JPS6129401A - Double cassette type vtr cylinder device - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution by using an amplifier substrate containing a reproduction amplifier circuit which amplifies the reproduction video signal sent from a video head at one side and delivers it to the other video head as a record video signal to a rotor. CONSTITUTION:An intermediate cylinder 23 unified with an attachment base 29 is set rotatably between upper and lower cylinders 21 and 22. A rotary shaft 24 containing cylinders 21-23 is pressed into the base 29 and fixed there. A pair of right and left video heads 25 and 26 are attached to the upper and lower stages at the end part of the base 29, and a disk-shaped amplifier substrate 5 is fixed at the center part of the base 29. A reproduction amplifier circuit is provided on the substrate 5, and the reproduction video signal sent from the head 25 is amplified via the reproduction amplifier circuit and then delivered to the other head 26 as a record video signal. This record signal is obtained just by amplifying the reproduction video signal. Then the circuit constitution is simplified since both an FM modulation circuit and an FM demodulation circuit can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides two tape cassettes (hereinafter referred to as cassettes) set in one VTR. This invention relates to a cylinder device for a double cassette VTR capable of dubbing, tape editing, etc.

(Prior art) Traditionally, two VTRs were required to perform videotape dubbing or tape editing, and there was a reluctance to purchase two VTRs, not just because of the installation space issue. There is.

In order to eliminate the above-mentioned problems, the applicant filed a U.S. Pat.
No. 248 discloses a VTR cylinder device having substantially the same configuration as the VTR cylinder device shown in FIG. 1 (7) of the present application. That is, inside the integrated guide cylinder (2),
A rotary body having video heads (c) and (a) projecting therein is housed in two upper and lower stages, and the video heads are made to emerge from slits provided at two upper and lower positions on the circumferential wall of the guide cylinder, respectively. Also, as shown in Figure 2, the guide cylinder (2)
Two cassette set attachment parts α and αB are arranged at different vertical heights corresponding to each video head, and two tape pull-out devices are placed around the outer periphery of the cylinder corresponding to the two-way set attachment parts. Deployed in two stages, upper and lower.

When a cassette is inserted into the dual force set mounting section and a loading operation is instructed, each tape drawer device rotates around the cylinder while drawing out the tape from the cassette, and as shown in Figs. 2 and 3, the tape +121 is placed in the cylinder. a:
Multiplying i is passing.

'With the above-mentioned VTR, one tape can be played back while the other tape can be used to record necessary parts, and one V'rR can perform dubbing or tape editing.

(Problem to be solved by the invention) However, in the above VTR, -1 one of the video heads (
If the coils of both video heads are simply connected directly to each other in order to output the video signal reproduced by (to) to the other video head (to) as a recording video signal, problems such as insufficient voltage of the reproduced signal will occur. Therefore, the reproduced signal is once led to the outside of the cylinder via the first rotary transformer connected to the first video head (c), and is then guided to the outside of the cylinder through an amplifier, a signal switching circuit using switching pulses, a luminance system/chroma system separation circuit, and a luminance system/chroma system separation circuit. It was necessary to generate a recording video signal through a system FM modulation circuit, a chroma system low-frequency conversion circuit, etc., and then return the video signal to the second video head (support) through a second rotary transformer. Therefore, the VTR cylinder not only requires two sets of rotary transformers, but also has the problem of complicating the electrical circuitry of the video signal processing system.

(Means for Solving the Problems) In order to solve the above problems, the present invention uses a rotating body of a VTR cylinder to amplify the reproduced video signal V from one video head device and send it to the other video head (support). It was equipped with an amplifier board (5) equipped with a reproducing amplifier circuit [Co., Ltd.] that outputs a recorded video signal W.

(Operation of the invention) The rotating body is rotationally driven by a power source such as a motor, and both video heads rotate together with the amplifier board (5). Two wound tapes for playback and recording are tracked simultaneously.

