JPH0770108B2 - Rotating cylinder type magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cylinder type magnetic recording / reproducing apparatus provided with a magnetic head switching means on a rotary cylinder.

2. Description of the Related Art In a conventional rotary cylinder type magnetic recording / reproducing apparatus, two magnetic heads mounted on the rotary cylinder and having a positional relationship of approximately 180 ° with each other are switched every half rotation of the rotary cylinder as in a VHS system VTR, for example. Recording or playback is performed. The switching for each half rotation (hereinafter referred to as 180 ° switching) is performed on the main body side. On the other hand, signal transmission between each head on the rotary cylinder and the main body side circuit is performed through a transmission path by a rotary transformer provided for each head.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in a high-definition VTR or a digital VTR, the amount of information to be recorded is large, and when 1-channel recording is performed, the relative speed of the tape head increases, which is disadvantageous in the life of the head and the cylinder bearing. Therefore, it is necessary to record on multiple channels, and a commercial VT that enables editing and simultaneous playback
In R and the like, a pre-reproduction head and a simultaneous reproduction head are required, the number of magnetic heads is further increased, and a large number of rotary transformer transmission lines are required, resulting in a complicated cylinder configuration.

Therefore, it is a technical object of the present invention to reduce the number of transmission lines between the main body side and the rotary cylinder side and to simplify the structure of the cylinder.

MEANS FOR SOLVING THE PROBLEMS The present invention provides an electromagnetic conversion means composed of at least two magnetic heads, one pair of two magnetic heads mounted symmetrically from the center on the rotary cylinder, and an electromagnetic conversion means on the rotary cylinder. 180 ° switching means for switching the two magnetic heads of each set of the electromagnetic conversion means for every 180 °, and a recording signal and a reproduction signal provided from the main body as a signal transmission path between the main body side and the rotating cylinder. A rotary transformer that transmits the 180 ° switching means to or from the 180 ° switching means to the main body, a serial transmission means that serially transmits a switching timing signal of the 180 ° switching means from the main body side to the rotating cylinder, and the serial transmission means. A serial-paper that creates individual 180 ° switching signals corresponding to each set of magnetic heads on the rotating cylinder from the output signal. And a parallel conversion means, the serial-parallel conversion means includes an N-stage shift register corresponding to N sets of magnetic heads, and the N-stage shift register clears cylinder rotation phase information obtained from a rotation cylinder phase detection unit. The input signal, 180 ° switching timing information of each magnetic head set obtained from the serial transmission means is used as a clock input signal, and the inverted output signal of the final stage of the shift register is used as the input signal of the first stage of the shift register. To do.

As described above, according to the present invention, the N-stage shift register operates with the 180 ° switching timing information of each magnetic head set obtained from the serial transmission means as a clock, and the inverted output of the shift register becomes the input signal of the shift register. ,
The shift register generates a rectangular wave of 1 / 2N of the clock frequency, and the rectangular wave is phase-synchronized with the rotation of the cylinder by the clear input signal. By using the head switching signal generated in this way, the two magnetic heads of each set of the electromagnetic conversion means are switched by 180 ° switching means on the rotary cylinder every 180 ° for recording or reproduction. Therefore, the transmission path for the recording signal or the reproducing signal between the rotary cylinder side and the main body side is sufficient only by the number of magnetic heads including the two magnetic heads of the electromagnetic conversion means. Further, a switching timing signal for switching two magnetic heads of each set at every 180 ° is transmitted from the main body side to the rotary cylinder side through one transmission line by the serial transmission means, and the electromagnetic conversion means by the serial-parallel conversion means. Is used as a 180 ° switching signal required for each set of.

Embodiments (1) The invention of claim 1 of the present application realizes a rotary cylinder type magnetic recording / reproducing apparatus having a simple cylinder configuration by reducing the number of digital transmission paths between the main body side and the rotary cylinder side.

