GB2331903A - Circuit for automatically adjusting the phase and amplitude of the horizontal deflection current in a multi-sync monitor - Google Patents
Circuit for automatically adjusting the phase and amplitude of the horizontal deflection current in a multi-sync monitor Download PDFInfo
- Publication number
- GB2331903A GB2331903A GB9818635A GB9818635A GB2331903A GB 2331903 A GB2331903 A GB 2331903A GB 9818635 A GB9818635 A GB 9818635A GB 9818635 A GB9818635 A GB 9818635A GB 2331903 A GB2331903 A GB 2331903A
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- GB
- United Kingdom
- Prior art keywords
- phase
- horizontal deflection
- amplitude
- adjusting
- deflection current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
- H04N3/27—Circuits special to multi-standard receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
- H04N3/22—Circuits for controlling dimensions, shape or centering of picture on screen
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Details Of Television Scanning (AREA)
Abstract
A circuit for automatically adjusting both the phase and amplitude of the horizontal deflection current depending on video modes comprises a sensing unit 11 (dummy transformer T21, fig 2) for sensing a deflection current flowing through a horizontal deflection coil H.DY. In the controller 16 a phase adjusting unit adjusts the phase of the horizontal deflection current according to a phase correcting signal determined by the difference between a positive and a negative rectified value of the sensed current (D22, D21, fig 2) and an amplitude adjusting unit adjusts the amplitude of horizontal deflection current according to a size correcting signal determined by the difference between a rectified value of the sensed current (D41, D42, fig 4) and a reference DC level. Accordingly, the phase and amplitude of horizontal deflection current can be automatically adjusted regardless of the video modes.
Description
1 2331903 CIRCUIT FOR ADJUSTING PHASE AND AMPLITUDE OF HORIZONTAL
DEFELCTION CURRENT AUTOMATICALLY IN MULTISYNC MONITOR The present invention relates to a horizontal deflection circuit in a multisync monitor, and more particularly to a circuit for adjusting the phase and amplitude of horizontal deflection current automatically according to video modes.
In a multisync monitor, circuit constants are automatically adjusted according to video modes, and then picture is reproduced on the screen. In general, the video modes are distinguished by the frequency of horizontal and vertical sync signals, and determined by the types of video cards, for example, EGA, VGA, SVGA and XGA, inserted in a host computer. As the video mode is changed, the circuit constants are changed under the control of the microcomputer in the multisync monitor.
In particular, both phase control data for adjusting the phase of horizontal deflection current varied by the video modes and size control data for adjusting the horizontal screen size are stored in the microcomputer. In mass production, these phase and size control data are stored in the microcomputer for each of video modes.
However, even though the phase and amplitude of horizontal deflection current can be adjusted according to the video modes by using the phase and size control data in the microcomputer, there is a limitation in storing the phase and size control data for every types of video modes. So, for the video mode in which the phase and size control data aren't stored in the microcomputer, a user has to operate switches to adjust the horizontal phase and screen size. Also much time is required for storing the phase and size control data in the microcomputer for every types of video modes in mass production.
1 In view of the foregoing, it is an object of the present invention to provide a C, circuit for adjusting the phase and amplitude of horizontal deflection current automatically according to video modes by using horizontal phase and size information detected from a dummy transformer connected between a horizontal deflection coil and a deflection current generator, in a multisync monitor.
According to the present invention there is provided a circuit for adjusting phase and amplitude of horizontal deflection current automatically depending on video modes in a mutisync monitor, characternized by comprising: sensing means for sensing deflection current flowing through a horizontal deflection coil and generating the sensed current; phase adjusting means for adjusting the phase of horizontal deflection current according to a phase correcting signal determined by the difference between a :D Zn I positive and a negative rectified values of the sensed current; and amplitude adjusting means for adjusting the amplitude of horizontal deflection current according to a size correcting signal determined by the difference between a rectified value of the sensed current and a reference DC level.
The above and other ob ects, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:
Fig. I is a schematic block diagram of a circuit for adjusting the phase and amplitude of horizontal deflection current automatically for the video modes accordinLy to the present invention, - I = Fi, 2 is a detailed block diagram of a circuit for adjusting the phase of horizontal I I deflection current automatically for the video modes according to an embodiment of the present invention, 2 Figs. 3A to 3E are waveforms showing the respective signals in Fig. 2, Fig. 4 is a detailed block diagram of a circuit for adjusting the amplitude of horizontal deflection current automatically for the video modes according to an embodiment of the present invention, and Figs. 5A to 5C are waveforms showing the respective signals in Fig. 4.