The video signal V played back from the playback tape by one video head (to) is amplified to a sufficient level by the playback amplifier circuit [Co., Ltd.], and becomes a recording video signal W to the other video head (support). Output to.

The video signal W is written onto a recording tape by the video head (support), and dubbing is performed.

(Effects of the Invention) In the VTR cylinder device according to the present invention, the amplifier board (5) mounted on the rotating body includes all the circuits for converting the reproduced video signal V into the recorded video signal W. Therefore, there is no need to guide the reproduced video signal V to the outside of the cylinder by means of a rotary transformer and perform various video signal processing, and only one set of rotary transformers is required, as is the case with ordinary rotary transformers used for reproduction and recording.

The amplifier board (5) may be equipped with a preamplifier used as a playback amplifier circuit when converting a playback video signal into a video signal in a general single cassette type VTR, and the above-mentioned chroma system low-frequency conversion. A video processing circuit such as a circuit is not required. Therefore, the circuit configuration is simple.

(Example) (a) Mechanical system A guide cylinder (2) is provided in the center of the VTR main body as shown in Fig. 2, and two cassette mounting parts (10) and (11) are placed between the cylinder (2). It is provided parallel to the chassis (1) and with different vertical heights corresponding to the tape width. Also, as shown in Figure 3, the guide cylinder (
2) Surrounding the tape drawer device +31 (
41 are deployed.

As shown in Fig. 1, the guide cylinder (2) is provided with a mounting base (2), which will be described later, between an upper cylinder (21) and a lower cylinder (2), which are coaxially positioned and fixed to each other by a connector T20+ and a bracket (20a). It has a rotatable intermediate cylinder (23+) integrated with the mark.

A rotating shaft is provided at the axis of each cylinder an@+231, and is press-fitted into the mounting base. A pair of left and right video heads ■■ and 06)@ are attached to the end of the mounting base in two stages, upper and lower, and the heads are located between the upper and lower cylinders t21J@ and the middle cylinder.

They are each coming out to the slit.

A disc-shaped amplifier board (5) is fixed to the center of the mounting base (to), and a regenerative amplifier circuit (53) is provided on the amplifier board (5).

The regenerative amplifier circuit (-) requires power supply and ground connection, as will be described later. For this reason, as shown in Figure 1, there is a power supply conductor (circle and ground conductor) inside the rotating shaft.
In both cases, a pair of conductor disks (541□□□) (thus, the regenerative amplifier circuit and Connect the conductor disc mark 6η of .A brush (
By contacting the cylinder (not shown), power can be supplied from the outside to the inside of the cylinder, or grounding can be established.

A rotary transformer surface is provided between the upper cylinder 121) and the mounting base 4, and the rotor (28a) and stator (28b) that constitute the cylinder motor (2) are installed between the lower cylinder (21) and the mounting base (4). Deployed.

Upper and lower video spatula) '1 (upper head (2 of 261)
) is for normal recording and playback, and the lower head (26) is used exclusively for dubbing and tape editing.

As shown in Fig. 2, the tape inlet part of the cylinder (2) (
2a), there is a full-width erase head (8) and a tape exit section (
2b), there is an audio erase head (81), an audio control head (821) and a capstan (8).
3) is in place.

The full-width erasing head (8) has a head chip (8a) for recording/reproducing cassette at the upper end and a head chip (8b) for dubbing cassette at the lower end as shown in FIG.
) are arranged corresponding to the height of the video head (251 (261), respectively, and both head chips (8a) (8b) are integrated with each other.
It is possible to accurately set the relative positions of a) and (8b). The audio erase head (g) 1) and the audio control head @ also have similar configurations.

The upper tape pull-out device (3), as shown in Fig. 3, has the same configuration as the previous tape pull-out device, and corresponds to the inclination of the guide cylinder (2) and has an upper tape mounting portion α1). It consists of an inclined loading ring (31) rotatably arranged so as to hang on the loading ring (31), and a biasing lever (31) that biases the tape pulled out by the loading ring (31J) toward the full-width erasing head (8). There is.

