JPH0422284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording and reproducing apparatus that records and reproduces information on a magnetic tape using a so-called helical scanning method.

BACKGROUND ART In a helical scanning type recording/reproducing device, a pair of magnetic heads are arranged around a rotating cylinder at an interval of 180 degrees, and a magnetic tape is guided and run over more than half of the circumference of the rotating cylinder. The magnetic head is rotated in the same direction as the longitudinal direction of the magnetic tape, and one field of video signals is recorded on one track formed obliquely to the longitudinal direction of the magnetic tape. In one rotation of a pair of magnetic heads, two fields' worth of video signals are alternately recorded on the magnetic tape as one frame's worth of video signals. During playback, a pair of magnetic heads alternately scans the track on which the video signal has been recorded, and the video signal is sequentially read. Since the magnetic tape is wound around more than half the circumference of the cylinder and recorded, the video signals overlap at both ends of the track on the magnetic tape, so the video signals read alternately by a pair of magnetic heads are The overlapping portion is removed and a continuous video signal is created.

Problems to be Solved by the Invention In the conventional helical scanning type magnetic tape recording/reproducing apparatus as described above, either recording or reproduction of a video signal is selected and operated. Therefore, in the prior art, while information such as a video signal is being recorded or reproduced, it is not possible to simultaneously perform the reproduction or recording.

Another conventional example is Utility Model Application No. 59-27677. This conventional example discloses a technique using four video heads whose recording/reading operation states can be switched. However, in reality, there is a function that allows four video heads to be used continuously for recording, a function that allows these four video heads to be used continuously for playback, and a function that allows two video heads to record signals. while doing the other 2
There is only a technique disclosed that allows a single video head to perform one of the functions of so-called monitor reproduction of the signal immediately after recording. Therefore, this conventional example has the problem that two channels cannot be used at the same time, and only one channel of signals can be used, resulting in low usability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic tape recording and reproducing apparatus that can simultaneously record and reproduce information on a magnetic tape and has significantly improved operability.

Means for Solving the Problems The present invention provides a helical scanning type recording and reproducing apparatus in which a rotating magnetic head scans a track diagonally with respect to the longitudinal direction of the magnetic tape. A pair of first magnetic heads are disposed in mutually symmetrical positions on the cylinder head, and each second magnetic head of the pair is in sliding contact with the cylinder head.
A recording signal that is arranged between each first magnetic head at equal intervals from each first magnetic head, and that creates a signal that is recorded on the magnetic tape via the first magnetic head or the second magnetic head. creating means; signal reading processing means for reading and processing signals from the magnetic tape via the first magnetic head or the second magnetic head; the first magnetic head and the second magnetic head;
A head switching means for connecting a recording signal generating means and a signal reading processing means, wherein a first magnetic head and a second magnetic head are connected to the recording signal generating means for each track, and the first magnetic head and the second magnetic head are connected to the recording signal generating means. to the signal reading processing means for each track, and connecting the first magnetic head and the second magnetic head to either the recording signal generating means or the signal reading processing means for each track. A rotary tape recording and reproducing apparatus is characterized in that it includes a head switching means as described above.

Function In the magnetic tape recording and reproducing apparatus according to the present invention,
A pair of first magnetic heads and a second magnetic head are arranged on the cylinder head, each pair being arranged on two mutually perpendicular diameter lines. located between every other first group of tracks on the magnetic tape scanned by the first magnetic head and said first group of tracks on the magnetic tape scanned by the second magnetic head. Every other track of the second group is used as two completely independent channels.

That is, two types of separate recording signals can be independently recorded on each group of the magnetic tape by the first magnetic head or the second magnetic head. Further, the signals recorded on the two groups of tracks on the magnetic tape can be independently read by the first magnetic head or the second magnetic head. Further, the first magnetic head can record recording signals on the first group of tracks on the magnetic tape, and the second magnetic head can read the signals recorded on the second group of tracks on the magnetic tape. Alternatively, the magnetic heads that perform the simultaneous recording and reading operations may be reversed. This greatly improves operability.