Referring to the accompanying drawings, detailed description of the preferred embodiment will be given. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Referring to Fig. 1, an automatic adjustment circuit for the phase and amplitude of horizontal deflection current according to the present invention comprises a horizontal deflection coil H.DY, a sensing unit 11, a rectifying unit 12, a first converting unit 15, a controller 16, a second converting unit 17, and an adjusting unit 18. The rectifying unit 12 comprises a half-wave rectifying part 13 having a first rectifier 131 and a comparator 132 and a second rectifier 14 as a full-wave rectifying part.
The sensing unit 11 senses a deflection current flowing through the horizontal deflection coil H.DY and provides the sensed current to the half-wave rectifying part 13 of the rectifying unit 12. The sensing unit 11 can be implemented by a dununy transformer as shown in the following Figs. 2 and 4. In the half-wave rectifying part 13, the first rectifier 131 performs positive and negative half-wave rectifying of the sensed current from the sensing unit 11. The comparator 132 compares DC level of positive and negative half-wave rectified values from the first rectifier 131 and generates a first analog, signal corresponding to the difference between the two DC levels. The second rectifier 14 performs full-wave rectifying of the sensed current from the sensing unit 11 and generates a second analog signal corresponding to full-wave rectified value. The first converting 3 unit 15 converts the first analog signal from the comparator 132 and the second analog signal from the second rectifier 14 into a first and a second digital signals, respectively.
The controller 16 generates horizontal phase and size correcting signals by using the first and the second digital signals, respectively. The second converting unit 17 converts the horizontal phase and size correcting signals from the controller 16 into a third and a fourth analog signals, respectively. The adjusting unit 18 adjusts the phase and amplitude of horizontal deflection current according to the third and the fourth analog signals, respectively.
Fig. 2 shows a detailed block diagram of a circuit for adjusting the phase of horizontal deflection current automatically for the video modes according to a preferred embodiment of the present invention.
The automatic adjustment circuit for the horizontal phase comprises a horizontal deflection coil H.DY, a dummy transformer T21 as a sensing unit, a deflection current generator 20, a half-wave rectifying unit 21 having a rectifier 22 and a comparator 24, an analog/digital converter 26, a controller 28, and a digital/analog converter 30. The rectifier 22 comprises a first and a second diodes D21 and D22, a first to a fourth capacitors C21 to C24 and a first and a second resisters R21 and R.22.
The deflection current generator 20 generates a horizontal deflection current and provides it to the horizontal deflection coil H.DY. The primary winding of the dummy transformer T21 is connected between the horizontal deflection coil H.DY and the deflection current generator 20. The dummy transformer T21 senses the deflection current in its secondary winding and provides the sensed current to the rectifier 22 of the half-wave rectifying unit 21.
4 In the rectifier 22, the first and the second diodes D21 and D22 perform positive and negative half-wave rectifying of the sensed current from the dummy transformer T21, respectively. The first and the second capacitors C21 and C22 perform smoothing and filtering of the positive half-wave rectified value from the first diode D21 respectively, and the third and the fourth capacitors C23 and C24 perforTn smoothing and filtering of the negative half-wave rectified value from the second diode D22 respectively. The two filtered values are applied to the comparator 24 via the first and the second resistors R21 and R22, respectively. The comparator 24 compares DC level of the two filtered values from the rectifier 22 and generates a first analog signal corresponding to the difference between the DC level of the two filtered values to be provided to the analog/digital converter 26.
The analog/digital converter 26 converts the first analog signal from the comparator 24 into a digital signal. The controller 28 generates a horizontal phase correcting signal for making the first analog signal zero by using the digital signal from the analog/digital converter 26. The digital/analog converter 30 converts the horizontal phase correcting signal from the controller 28 into a second analog signal to be provided to the deflection current generator 20.
Next, the operation of the automatic adjustment circuit for the horizontal phase will be described in detail, in conjunction with Figs. 3A to 3E.
