JP2618537B2 - Broadcast system control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PAL system and an NTSC system.
The present invention relates to a broadcast system control circuit of a magnetic recording / reproducing apparatus capable of recording and reproducing a plurality of color television signals of different broadcasting systems such as a system, and more particularly, to a PBCTL signal and a capstan FG recorded on a magnetic tape during reproduction. The present invention relates to a broadcast system control circuit that determines the type of a broadcast system of a color television signal recorded on a magnetic tape using the signals and controls a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art There are various types of color television signal broadcasting systems, such as the NTSC system employed in Japan and the United States and the PAL system employed in the United Kingdom and Italy. Are not compatible with each other. Therefore, in general, VTR (Video Ta)
A magnetic recording / reproducing device such as a pe recorder is set to an operation mode in which signal processing corresponding to a broadcasting system in each region can be performed.

However, a magnetic recording / reproducing apparatus that processes signals only in a specific broadcast system cannot reproduce a magnetic tape recorded in a broadcast system different from the set state, and thus its use is restricted. In particular, recently, the movement of people and things has become active due to the development of means of transportation and the like, and magnetic tapes recording color television signals of different broadcasting systems are often reproduced. Has become a big problem.

Therefore, in order to greatly expand the usable range of the magnetic recording / reproducing apparatus, there is a model having an operation mode capable of recording and reproducing a plurality of color television signals of different broadcasting systems. When the reproduction is performed by the reproducing device, the broadcasting system of the color television signal recorded on the magnetic tape is determined, and the operation mode of the magnetic recording and reproducing device is set to correspond to the determined broadcasting system. .

Normally, the above-described discrimination and control at the time of reproduction are performed by:
This is implemented by a broadcast system control circuit. The broadcast system control circuit includes a PBCT recorded on a magnetic tape.
A signal input circuit for reproducing the L signal and the capstan FG signal; and a PAL determination signal and an N signal based on the two signals.
It has a PAL / NTSC discrimination circuit that outputs a TSC discrimination signal, and a servo control circuit that controls a servo circuit with a discrimination signal from the PAL / NTSC discrimination circuit (see FIG. 2).

Conventionally, as shown in FIG. 3, the above-mentioned broadcast system control circuit determines whether or not a magnetic tape is being loaded (S11). A mode initialization signal is output to initialize the magnetic recording / reproducing apparatus to an operation mode compatible with the PAL system (S12).

On the other hand, if no loading is being performed, N
It is determined whether loading is completed as O (S1).
3) If the loading has not been completed, NO is initially set to the PAL mode of operation described above (S1).
2 is executed. Thereafter, when the loading is completed, the data which is the result of the discrimination by the PAL / NTSC discriminating circuit is output as a discrimination signal as YES, and the operation mode corresponding to the broadcasting system of the discrimination signal is set. (S14).

As a result, the conventional broadcast system control circuit has:
Since the broadcasting system of the color television signal recorded on the magnetic tape is determined, and the magnetic recording / reproducing apparatus is set to an operation mode corresponding to the determined broadcasting system, there is no need to check the broadcasting system at the time of reproduction. The operation of the playback device can be facilitated.

[0009]

However, in the conventional broadcasting system control circuit, when the broadcasting system of the color television signal recorded on the magnetic tape is the NTSC system, it always takes a long time to start reproduction. There is a problem.

In other words, the conventional broadcast system control circuit initially sets the operation mode of the magnetic recording / reproducing apparatus to the PAL system until the loading is completed, so that the color television signal recorded on the magnetic tape can be read. When the broadcasting system is the NTSC system, it is necessary to change the setting from the initially set operation mode of the PAL system to the operation mode of the NTSC system.
The time is longer than in the case of the method. When the operation mode is changed from the PAL system to the NTSC system, the initialization to the PAL system is performed for each loading, so that it always takes a long time to start the reproduction.

Accordingly, the present invention provides a broadcast system control circuit capable of shortening the time required to start reproduction by maintaining the operation mode of the broadcast system determined after inserting the cassette. The purpose is.

