JP2003333364A - Vertical synchronization stabilizing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical synchronization stabilizing apparatus for performing synchronization operations by using a vertical synchronization signal capable of providing a stable vertical synchronization signal even when the apparatus receives an input signal of a standard system, or a non-standard system or in a strong electric field or in a weak electric field. <P>SOLUTION: A microcomputer 8 allows a synchronization signal changeover switch 10 to be thrown to a position of receiving an external vertical synchronization signal 9 when the apparatus receives an input signal of the standard system in the strong electric field state. When an electric field level detected by the electric field level detection circuit 7 is close to a level of a weak electric field, the microcomputer 8 allows the synchronization signal changeover switch 10 to be thrown to a position connected to an automatic controller 11, also periodically selects the position of the external vertical synchronization signal 9 from the position of the automatic controller 11 at a prescribed interval as its control, and fixes the automatic control when the electric field strength reaches a weak electric field strength. The apparatus conducts similar control for a non-standard input signal. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical synchronization stabilizing device capable of obtaining a stable vertical synchronization signal with respect to an input signal in any state in a device which performs a synchronization operation using a vertical synchronization signal. It is a thing.

[0002]

2. Description of the Related Art As a vertical synchronizing device for the same purpose, there is a vertical synchronizing device described in Japanese Patent Laid-Open No. 02-148975.

FIG. 4 shows a conventional vertical synchronizing device. In FIG. 4, the sync separating device 12 functions to generate a video vertical synchronizing signal 14 (hereinafter referred to as an external vertical synchronizing signal) from an input video signal 13. By doing so, the internal vertical synchronization signal generator 15 generates an output pulse of the variable counter and synchronizes it when switching to the external vertical synchronization signal 14,
The vertical sync signal synchronized with the external vertical sync signal 14 is output. The automatic control device 16 detects the vertical sync distortion level of the input signal and automatically switches to the external vertical sync signal 14 when the distortion is large and to the internal vertical sync signal 15 when the distortion is small. The purpose is to obtain a stable vertical synchronizing signal by performing the above, and the synchronizing separator 12 and the internal vertical synchronizing signal generator 15 are provided.
And an automatic control device 16 and a changeover switch 17. As described above, in the conventional vertical synchronizing apparatus, when the input signal is the standard signal, the synchronizing processing is performed by the external vertical synchronizing signal, and when the input signal is a no signal input or the video vertical synchronizing signal having a cycle outside the predetermined range is received, the internal synchronizing signal is internally generated. Synchronization processing was performed by an automatic control device that switches to a vertical synchronization signal.

However, in the automatic control device 16, the internal vertical synchronizing signal is locked at a non-standard frequency when the synchronization changes only for a very short period of time such as when switching between local stations on the broadcasting station side. However, since the automatic control device 16 performs the processing with the non-standard internal vertical synchronizing signal as it is, there is a problem that the screen shakes vertically or the synchronization becomes unstable when the electric field is weak.

[0005]

In the conventional vertical synchronizing apparatus, when the input signal is the standard signal, the synchronizing process is performed by the external vertical synchronizing signal, and the vertical synchronizing signal of no signal is input or the video vertical synchronizing signal having a cycle outside the predetermined range is performed. When received, the synchronization process was performed by the automatic control device that switches to the internal vertical synchronization signal, but when the vertical frequency changes only for a very short period, such as when switching between local stations on the broadcasting station side, With the automatic control device alone, when switching between local stations occurs and the vertical frequency changes outside the control range, control is performed to switch to the internal vertical synchronization signal once, but the time when the vertical frequency shifts is very short. The vertical sync signal is locked at a non-standard frequency, and the locked frequency is non-standard, so the automatic controller does not switch to the external vertical sync signal. To operate in a non-standard internal vertical synchronizing signal, the screen phenomenon vertical synchronizing or swinging vertically unstable there is a problem that occurs.