Embodiment FIG. 1 is a block diagram showing the configuration of a magnetic tape recording and reproducing apparatus according to an embodiment of the present invention. The amplified video signal derived from the tuner or line input is applied to the input terminal T1. The video signal applied to input terminal T1 is divided into two parts, one of which is input to low pass filter (LPF) 1,
Color subcarrier components and audio carrier components are removed. As a result, the luminance signal output from the low-pass filter 1 is input to a signal processing circuit 2 comprising a pre-emphasis circuit, a clamp circuit, and the like. The luminance signal processed by the signal processing circuit 2 is input to the FM modulation circuit 3 and becomes an FM modulated signal.
The FM modulated luminance signal is given to the mixing circuit 4. The other of the video signals applied to the input terminal T1 is applied to a band pass filter (BPF) 5. A carrier color signal is extracted by a bandpass filter 5, and the carrier color signal is inputted to a frequency conversion circuit 6 and converted into a low-band carrier color signal. The low-pass color signal is input to a low pass filter (LPF) 7 and then input to the mixing circuit 4. The mixing circuit 4 mixes the FM-converted luminance signal and the low frequency carrier color signal, and the mixed signal is amplified by the recording amplifier 8 and applied to the magnetic head switching means SW.

The signal output from the recording amplifier 8 is sent to the changeover switch SW1 of the magnetic head changeover means SW.
common terminal S11 and changeover switch SW2
are respectively applied to the common terminal S21. Individual terminal S12 of switch SW1 is a changeover switch.
It is connected to the individual terminal S31 of SW3, and the individual terminal S22 of changeover switch SW2 is connected to the individual terminal S41 of changeover switch SW4. The individual terminal S13 of the changeover switch SW1 is connected to the individual terminal S41 of the changeover switch SW4,
The individual terminal S23 of the changeover switch SW2 is connected to the individual terminal S61 of the changeover switch SW6. Common terminal S1 of changeover switch SW1
1 and the individual terminal S12 are electrically connected, and when the individual terminal S31 and the common terminal S32 of the changeover switch SW3 are electrically connected, the signal given to the common terminal S11 of the changeover switch SW1 is connected to the magnetic head A.
recorded on magnetic tape via The common terminal S21 of the changeover switch SW2 and the individual terminal S22 are electrically connected, and the individual terminal S22 of the changeover switch SW4 is connected to the common terminal S21 of the changeover switch SW2.
41 and the common terminal S42, the signal applied to the common terminal S21 of the changeover switch SW2 is recorded on the magnetic tape by the magnetic head B.
The common terminal S11 and the individual terminal S13 of the changeover switch SW1 are electrically connected, and the changeover switch SW5
When the individual terminal S51 and the common terminal S52 are electrically connected, the signal applied to the common terminal S11 of the changeover switch SW1 is recorded on the magnetic tape by the magnetic head C. Common terminal S of changeover switch SW2
21 and the individual terminal S23 are electrically connected, and when the individual terminal S61 of the changeover switch SW6 and the common terminal S62 are electrically connected, the signal applied to the common terminal S21 of the changeover switch SW2 is recorded on the magnetic tape by the magnetic head D.