[0012]

In order to solve the above-mentioned problems, a broadcast system control circuit according to the present invention is a magnetic system capable of recording and reproducing color television signals of a plurality of different broadcast systems such as a PAL system and an NTSC system. A broadcast system control circuit that is provided in the recording / reproducing device and that determines a broadcasting system of a color television signal recorded on a magnetic tape of an inserted cassette and sets the magnetic recording / reproducing device to the determined broadcasting system. , The broadcast system control circuit has a signal input circuit, a PAL / NTSC discrimination circuit, and a servo control circuit serving as a discrimination result storage setting means, and the servo control circuit includes a cassette inserted into the magnetic recording / reproducing apparatus.
The broadcasting system first determined by the above discrimination circuit
Is stored, and the cassette is read from the magnetic recording / reproducing device.
If a playback operation is performed before the
Set the magnetic recording / reproducing device based on the above broadcasting system
It is characterized in that.

[0013]

According to the above arrangement, the discrimination result storage setting means sets the magnetic recording / reproducing apparatus to the broadcast system of the first discriminated color television signal after the cassette is inserted until the cassette is removed. It has become. Therefore,
After playing once, play the stopped cassette again.
In this case , the broadcast system control circuit determines that the broadcast system is immediately recorded on the magnetic tape without discriminating the broadcast system.
To thereby set the magnetic recording and reproducing apparatus in the same broadcast system
You . Thus, once the cassette is inserted and played back, the broadcast system control circuit does not need to perform the operation of determining the broadcast system, and the time required for stabilizing the rotation speed of the capstan motor when switching the broadcast system, for example. Is unnecessary, so that the time required for starting the reproduction of the color television signal can be reduced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The broadcasting system control circuit according to the present embodiment has a configuration shown in FIG.
As shown in FIG. 1, a broadcasting system control circuit including a signal input circuit 1, a PAL / NTSC discriminating circuit 2, and a servo control circuit 3 includes a PAL system and an NTSC system. Etc. are provided in a magnetic recording and reproducing apparatus capable of recording and reproducing a color television signal of a plurality of broadcasting systems.

The signal input circuit 1 has a magnetic head 5 for reproducing a PBCTL signal recorded on a magnetic tape 4, and this magnetic head 5 is connected to an amplifier circuit 8 for amplifying the PBCTL signal. Have been. The signal input circuit 1 is also provided with an amplifier circuit 7 for amplifying a signal, similarly to the amplifier circuit 8 described above. The amplifier circuit 7 includes a capstan FG head 6 for outputting a capstan FG signal. Is connected. The capstan FG head 6 outputs a capstan FG signal from a capstan motor 9 so that the capstan motor 9 determines the traveling speed and traveling direction of the magnetic tape 4. Has become.

The amplifier circuit 7 to which the capstan FG signal is input from the capstan FG head 6 is a PAL
/ NTSC determination circuit 2 is connected to the count register circuit 10, and the count register circuit 10
It is connected to the comparison circuit 11 for L / NTSC discrimination. The counting register circuit 10 integrates the capstan FG signal input via the amplifier circuit 7 and outputs the integrated value to the PAL / NTSC discriminating comparison circuit 11.

Further, PAL /
The NTSC discriminating comparison circuit 11 includes the magnetic head 5 described above.
Is also connected, and the PAL / NTSC discriminating comparison circuit 11 receives the PBCTL signal via the amplifier circuit 8 when the PBCTL signal is input through the amplifier circuit 8.
While the integrated value from the count register circuit 10 is taken in, the count register circuit 1
The integrated value of 0 is cleared. And
The PAL / NTSC discriminating comparison circuit 11 compares the integrated value, which is the input interval of the PBCTL signal, with a predetermined set value to determine whether the color television signal recorded on the magnetic tape 4 is of the PAL system or NTSC. System, and a PAL determination signal or NTS
A C determination signal is output.

A PAL / PAL having the counting register circuit 10 and the PAL / NTSC discriminating comparison circuit 11 is provided.
The NTSC discrimination circuit 2 is connected to a servo control circuit 3 which is a discrimination result storage setting means. The servo control circuit 3 has a mode discrimination circuit 12 and a servo control register circuit 13. The mode discrimination circuit 12 includes the PAL / NTSC discrimination comparison circuit 11 of the PAL / NTSC discrimination circuit 2 described above. Connected, PAL determination signal and NTS
The C discrimination signal is input.