According to the present invention, even when the automatic control device is operating with the internal vertical synchronizing signal, the microcomputer periodically switches to the external vertical synchronizing signal to correct the phase of the internal vertical synchronizing signal and stabilize the vertical synchronizing signal. You get the signal.

[0007]

In order to solve the above-mentioned problems, according to the present invention, when an input signal is standard, a synchronizing process is performed by an external vertical synchronizing signal without using an automatic control device,
It has a device that switches to an automatic control device when a non-standard signal and a weak electric field signal are input, and even if the internal vertical synchronization signal is locked at a non-standard frequency during synchronization processing by the automatic control device, it is regularly scheduled by the microcomputer. By forcibly switching to the external vertical sync signal, the phase of the internal vertical sync signal is corrected and the internal vertical sync signal synchronized with the external vertical sync signal is obtained, so stable synchronization processing can be performed. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a device for performing a synchronous operation using a vertical synchronizing signal, in which an operation of switching the vertical synchronizing signal with respect to an input signal in a standard state and a non-standard state is performed. It is characterized by performing
It has an effect of obtaining a stable vertical synchronizing signal even in a non-standard signal state.

According to a second aspect of the present invention, in an apparatus for performing a synchronizing operation using a vertical synchronizing signal, an apparatus for discriminating between a standard and a non-standard of an input signal, an external vertical synchronizing signal and an internal vertical synchronizing signal. It is characterized by having an automatic control device that automatically switches the input and output according to the deviation of the vertical frequency, and a means for fixing the external vertical synchronizing signal to the external vertical synchronizing signal. It has the function of making it possible to obtain a stable vertical synchronization signal.

According to a third aspect of the present invention, in a device that performs a synchronizing operation using a vertical synchronizing signal, a switching operation of the vertical synchronizing signal is performed for an input signal in a strong electric field state and a weak electric field state. This has the effect of making it possible to obtain a stable vertical synchronizing signal even in a weak electric field state.

According to a fourth aspect of the present invention, in a device that performs a synchronous operation using a vertical synchronizing signal, a device that detects an electric field level of an input signal, an external vertical synchronizing signal and an internal vertical synchronizing signal are vertically arranged. It is characterized by having an automatic control device that automatically switches depending on the frequency shift and a means for fixing to the external vertical synchronizing signal, so that it is always synchronized with the external vertical synchronizing signal even for input signals in the weak electric field state. It has the function of making it possible to obtain a stable vertical synchronizing signal.

According to a fifth aspect of the present invention, in an apparatus for performing a synchronous operation using a vertical synchronizing signal, an automatic control apparatus is provided for an input signal in a state near a standard / non-standard and a strong electric field / weak electric field discrimination boundary. It is characterized by periodically forcibly switching to the vertical synchronization signal while performing processing at
It has an effect of obtaining a stable vertical synchronizing signal even for an input signal in a state near the discrimination boundary.

According to a sixth aspect of the present invention, in a device that performs a synchronous operation using a vertical synchronization signal, a device that detects an electric field level of an input signal and a standard or non-standard of the input signal is discriminated. A device, an automatic control device for automatically switching between an external vertical synchronizing signal and an internal vertical synchronizing signal depending on a vertical frequency shift, and means for fixing the external vertical synchronizing signal to the external vertical synchronizing signal,
It is characterized by having a hysteresis area in the switching operation between the automatic control device and the fixed external vertical sync signal, and the external vertical sync signal is also used for the weak electric field state, the non-standard state and the input signal near the discrimination boundary. It has the function of making it possible to obtain a synchronized internal vertical synchronizing signal.

Embodiments of the present invention will be described below with reference to FIGS. 1, 2 and 3.