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing the configuration of this embodiment, and FIG. 2 is an arrangement diagram showing the arrangement of a magnetic head, phototransistors, etc. on a rotary cylinder. In this embodiment, the effective tape winding angle is about 180 °, and four magnetic heads 6, 7, 8 and 9 are arranged as shown in FIG. 2 in a VTR of one channel recording. Now, the input video signal applied from the input terminal 0 is given to the recording side signal processing section 1. The recording-side signal processing unit 1 quantizes the input signal, adds shuffling and error correction parity, and adds and modulates SYNC and ID. At the time of recording, the image signal passes through one transmission path of the rotary transformer 2 and is a REC 18 which is one of the 180 ° switching means on the rotating cylinder side.
It is applied to the 0 ° SW unit 3, and a sync signal is applied to the servo system controller 14. The servo / sys-con unit 14 controls the cylinders, capstans, etc. as well as the conventional VTR and VTR system control, and also generates a magnetic head 180 ° switching timing signal as shown in FIG. 4A. The signal passes through the optical coupling section 15 which is a transmission means, and S / which is a serial-parallel conversion means.
It is added to the P conversion unit 17. The optical coupling portion 15 is composed of an LED 22 and a phototransistor 23 provided on the axis of the rotary cylinder 24 shown in FIG. 2 (a). On the other hand, the rotary cylinder phase detector 16 has an LED 25 on the main body side and a phototransistor 26 on the rotary cylinder that are constantly lit, as shown in FIG. The rotation of the rotary cylinder 24 causes the phototransistor 26 to generate a negative pulse as shown by the waveform B in FIG. 4 every time the phototransistor 26 passes the position of the LED 25.

Next, as shown in FIG. 3, the S / P converter 17 inverts the output signals of the number of stages corresponding to the number of sets of heads, that is, the shift register 32 of two stages and the output signal of the final stage in the present embodiment, and shifts to the shift register 32. It is composed of an inverter 33 for giving. Shift register
An input terminal 30 of 32 is a terminal for inputting a timing signal such as the waveform A from the optical coupling section 15 as a clock, and an input terminal 31 is a fourth terminal from the rotary cylinder phase detection section 16.
This is a terminal for inputting a negative pulse signal such as the waveform B in the figure as a clear signal. In addition, the output terminals 34 and 35 each have a fourth
As shown in the waveforms Q1 and Q2, two signals with the duty of 50% and the same period and different phases by 90 ° are output. This signal is a terminal from which a 180 ° switching signal for each set of magnetic heads is output.
Added to ° SW section 3 and PB180 ° SW section 13. At the time of recording, the recording side signal processing unit 1 applies a recording signal to the REC 180 ° SW unit 3 via the rotary transformer 2, and the REC 180 ° SW unit 3 switches the recording signal by a switching signal such as the waveform Q1 in FIG. The magnetic heads 6 and 7 are alternately added to the recording amplifiers 4 and 5, and the magnetic heads 6 and 7 alternately record the recording signal every half rotation of the rotary cylinder, similarly to the conventional 180 ° switching of the VTR.

Next, on the reproducing side, the reproducing head amplifiers 11 and 12 are always connected to the magnetic heads 8 and 9, respectively, and the reproducing head amplifiers 11 and 12 are switched in the PB 180 ° SW section 13 by the 180 ° switching signal such as the waveform Q2 in FIG. The effective one is selected from the respective output signals of and is transmitted to the reproduction side signal processing unit 20 via the rotary transformer 2. SY on the playback side signal processor 20
Various processes such as NC and ID detection, error correction, deshuffling, and correction are performed, and a reproduced video signal is output to the output terminal 21. The power supply unit 18 and the rectification unit 19 are for supplying the power necessary for forming an active circuit in the rotary cylinder.

