JPH0661146B2 - Magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a video signal, an audio signal and a tracking signal on a video track on a magnetic tape such as an 8 mm video tape recorder (VTR). The present invention relates to a helical scan type video tape recorder for recording / reproducing a pilot signal for a television.

(Prior Art) Conventionally, in an 8 mm VTR, a tracking pilot signal is recorded by being superimposed on a video signal and an FM audio signal, and the tracking servo control is performed by reproducing this pilot signal.

(Problems to be solved by the invention) Therefore, when a new signal is inserted into a recorded tape (insert), the recorded track and the recording track to be inserted cannot be tracked, and the insertion start portion Even if the phase is adjusted with the recorded signal, there was a problem that the recorded track and the newly inserted recorded track would not be connected at the end of the insert due to the expansion and contraction of the magnetic tape, etc. in the insert for a long time. .

(Means for Solving Problems) In order to solve the above problems, the magnetic recording / reproducing apparatus of the present invention combines a video signal and a pilot signal having a different frequency between adjacent video tracks to record / reproduce. Magnetic recording / reproducing apparatus including a plurality of video heads, an erasing head that rotates at the same time as the video heads to erase information on a video track, and a dedicated tracking head mounted in a phase opposite to the erasing head by 180 degrees. Applied to
A first changeover switch for switching and outputting a pilot signal detected by the video head and a pulse generator output from a capstan PG servo, and on / off of a tracking error signal obtained by the tracking dedicated head. A second changeover switch for changing over, an output of the first changeover switch and the second changeover switch
The mixer which mixes the output of the selector switch and the output to the servo system and the first selector switch are connected to the video head side at the time of reproduction, and the recording signal is inserted at the time of recording and a part of the recorded tape. At the time of insertion, a switching control circuit for switching to the capstan PG servo side and for switching the second changeover switch to an on state at the time of insertion and an off state at the time of other modes is provided. When the head is running on the tape, the supply of the erasing current to the erasing head is stopped and the pilot signal is read from the recorded video track to perform tracking alignment between the recorded video track and the video head. To configure.

(Operation) At the time of insertion, the changeover control circuit connects the first changeover switch to the capstan PG servo side, outputs the pulse generator to the mixer, and turns on the second changeover switch to output the tracking error signal. Output to mixer. In the mixer, this pulse generator and the tracking error signal are mixed and sent to the servo system (capstan motor driver). As a result, it is possible to track the recorded track even though it is recording, and it is possible to connect the track even at the insert end portion.

In addition, the simple structure of stopping the supply of the erase current of the erase head when the dedicated tracking head is running on the tape allows the dedicated erase head to perform pilot erase from the recorded video track without being affected by the erase current. Can be read.

(Example) Hereinafter, the Example of this invention is described with reference to drawings.

1 and 2 are diagrams showing the positional relationship of each head used in the magnetic recording / reproducing apparatus according to the present invention.

In this example, two-channel video heads 1a and 1b are provided at opposite positions of the drum 4, and the erasing head 2 and the tracking dedicated head 3 are provided at positions orthogonal to these heads.
Are provided to face each other by 180 degrees. This erasing head 2
And the tracking dedicated head 3 is the video head 1
The head is designed to rotate with the rotation of a and 1b. The mounting heights of these heads are related as shown in FIG. That is, with the two video heads 1a and 1b having different azimuth angles as reference positions, the erasing head 2 has a height twice that of the video heads 1a and 1b, and erases two adjacent tracks. Further, the tracking dedicated head 3 is arranged above the erasing head 2 so as to trace one track before.

Due to the positional relationship of the heads, each head is
When the erasing head 2 does not hit the tape, that is, the tracking-specific head 3 is drawn, as shown in the figures (a) and (b).
Is running on the tape, the supply of the erasing current to the erasing head 2 is stopped, so that the dedicated tracking head 3 can read the pilot signal from the recorded track without being affected by the erasing current. [See FIGS. 4 (b) and 4 (c)].

FIG. 4 shows the timing of the head switching pulse, which is the switching timing of the video heads 1a and 1b, and the timing of the erasing current flowing in the erasing head 2 and the reproduction signal of the dedicated tracking head 3. In this example, a part of this reproduction signal is shown. Are sampled [see FIG. 4 (d)].

FIG. 5 is a block diagram showing the relationship between the above-described four heads and the servo system, and the changeover switch (first changeover switch) 5 is connected to the cap stun pulse generator (PG) servo side at the time of recording and inserting, At the time of reproduction, the pilot signals detected by the video heads 1a and 1b are sent to the head amplifier 6 and the low pass filter (LP).
It is input to the mixer 8 via F) 7 and sent to the servo circuit. In addition, a changeover switch (second changeover switch) 9
Sends the pilot signal detected by the tracking-dedicated head 3 to the servo circuit via the amplifier 10 and the LPF 11 during insertion. These changeover switches 5, 9
A system controller 12 configured by a microcomputer controls the above. Then, during insertion, the capstan PG servo 14 and the tracking dedicated head 3
The tracking error signal obtained by the above is mixed by the mixer 8 and sent to the capstan motor driver through the amplifier 13. For this reason, it is possible to perform tracking with a recorded track even during recording, and it is possible to connect even at the insert end portion. The fifth
In the figure, a pulse obtained from a capstan frequency generator (FG) servo 15 is also input to the mixer 8.

(Effect of the Invention) In the magnetic recording / reproducing apparatus of the present invention, the first control switch is switched to the capstan PG by the change control circuit at the time of insertion.
While connecting to the servo side to output the pulse generator to the mixer, the second changeover switch is turned on to output the tracking error signal to the mixer, and this mixer mixes the pulse generator and the tracking error signal to the servo system. Since it is configured to send out, the recorded track and the video head can be tracked while recording, and they can be completely connected even at the end of the insert. In addition, the simple structure of stopping the supply of the erase current of the erase head when the tracking dedicated head is running on the tape allows the tracking dedicated head to transmit the pilot signal from the recorded video track without being affected by the erase current. Can be read.

[Brief description of drawings]

FIG. 1 is a plan view showing the arrangement of magnetic heads used in a magnetic recording / reproducing apparatus according to the present invention, FIG. 2 is a view showing the arrangement of these heads in the height direction, and FIGS. 3 (a) and 3 (b). Is a diagram showing a track locus of each head, FIG. 4 is a timing chart showing operation timing of each head, and FIG. 5 is a block diagram showing a servo system. 1a, 1b ... Video head 2 ... Erase head 3 ... Tracking head

Claims (1)

[Claims] 1. A plurality of video heads for synthesizing and recording a video signal and pilot signals having different frequencies between adjacent video tracks, and rotating the video heads at the same time to erase information on the video tracks. Erase head,
In a magnetic recording / reproducing apparatus including a tracking dedicated head mounted at a position facing the erasing head by 180 degrees, a pilot signal detected by the video head and a pulse generator output from a capstan PG servo are switched. A first changeover switch for outputting the tracking error signal obtained by the dedicated tracking head, a second changeover switch for switching on / off the tracking error signal obtained by the tracking dedicated head, an output of the first changeover switch and a changeover of the second changeover switch. A mixer that mixes the output with the servo system and the first changeover switch is connected to the video head side at the time of reproduction, and the cap is used at the time of recording and when inserting a recording signal into a part of a recorded tape. Stan P
A switching control circuit is provided for switching to connect to the G servo side, and for switching the second switching switch to an ON state during insertion and an OFF state during other modes. When the vehicle is running, the supply of the erase current to the erase head is stopped and the pilot signal is read from the recorded video track to perform tracking alignment between the recorded video track and the video head. Magnetic recording / reproducing device.