of the normal speed and the double speed A DAT device comprising means and.