As described above, in the present embodiment, the signal transmission path for recording or reproduction on the main body side and the rotating cylinder side is reduced to half the number of heads, so that the signal transmission rotary transformer can be constructed in a small size, and the cylinder construction is easy. Has the effect of becoming. In this embodiment, the VTR for 1-channel recording is explained so as not to complicate the description.
The effect of the present invention increases as the number of magnetic heads mounted on the rotary cylinder increases, such as a VTR that performs multi-channel recording such as a TR or D2 digital VTR.

Although optical coupling is used in the construction of the serial transmission means in this embodiment, a slip ring or a rotary transformer may be used instead.

(2) An object of the present invention is to make the cylinder configuration easier than that of the first embodiment by making the serial-parallel conversion means of the first embodiment unnecessary for the rotary cylinder phase detector 16. There is.

According to the present invention, the serial transmission means of the first embodiment transmits from the main body side to the rotary cylinder as a signal in which 180 ° switching timing information of each magnetic head set and cylinder rotation phase information are superimposed. Example serial-
The parallel conversion means includes a separator for separating the signal given by the serial transmission from the cylinder rotation phase information and the 180 ° switching timing information of each set of magnetic heads, and an N-stage shift register corresponding to the number N of sets of magnetic heads. It is replaced with a serial-parallel conversion means configured to include it. The N-stage shift register uses the cylinder rotation phase information of the separator output signal as a clear input signal, the 180 ° switching timing information of each magnetic head set as a clock input signal, and the inverted output signal of the final stage as the input of the first stage. It is configured as a signal.

The more specific configuration and operation will be described below. In the block diagram of FIG. 1, the rotary cylinder rotary phase detector
Others are the same except that 16 is unnecessary, and the description will be given based on FIG. The cylinder rotation phase information is 180 for each set of magnetic heads.
Servo system controller with switching timing information
It is added from 14 to the optical coupling section 15 which is a serial transmission means. In the optical coupling unit 15, the pulse width for selecting the magnetic head 9 shown by the broken line in the 180 ° switching timing information based on the cylinder rotation phase information is expanded four times as shown in FIG. Is being transmitted to. In this way, the rough cylinder rotation phase information and the 180 ° switching timing information of each set of magnetic heads are superimposed and transmitted to the rotary cylinder 24. This signal is applied to the serial-parallel conversion means shown in FIG. The same means is composed of a separator and a two-stage shift register 44. The separator is a monostable multivibrator (MM) to which the input signal is given.
41 and a delay circuit (DL) 42 having a constant delay time and a gate 43 to which these outputs are given. The monostable multivibrator 41 outputs a signal of a constant width at the rising edge of the input signal, and its output pulse width is 180
° Switching timing information Pulse width Th is set to twice. The delay circuit 42 is set to twice the delay time Δt of the monostable multivibrator 41. The output of the monostable multivibrator 41 is given to the shift register 44 as a shift signal, and the output of the gate circuit 43 is given as a clear signal. The shift register 44, like the shift register 33 of the first embodiment described above, has N head sets of rotating cylinders.
A 2-bit shift register corresponding to (two sets in this embodiment), the outputs of which are REC 180 ° SW unit 3 and PB18, respectively.
0 ° given to SW unit 13. The inverted output of the final output stage of the shift register 44 is applied to the input terminal D of the shift register 44.

Next, the operation of this serial-parallel conversion means will be described with reference to FIG. Fig. 6 Waveform C on input terminal 40
A monostable multivibrator when a signal such as
The output shown in FIG. 6A is obtained from 41. When the output of the monostable multivibrator is at the low level and the output of the delay circuit 42 is at the high level, the gate 43 outputs the low level as shown by the waveform B in FIG. 6 to clear the shift register 44. Since the inverting output terminal of the final stage of the shift register 44 is given as the input of the first stage, the clock input of the shift register 44 is input to the output terminals 45 and 46 like the waveforms Q1 and Q2 of FIG. 6 as in the first embodiment. 18 for each set of magnetic head divided by 1 / 2N of waveform A
A 0 ° switching signal is output.