During playback, the signals recorded on the magnetic tape are read by one pair of magnetic heads A and B or the other magnetic heads C and D, and the magnetic head switching means
Given to SW. Magnetic head switching means SW
Now, the individual terminal S32 of the changeover switch SW3
is connected to the individual terminal S71 of the changeover switch SW7, the common terminal S32 of the changeover switch SW3 and the individual terminal S33 are electrically connected, and the individual terminal S71 of the changeover switch SW7 and the common terminal S
When 72 is made conductive, the signal read out by magnetic head A is applied to video amplifier 9. The individual terminal S43 of the changeover switch SW4 and the individual terminal S81 of the changeover switch SW8 are connected,
The common terminal S42 and the individual terminal S43 of the changeover switch SW4 are electrically connected, and the changeover switch SW8
When the individual terminal S81 and the common terminal S82 are electrically connected, the signal read by the magnetic head B is applied to the video amplifier 10. Changeover switch SW5
The individual terminal S53 of the switch SW7 is connected to the individual terminal S73 of the switch SW7, and the common terminal S5 of the switch SW5 is connected to the individual terminal S53.
When the individual terminal S73 of the changeover switch SW7 and the common terminal S72 are made conductive, the signal applied by the magnetic head C is applied to the video amplifier 9. Individual terminal S63 of changeover switch SW6
The individual terminal S83 of the changeover switch SW8 is connected to the common terminal S6 of the changeover switch SW6, and the individual terminal S63 is electrically connected to the common terminal S6 of the changeover switch SW6.
2 is made conductive, the signal read by the magnetic head D is applied to the video amplifier 10. The video amplifiers 9 and 10 are connected via level adjustment variable resistors R1 and R2 to make their output levels the same, and the output signal is given from the variable resistor R1 to a high pass filter (HPF) 11. Low pass filter (LPF) from variable resistor R2
given to 16. The signal amplified by the video amplifiers 9 and 10 and input to the high pass filter 11 is
The low frequency converted color signal component is cut off and given to the signal processing circuit 12 as an FM luminance signal. The FM luminance signal processed by the signal processing circuit 12 is supplied to an FM demodulation circuit 13 for FM demodulation, and then supplied to a video amplifier 14. The luminance signal applied to the video amplifier 14 is input to the mixing circuit 15. Amplified by video amplifiers 9 and 10 and passed through a low-pass filter 1
The high-frequency component of the signal inputted to 6 is cut off, and the signal is applied to a frequency conversion circuit 17 as a reproduced carrier color signal. The frequency-converted carrier color signal is amplified by the video amplifier 18 and input to the mixing circuit 15. The mixing circuit 15 mixes the luminance signal and the carrier color signal to form a video signal, which is applied to the output terminal T2.

Although not shown, the magnetic tape recording/reproducing apparatus has a servo mechanism for correctly controlling the rotational speed and phase of the magnetic heads A, B, C, and D. The servo mechanism includes a pulse generator 1 needed to detect the rotational speed and phase of the magnetic head.
9 is provided. According to the output pulse from this pulse generator 19, the changeover switch is
SW1 to SW8 are switched and operated as described later. The output of the pulse generator 19 matches the phase during recording, and is applied to a 90-degree phase shifter 20, and then applied to a flip-flop 21 with a 90-degree phase shift to the video amplifiers 9 and 10. Given. In response to the output from the 90 degree phase shift means 20, the flip-flop 21 operates the video amplifier 9 only when the reproduction signal is applied to the video amplifier 9, and operates the video amplifier 9 only when the reproduction signal is applied to the video amplifier 10. Activate the video amplifier 10.

The structures indicated by reference numerals 1 to 8 constitute recording signal creation means, and the structures indicated by reference numerals 9 to 18 and 21 constitute signal reading processing means.

FIG. 2 shows the cylinder head CH according to the invention.
The state in which magnetic heads A, B, C, and D are arranged is shown. Magnetic heads A and B are arranged at an interval of 180 degrees, and magnetic heads C and D are arranged at an interval of 180 degrees.
They are placed at 90 degrees offset from each other.