Inclined loading ring group) There is a pinch roller on top.
and multiple guide pin countries are deployed.

The lower tape pull-out device (4) includes a horizontal loading ring (41) that is parallel to the chassis (1) and rotatably arranged so as to hang on the lower tape mounting section (121), and a tape (41) pulled out by the loading ring. 12
1 to the capstan □□□ side.
43).

The guide cylinder (2) has a mounting base (support) formed separately from the intermediate cylinder (231) as shown in Fig. 9, and the intermediate cylinder (231) is connected to the upper cylinder (2°C and lower cylinder) by means of a connector. Of course, it is possible to configure it by integrating it with JL (support), and also other configurations
(b) Video signal processing circuit system The pair of left and right video heads (2) (25) installed on the top of the guide cylinder (2) is a rotary transformer as shown in Figure 5. It is connected to an image processing circuit (6) located outside the cylinder via the cylinder. As is well known, the video processing circuit (6) includes a preamplifier, a switching circuit,
It is composed of an FM equalization circuit, a dropout compensation circuit, a brightness processing circuit, a chroma processing circuit, etc., and an RF switching pulse is input as a control signal to the switching circuit from a servo circuit system, which will be described later. Video processing circuit (6
) output is connected to a monitor TV and displayed as an image.

The reproduced video signal V from the above-mentioned pair of video heaters (1) is branched within the cylinder and is input to a reproduced amplification circuit (transfer) provided on the amplifier board (5). As shown in the figure, the regenerative amplifier circuit consists of an equivalent amplifier ω (50), an impedance conversion amplifier 6υ (511), and a push-pull amplifier (521) connected in series. It has a circuit configuration similar to that of a preamplifier used when converting a The push-pull amplifier (5) is responsible for most of the amplification from the playback video signal V to the recording video signal W. The video signals W are respectively connected to video heads @ (a) for dubbing.

Since the rotational phase difference between the recording/playback video head □□□ and the dubbing-only video head (A) is zero, as shown in Figure 1, a signal switching circuit using RF switching pulses is installed on the amplifier board (5). is not necessary.

Furthermore, since the recorded video signal W can be obtained by simply amplifying the reproduced video signal Y, there is no need for a circuit for performing FM modulation or FM demodulation.

It should be noted that each of the above amplifiers (5B
This is done by using the conductor disks (56) @ fixed to the base end of the terminals as respective terminals.

(c) System control circuit system System control is performed by a microcomputer built into the VTR body. VTR of this example
has a dubbing key switch (not shown) on the operation panel, and when the switch is turned on and the input state of the microcomputer satisfies the following conditions, V
TR transitions to dubbing mode.

FIG. 8 shows a flowchart of the software written in the microcomputer. After the dubbing key switch is turned on, the cassette in switch installed on the VTR body inserts the cassette for playback and recording into the VT.
It is detected whether it is attached to R. If the dual power set is installed, it is then determined whether the tabs on the recording cassette to prevent accidental erasure are broken.

If the tab is broken, unload the recording cassette and set it to inject mode. When the claw is not broken, the mode changes to dubbing mode, and the cylinder motor,
A drive command is issued to the capstan motor, reel motor, etc. Therefore, the user can easily perform dubbing by simply operating the dubbing key switch, and there is no risk of accidentally erasing the cassette tape to be saved.

) In the servo circuit system dubbing mode, as shown in Figure 6, the cylinder motor (A) and capstan motor (8O1 are both 3
Servo is applied as described later by the reference pulse a of 0H2.

FIG. 7 shows waveforms at major locations in the block diagram of FIG. 6.

The rotation of the cylinder motor ■ is detected by the head rotation detector (to), and its detection signal is sent to the amplifier 176) (7).
6a) and is further input to the flip-flop surface to create an RF switching pulse C.