As described above, according to this embodiment, 180 ° of each set of magnetic heads
By superimposing the rough cylinder rotation phase on the switching timing information by pulse width modulation and transmitting it serially on one channel, it is possible to accurately perform 18 bits for each set of magnetic heads without providing a rotation cylinder rotation phase detection unit on the rotation cylinder.
There is an effect that a 0 ° switching signal can be created and the cylinder configuration becomes easier.

As described above, according to the inventions of claims 1 and 2 of the present application, since the transmission lines between the main body side and the rotary cylinder side can be reduced as described above, the rotary cylinder type magnetic recording / reproducing with a simple cylinder configuration is possible. There is an effect that the device can be realized. The effect also increases as the number of heads mounted on the rotating cylinder increases.

[Brief description of drawings]

FIG. 1 is a block diagram of this embodiment, and FIG. 2 (a) is a side view of the cylinder showing the arrangement of a magnetic head and the arrangement of a phototransistor and a light emitting diode on a rotary cylinder in the first embodiment, and FIG. (B) is a top view thereof, FIG. 3 is a concrete block diagram of the S / P converter 17 of the first embodiment, FIG. 4 is a waveform diagram for explaining the first embodiment, and FIG. Is a concrete block diagram of the serial-parallel conversion means of the second embodiment, and FIG. 6 is a waveform diagram for explaining the second embodiment. 1 ... Recording side signal processing unit, 2 ... Rotary transformer,
3 …… REC 180 ° SW part, 4,5 …… Recording amplifier, 6,7 …… Recording head, 8,9 …… Playback head, 10 …… Tape, 11,12 ……
Playback head amplifier, 13 …… PB 180 ° SW section, 14 …… Servo / syscon section, 15 …… Optical coupling section, 16 …… Rotating cylinder phase detection section, 17 …… S / P conversion section, 18 …… Power supply Department, 19 ...
… Rectifier, 20 …… Reproduction side signal processor, 22,25 …… LED, 2
3,26 …… Phototransistor, 24 …… Rotating cylinder, 3
2,44 …… Shift register, 41 …… Monostable multivibrator, 42 …… Delay circuit.

Claims (2)

[Claims] 1. An electromagnetic conversion means comprising at least two magnetic heads, one pair of two magnetic heads mounted symmetrically from the center of a rotary cylinder, and an electromagnetic converter provided on the rotary cylinder. A 180 ° switching means for switching the two magnetic heads of each set of the conversion means at every 180 °, and a recording signal and a reproduction signal provided as a signal transmission path between the main body side and the rotating cylinder from the main body by the 180 ° switching means. Or a rotary transformer for transmitting from the 180 ° switching means to the main body, a serial transmission means for serially transmitting the switching timing signal of the 180 ° switching means from the main body side to the rotary cylinder, and a rotary cylinder from the output signal of the serial transmission means. And serial-parallel conversion means for creating individual 180 ° switching signals corresponding to each set of magnetic heads. And the serial-parallel conversion means has a number N of magnetic head sets.
The same number of N-stage shift registers are included. The N-stage shift registers use the cylinder rotation phase information obtained from the rotation cylinder phase detection unit as a clear input signal, and the magnetic head each set 180 ° switching timing information obtained from the serial transmission means. Is a clock input signal, and an inverted output signal of the final stage of the shift register is an input signal of the first stage of the shift register. 2. The serial transmission means comprises 180 for each set of magnetic heads.
° A signal in which the switching timing information and the cylinder rotation phase information are superimposed is transmitted from the main body side to the rotating cylinder, and the serial-parallel conversion means receives the cylinder rotation phase information and the magnetic field from the signal given from the serial transmission means. The rotary cylinder type magnetic recording / reproducing apparatus according to claim 1, further comprising a separator for separating 180 ° switching timing information of each set of heads.