The above-mentioned mode discriminating circuit 12 carries out the above-mentioned PAL discriminating signal and N based on a mode discriminating routine which will be described later.
A discrimination signal composed of a TSC discrimination signal and a PAL mode initialization signal are output. The initial setting signal is set to the PAL system operation mode of the magnetic recording / reproducing apparatus, and is output at the first loading after the cassette is inserted into the magnetic recording / reproducing apparatus. I have.

The mode discriminating circuit 12 is connected to a servo control register circuit 13. The servo control register circuit 13 uses a discrimination signal and an initial setting signal input from the mode discriminating circuit 12 in a PAL system. And NTSC
A servo control signal corresponding to the system is output. Then, the servo control register circuit 13
The capstan motor 9 is connected to a servo circuit 14 for stably rotating the capstan motor 9.
By controlling the rotation speed or the like according to the servo control signal, the magnetic recording / reproducing apparatus is set to an operation mode of the PAL system and the NTSC system.

In the above configuration, the operation of the broadcast system control circuit will be described with reference to the flowchart of FIG.

First, when a cassette accommodating the magnetic tape 4 is inserted into the magnetic recording / reproducing apparatus and a reproduction button (not shown) is pressed, the magnetic tape 4 is pulled out from the cassette and loading is started. At this time, the servo control circuit 3 executes the mode determination routine shown in FIG. 1, and determines whether the magnetic tape 4 is being loaded (S1).

If it is determined in the above S1 that loading is being performed, S2 is executed as YES, and
It is determined whether the current loading is the first loading after the insertion of the cassette (S2). Since the current loading is the first loading after the cassette is inserted, S3 is executed as YES, and the PAL mode initialization signal is output from the mode determination circuit 12 to the servo control register circuit 13. Will be. As a result, the servo control register circuit 13 outputs a servo control signal corresponding to the PAL method to the servo circuit 14 to rotate the capstan motor 9,
The magnetic recording / reproducing apparatus is set to the PAL operation mode (S3).

Next, the loading is completed and the above PA
When the reproduction is started in the L mode operation mode, a PBCTL signal is output from the magnetic tape 4 via the magnetic head 5, and the PBCTL signal is amplified to a predetermined voltage level by the amplifier circuit 8. After PAL / NT
PAL / NTSC discriminating comparison circuit 11 of SC discriminating circuit 2
Will be output to

When the loading is completed, a capstan FG signal of a pulse number corresponding to the rotation of the capstan motor 9 is input to the amplifier circuit 7 via the capstan FG head 6, and this capstan FG
The signal is amplified to a predetermined voltage level by the amplifier circuit 7, and then output to the counting register circuit 10 of the PAL / NTSC discriminating circuit 2.

The capstan FG signal input to the count register circuit 10 is integrated by the count register circuit 10, and the integrated value is PAL.
/ NTSC is output to the comparison circuit 11 for discrimination. Then, the PAL / NTSC discriminating comparison circuit 11 to which the integrated value and the above-described PBCTL signal are input,
The servo control circuit determines whether the color television signal recorded on the magnetic tape 4 is of the PAL system or the NTSC system by taking in the integrated value for each input of the CTL signal and comparing it with a predetermined set value. 3 mode discriminating circuit 12
Then, a PAL discrimination signal or an NTSC discrimination signal, which is a discrimination signal, is output.

At this time, the mode discriminating circuit 12 to which the above discriminating signal has been input determines that loading is not being performed in S1, and executes NO in S4, and determines whether or not loading is completed. (S
4). Then, by determining that the loading is completed in S4, S5 is executed as YES, and
The mode discrimination circuit 12 outputs the discrimination signal input from the PAL / NTSC discrimination circuit 2 to the mode discrimination circuit 12 to the servo control register circuit 13, and stores the data of the discrimination signal in the register (S5).

Thus, the servo control register circuit 1
When the color television signal recorded on the magnetic tape 4 is of the PAL system, a servo control signal corresponding to the PAL system is output to the servo circuit 14 to rotate the capstan motor 9 and the initially set PAL. The magnetic recording / reproducing apparatus is operated in the operation mode of the system. On the other hand, if the color television signal is in the NTSC system, N
Servo control signal corresponding to the TSC system is sent to the servo circuit 14.
And the capstan motor 9 is rotated, and the magnetic recording / reproducing apparatus initialized to the PAL mode is set to N.
The operation mode will be changed to the TSC mode.