(Embodiment 1) FIG. 1 shows the second aspect of the present invention.
FIG. 1 shows a vertical synchronization stabilizer, in which the electric field level detection circuit 1 integrates the noise amount of the input signal to quantify the noise level and informs the microcomputer 2 of the strong electric field and the weak electric field state. The microcomputer 2 controls the vertical synchronization changeover switch 4 so as to perform the synchronous operation by the external vertical synchronization signal 3 in the strong electric field state, and the electric field level detection circuit 1 causes the microcomputer 2 to operate the weak electric field. If it is determined that the automatic control device 5 is to be operated.

(Embodiment 2) FIG. 2 shows claim 4 of the present invention.
2 shows a vertical synchronization stabilizer according to FIG. 2, in which the standard / non-standard detection circuit 6 detects vertical and horizontal frequencies and distortion between frames from the input signal, and transmits the result to the microcomputer 8 so that the standard and non-standard states are achieved. The electric field level detection circuit 7 digitizes the noise amount of the input signal and transmits it to the microcomputer 8 to enable the judgment of the strong electric field and the weak electric field state. It acts. When the input video signal is a standard signal and has a strong electric field, the microcomputer 8 controls to fix the external vertical synchronizing signal 9 to perform the synchronizing operation, and the microcomputer 14 controls the standard / non-standard detecting circuit 6 to perform the synchronizing operation. If it is judged as non-standard,
Alternatively, when the electric field level detection circuit 7 determines that the electric field is weak, the synchronization signal changeover switch 10 is set to the automatic control device 1.
Performs the action of switching to 1.

(Embodiment 3) FIG. 2 shows claim 6 of the present invention.
2 shows a vertical synchronization stabilizer according to FIG. 2, in which the standard / non-standard detection circuit 6 detects vertical and horizontal frequencies and distortion between frames from the input signal, and transmits the result to the microcomputer 8 so that the standard and non-standard states are achieved. The electric field level detection circuit 7 digitizes the noise amount of the input signal and transmits it to the microcomputer 8 to enable the judgment of the strong electric field and the weak electric field state. It acts. When the input video signal is a standard signal and has a strong electric field, the microcomputer 8 controls to fix the external vertical sync signal 9 to perform the synchronous operation, and the microcomputer 8 controls the standard / non-standard detection circuit 6 When it is judged that it is non-standard or when the electric field level detection circuit 7 judges that it is a weak electric field, the synchronization signal changeover switch 10 is set to the automatic controller 11.
To switch to.

Further, the microcomputer 8 provides a hysteresis area near the boundary for judging the standard electric field, the non-standard electric field and the strong electric field and the weak electric field. In the hysteresis area, the microcomputer 8 switches the synchronization changeover switch 10 to the automatic control device 11 and periodically. This serves to switch the synchronization changeover switch 10 to the external vertical synchronization signal 9.

FIG. 3 shows an example of operation classification of the vertical synchronization stabilizer according to claim 6 of the present invention. In FIG. 3, the external vertical synchronization region 18 shows a state in which the input signal is standard and a strong electric field. In the external vertical synchronizing area 18, the microcomputer 8 of FIG. 2 fixes the synchronizing signal changeover switch 10 to the external vertical synchronizing signal 9 to perform the synchronizing process. In FIG. 3, the hysteresis region 19 has an input signal whose electric field level detection circuit 7 shown in FIG.
(Or the standard / non-standard detection circuit 6) indicates that the microcomputer 8 is near the boundary where the strong electric field and the weak electric field (or standard and non-standard) are judged, and the microcomputer 8 shown in FIG. Alternatively, the range to be the hysteresis region 19 is set for the numerical value transmitted from the standard / non-standard detection circuit 6). Hysteresis area 1 where the input signal is set
When it becomes 9, the microcomputer 8 switches the vertical synchronization changeover switch 10 to the automatic control unit 11, and the microcomputer 8 forcibly switches to the external vertical synchronization signal 9 at a fixed interval and at a fixed time interval. Align the phase of with the external vertical sync signal. When the weak electric field state (or non-standard state) becomes further than the hysteresis region 19, the automatic control region 20 is set, and the microcomputer 8 of FIG. 2 switches the synchronization signal changeover switch 10 to the automatic control device 11.