On the other hand, the reference pulse a is delayed by the delay circuit ffl+ to become an output d, and then input to the gate pulse generation circuit. The gate pulse e obtained from the gate pulse generation circuit a2 is input to the sample bold circuit,
The trapezoidal wave f created by inputting the RF switching pulse C to the trapezoidal wave generating circuit section is sampled as shown by the broken line in FIG. 7, and its value is held to create a head phase error voltage.

The error voltage is input to the mixing circuit (74). In addition, the mixing circuit (741) includes a speed control circuit rI consisting of a triangular wave generation circuit, etc., which generates the RF switching pulse C.
The head speed error voltage obtained by inputting it to gr is input and mixed with the head phase error voltage to create a head servo signal. The head servo signal is connected to the cylinder motor 2g+ to drive and control the motor.

The rotation of the cow Yapstan motor (801) is detected by a capstan rotation detector (98), inputted to the speed control circuit end consisting of a triangular wave generation circuit, etc. to create a capstan speed error voltage, and inputted to the mixing circuit MJnl. On the other hand, the reproduction control signal g detected by the reproduction side control head (91) is transmitted to the signal conversion circuit (
At 921, the signal is shaped into a pulse signal, and the control signal is output as a pulse signal.
A pulse h is created. The control pulse h passes through a delay circuit +931 (93a) and is converted from a signal i to a signal j. The signal j is inputted to a gate pulse generation circuit (961), the gate pulse obtained thereby is inputted to a sample hold circuit (961), and the reference pulse a is inputted to a trapezoidal wave generation circuit ((5), The captured trapezoidal wave l is sampled as shown by the broken line in Figure 7, and its value is held to create a capstan phase error voltage.The phase error voltage is input to the mixing circuit (supply), and the capstan phase error voltage is The capstan servo signal is mixed with the speed error voltage to create a capstan servo signal, which is connected to the capstan motor to drive and control the motor.

A recording control signal n having a predetermined duty obtained by inputting a reference pulse a to a monostable multi-channel (9) is connected to the control head on the recording tape side.

With the configuration of the servo circuit, the reproduction control signal, the recording control signal, and the vertical synchronization signal of the reproduction video signal are all servoed using the reference pulse a as a medium. Therefore, the conventional single cassette type VTR
It is possible to configure the circuit system shown in Figure 6 by simply adding some switch means and one monostable multi (9) to the servo circuit in Figure 6. There is no need to provide a dedicated servo circuit. As a result, the circuit configuration becomes simple.

Although the double cassette type VTR cylinder device according to the present invention has an effective function that allows dubbing to be performed with one VTR, the circuit configuration and number of parts are almost the same as in the conventional single cassette type VTR. It has excellent effects such as no difference in performance and ease of operation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a VTR cylinder device according to the present invention;
Figure 2 is a plan view of the tape being pulled out, Figure 3 is a front view of the cylinder and tape pull-out device, Figure 4 is a perspective view of the full-width erasing head, Figure 5 is a block diagram of the video signal processing circuit system, Figure 6 is a block diagram of the servo circuit system, Figure 7
The figure is a timing chart for the block diagram in Figure 6,
Figure 8 is a system control flowchart, Figure 9
The figure is a sectional view showing another embodiment. (2)...Guide cylinder (to) ■...Video head (5)...Amplifier board [Co., Ltd.]...Reproduction amplifier circuit

Claims (2)

[Claims] (1) A VTR cylinder device comprising a rotary body with video heads (25) and (26) protruding from two stages above and below, and a guide cylinder (2) on the same axis around which a magnetic tape is wound. In the rotating body, one video head (2
5) is characterized in that an amplifier board (5) equipped with a reproduction amplification circuit (53) for amplifying the reproduction video signal V from the video head (26) and outputting it as a recording video signal W to the other video head (26) is fixed. Double cassette type VTR cylinder device. (2) The regenerative amplifier circuit (53) includes an equivalent amplifier (50) that corrects the frequency characteristics of the reproduced video signal V, an impedance conversion amplifier (51) that includes a common base circuit, and a push-pull amplifier (52). A VTR cylinder device according to claim 1, which is connected in series.