Next, when the magnetic recording / reproducing apparatus is stopped, the capstan motor 9 is stopped and the magnetic tape 4 is unloaded. At this time, in the servo control circuit 3, the mode determination routine is continuously executed, and after it is determined that the loading is not performed (S1), it is further determined that the loading is not completed in S4 (S4), and the process is ended as NO. Will be done. As a result, the servo control register circuit 13
Means that the data of the first discrimination signal when the cassette is inserted is stored by holding the storage state of the register, and this data is stored by removing the cassette from the magnetic recording / reproducing apparatus and inserting the cassette again. Then, it is maintained until S5 is executed.

Next, when the magnetic recording / reproducing apparatus is reproduced again from the above-mentioned stopped state, it is determined in S1 that loading is being performed, and S2 is executed as YES. Then, in this S2, it is determined that the current reproduction is not the first loading after the insertion of the cassette, and the mode determination routine is ended as NO, and the servo control register circuit 13 reads the previously recorded register. The servo control signal corresponding to the data is output to the servo circuit 14 to rotate the capstan motor 9 and set the operation mode of the magnetic recording / reproducing apparatus.

As described above, the broadcast system control circuit of the present embodiment holds the contents of the register of the servo control register circuit 13 at least until the cassette is removed, and when reproducing from the stopped state, changes the broadcast system. The operation mode of the capstan motor 9 and the like is immediately set by the data of the register without discrimination. Therefore, this broadcast system control circuit does not require the operation of discriminating the broadcast system once reproduced, and also eliminates the time required for stabilizing the servo circuit 14 when switching the broadcast system. It is possible to shorten the time required for starting the reproduction of the television signal.

In this embodiment, the broadcast system control circuit is used for controlling the capstan motor 9. However, the present invention is not limited to this. It may be used for setting and controlling other necessary circuit systems and mechanism systems.

[0034]

As described above, the broadcasting system control circuit of the present invention is provided in a magnetic recording / reproducing apparatus capable of recording and reproducing a plurality of color television signals of different broadcasting systems, and is provided on a magnetic tape of an inserted cassette. In a broadcast system control circuit having a circuit for determining a broadcast system of a recorded color television signal, a cassette is inserted into a magnetic recording / reproducing apparatus.
After being input, the broadcasting method first determined by the above-mentioned determination circuit
A determination result storage setting means for storing the expression;
The result storage setting means further comprises:
When a playback operation is performed before disconnecting from the device
Is a magnetic recording / reproducing method based on the stored broadcast system.
This is a configuration for setting the device .

As a result, the broadcast system control circuit once restarts.
If the cassette has been used,
When playing back a cassette without detaching the cassette, it is possible to immediately set the broadcasting system of the magnetic tape without discriminating the broadcasting system with the discrimination result storage setting means, so that the operation of discriminating the broadcasting system is unnecessary. At the same time, the time required for switching the broadcasting system is not required, and the time required for starting the reproduction of the color television signal can be shortened.

[Brief description of the drawings]

FIG. 1 is a flowchart of a mode determination routine.

FIG. 2 is a block diagram of a broadcast system control circuit.

FIG. 3 is a flowchart of a conventional mode determination routine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal input circuit 2 PAL / NTSC discrimination circuit 3 Servo control circuit (discrimination result storage setting means) 4 Magnetic tape 5 Magnetic head 6 Capstan FG head 7 Amplifier circuit 8 Amplifier circuit 9 Capstan motor 10 Count register circuit 11 PAL / Comparison circuit for NTSC discrimination 12 Mode discrimination circuit 13 Register circuit for servo control 14 Servo circuit

Claims (1)

(57) [Claims] 1. A magnetic recording / reproducing apparatus capable of recording and reproducing a plurality of color television signals of different broadcasting systems,
In a broadcast system control circuit having a determination circuit for determining a broadcast system of a color television signal recorded on a magnetic tape of an inserted cassette, the cassette is provided with a magnetic recording / reproducing device.
After being inserted into the
A determination result storage means for storing a broadcast system;
The determination result storage setting means further includes a magnetic recording
If the playback operation is performed before the recording / playback device is
In the case of magnetic recording,
A broadcast system control circuit for setting a playback device .