[0020]

As described above, according to the vertical synchronization stabilizer of the present invention, not only the standard signal but also the non-standard signal and the signal in the weak electric field state are stabilized by the internal vertical synchronization signal synchronized with the external vertical synchronization signal. It is possible to obtain a synchronization signal, and it is possible to perform a synchronization operation without disturbing vertical synchronization even when the frequency changes in a short period, such as when switching between local stations on the broadcasting station side.

[Brief description of drawings]

FIG. 1 is a block diagram of a vertical synchronization stabilizer according to claim 2 of the present invention.

FIG. 2 is a block diagram of a vertical synchronization stabilizer according to claims 4 and 6 of the present invention.

FIG. 3 is a diagram of an example of operation classification according to claim 6 of the present invention.

FIG. 4 is a block diagram of a conventional vertical synchronizing device.

[Explanation of symbols]

1 Electric field level detection circuit 2 microcomputer 3 External vertical sync signal 4 Vertical synchronization switch 5 Automatic control device 6 standard / non-standard detection circuit 7 Electric field level detection circuit 8 microcomputer 9 External vertical sync signal 10 Vertical sync switch 11 Automatic control device 12 Synchronous separation device 13 Input signal 14 External vertical sync signal 15 Internal vertical signal generator 16 Automatic control device 17 Vertical sync switch 18 External vertical sync area 19 Hysteresis area 20 Automatic control area

Claims (6)

[Claims] 1. A vertical synchronization stabilizing device, wherein in a device for performing a synchronization operation using a vertical synchronization signal, a vertical synchronization signal switching operation is performed for an input signal in a standard state and a non-standard state. 2. A device for performing a synchronizing operation using a vertical synchronizing signal, wherein a device for discriminating between a standard and a non-standard of an input signal, an external vertical synchronizing signal and an internal vertical synchronizing signal synchronized with the external vertical synchronizing signal Vertical sync that makes it possible to obtain an internal vertical sync signal that is synchronized with the external vertical sync signal even for an input signal in a non-standard state by having a device that automatically switches according to the shift and a means for switching to the external vertical sync signal Signal stabilizer. 3. An apparatus for performing a synchronizing operation using a vertical synchronizing signal, wherein a vertical synchronizing signal switching operation is performed with respect to an input signal in a strong electric field state and a weak electric field state. 4. A device for performing a synchronizing operation using a vertical synchronizing signal, wherein a device for detecting an electric field level of an input signal, an external vertical synchronizing signal and an internal vertical synchronizing signal synchronized with the external vertical synchronizing signal are automatically adjusted by a vertical frequency shift. By having a device for dynamically switching and a means for switching to an external vertical synchronizing signal,
A vertical synchronizing signal stabilizer capable of obtaining an internal vertical synchronizing signal synchronized with an external vertical synchronizing signal even for an input signal in a weak electric field state. 5. An apparatus for performing a synchronizing operation using a vertical synchronizing signal, wherein a switching operation of the vertical synchronizing signal is performed with respect to an input signal in a state near a boundary between a standard electric field and a non-standard electric field and a strong electric field and a weak electric field. Characteristic vertical synchronization stabilizer. 6. A device for performing a synchronizing operation using a vertical synchronizing signal, a device for detecting an electric field level of an input signal, a device for discriminating between a standard and a non-standard of the input signal, and an external vertical synchronization. By automatically switching the signal and the internal vertical synchronizing signal synchronized with it by means of the deviation of the vertical frequency and the means for switching to the external vertical synchronizing signal, and by having a hysteresis area in the switching operation between the automatic control device and the external vertical synchronizing signal, A vertical synchronizing signal stabilizing device capable of obtaining an internal vertical synchronizing signal synchronized with an external vertical synchronizing signal even for a weak electric field state, a non-standard state, and an input signal near its discrimination boundary.