In FIG. 3, information is recorded on the magnetic tape MT. In FIG. 3, arrow A1 indicates the running direction of the tape, and arrow A2 indicates the scanning direction of the magnetic head. A video signal is recorded in the area T1 of the magnetic tape MT, and a control signal that follows the output pulse from the pulse generator 19 is recorded in the area D2. For example, the common terminal S1 of the changeover switch SW1 in FIG.
1 and the individual terminal S12 are electrically connected, the individual terminal S31 and the common terminal S32 of the changeover switch SW3 are electrically connected, and the common terminal S of the changeover switch SW2 is connected.
21 and the individual terminal S22 are electrically connected, and the individual terminal S41 and the common terminal S42 of the changeover switch SW4 are connected to each other.
When conductive, the pair of magnetic heads A and B record the applied video signal onto the magnetic tape MT. At this time, the magnetic head A is in the area T of the magnetic tape.
1, the magnetic tape MT is run in the direction of arrow A1, and the magnetic head is moved in the direction of arrow A1.
2, the magnetic head B scans the track TR2. In this way, video signals are sequentially recorded on tracks TR1, TR2, TR3, TR4, . . . . At this time, the common terminal S72 and the individual terminal S73 of the changeover switch SW7 in FIG. When the individual terminal S63 of the changeover switch SW6 and the common terminal S62 are electrically connected, video signals are reproduced from the magnetic heads C and D. Assuming that video signals have been recorded in advance on tracks TP1, TP2, TP3, etc., magnetic head A
When magnetic head A rotates 90 degrees after starting to scan track TR1, magnetic head C starts scanning track TR1.
Start scanning TP1. Magnetic head B tracks
When magnetic head B rotates 90 degrees after starting to scan TR2, magnetic head D starts scanning track TP2. In this way, while the magnetic heads A and B record the video signal, the magnetic heads C and D reproduce the previously recorded video signal. A pair of magnetic heads A and B are switched by switching the switches SW1 to SW8 of the head switching means SW.
It is also possible to reproduce the information using the magnetic heads C and D and record it using the pair of magnetic heads C and D. It is also possible to perform only recording or reproduction using only a pair of magnetic heads.

Effects As described above, according to the present invention, each pair of the first magnetic head and the second magnetic head are arranged on two mutually perpendicular diameter lines in the cylinder head. located between every other first group of tracks on the magnetic tape scanned by the first magnetic head and said first group of tracks on the magnetic tape scanned by the second magnetic head. Every other track of the second group can be used as two completely independent channels.

That is, two types of separate recording signals can be independently recorded on each group of the magnetic tape by the first magnetic head or the second magnetic head. Further, the signals recorded on the two groups of tracks on the magnetic tape can be independently read by the first magnetic head or the second magnetic head. Further, the first magnetic head can record recording signals on the first group of tracks on the magnetic tape, and the second magnetic head can read the signals recorded on the second group of tracks on the magnetic tape. Alternatively, the magnetic heads that perform the simultaneous recording and reading operations may be reversed. This greatly improves operability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram showing the states of magnetic heads A, B, C, and D arranged in cylinder CH, and FIG. 3 is a diagram showing the state of magnetic heads A, B, C, and D arranged in cylinder CH. FIG. 3 is a diagram showing a recorded state. A, B, C, D...Magnetic head, MT...Magnetic tape, SW...Head switching means.

Claims (1)

[Scope of Claims] 1. In a helical scanning type recording/reproducing device in which a rotating magnetic head scans a track diagonally with respect to the longitudinal direction of the magnetic tape, the magnetic tape is in sliding contact with the cylinder head within a range of approximately 180 degrees, A pair of first magnetic heads are disposed on the cylinder head in mutually symmetrical positions, and each second magnetic head of the pair is disposed on the cylinder head,
A recording signal that is arranged between each first magnetic head at equal intervals from each first magnetic head, and that creates a signal that is recorded on the magnetic tape via the first magnetic head or the second magnetic head. creating means; signal reading processing means for reading and processing signals from the magnetic tape via the first magnetic head or the second magnetic head; the first magnetic head and the second magnetic head;
A head switching means for connecting a recording signal generating means and a signal reading processing means, wherein a first magnetic head and a second magnetic head are connected to the recording signal generating means for each track, and the first magnetic head and the second magnetic head are connected to the recording signal generating means. A head that performs one of the following connection operations: connecting the magnetic head to the signal reading processing means for each track, and connecting the first magnetic head and the second magnetic head to either the recording signal creation means or the signal reading processing means for each track. What is claimed is: 1. A magnetic tape recording and reproducing device comprising: switching means.