When the deflection current flowing through the horizontal deflection coil H.DY has a normal phase in a video mode, the sensed current induced in the secondary winding of the dummy transformer T21 can be represented as shown in (a) of Fig. 3A. In (a) of Fig. 3A, the amplitude of the sensed current becomes smaller than that of the deflection current flowing through the horizontal deflection coil H.DY, and the amplitude of the 1 positive and the negative components are the same each other. In case of the sensed current above, the positive and the negative half-rectified values from the rectifier 22 have constant positive and negative DC levels V1 and -V1 as shown in Figs. 3B and 3C, respectively, and the two DC levels V1 and -V1 are applied to the comparator 24. The comparator 24 compares the absolute value of the two DC levels V1 and -V1 and generates the first analog signal indicating that the difference between the two absolte values is zero so as to be provided to the controller 28 as the digital signal via the analog/digital converter 26. At this time, the controller 28 doesn't generate the horizontal phase correcting signal since the first analog signal becomes zero by the normal phase of the horizontal deflection current.
Meanwhile, when the deflection current flowing through the horizontal deflection coil H.DY has an abnormal phase in a video mode, the sensed current induced in the secondary winding of the dummy transformer T21 can be represented as shown in (b) of Fig. 3A. In (b) of Fig. 3A, the amplitude of the sensed current becomes smaller than that of the deflection current flowing through the horizontal deflection coil H.DY, and its positive amplitude is larger than its negative amplitude. In case of the sensed current above, the positive and the negative half-wave rectified values from the rectifier 22 have constant DC levels V2 and -V3 as shown in Figs. 3D and 3E respectively, and the two DC levels V2 and -V3 are applied to the comparator 24. The comparator 24 compares the absolute value of the two DC levels V2 and -V3 and generates the first analog signal corresponding to the difference between the two absolte values so as to be provided to the controller 28 as the digital signal via the analog/digital converter 26. The controller 28 generates the horizontal phase correcting signal depending on the digital signal from the analog/digital converter 26 and provides it to the deflection current generator 20 as the 6 second analog signal via the digital/analog converter 30. Then, the deflection current generator 20 adjusts the phase of the horizontal deflection current by the second analog signal so that the absolute value of the two DC levels can be the same, which makes the first analog signal zero.
Fig. 4 shows a detailed block diagram of a circuit for adjusting the amplitude of horizontal deflection current automatically for the video modes according to a preferred embodiment of the present invention.
The automatic adjustment circuit for the horizontal amplitude comprises a horizontal deflection coil H.DY, a dummy transformer T41 as a sensing unit, a deflection current generator 40, a full-wave rectifying unit 42, an analog/digital converter 44, a controller 46, a digital/analog converter 48, a size adjusting unit 50, and a PNP transistor Q41. The full-wave rectifying unit 42 comprises a third and a fourth diodes D41 and D42, a fifth and a sixth capacitors C41 and C42 and a third resister R41.
Since operations for the deflection current generator 40 and the dummy transformer T41 are the same as those in Fig. 2, those will be omitted in the following description.
In the full-wave rectifying unit 42, the third arid the fourth diodes D41 and D42 perform full-wave rectifying of the sensed current from the dummy transformer T41. The fifth and the sixth capacitors C41 and C42 perform smoothing and filtering of the full wave rectified value from the third and the fourth diodes D41 and D42 and the filtered value is applied to the analo digital converter 44 as a first analog signal via the third 9/ It> resistor R41. The analog/digital converter 44 converts the first analog signal from the full-wave rectifying unit 42 into a digital signal.
7 The controller 46 compares the digital signal from the analog/digital converter 44 with a reference DC level and generates a horizontal size correcting signal. The digital/analog converter 48 converts the horizontal size correcting signal into a second analog signal and provides it to the size adjusting unit 50 which adjusts the amplitude of the horizontal deflection current.
Next, the operation of the automatic adjustment circuit for the horizontal amplitude will be described in detail, in conjunction with Figs. 5A to 5C.
When the deflection current flows through the horizontal deflection coil H.DY, the sensed current induced in the secondary winding of the dununy transformer T41 can be represented as shown in Fig. 5A. In Fig. 5A, the amplitude of the sensed current becomes smaller than that of the deflection current flowing through the horizontal deflection coil H.DY. The full-wave rectified value from the full-wave rectifying unit 42 has constant DC level as shown in Fig.5B and is applied to the controller 46 as the digital signal via the analog/digital converter 44.
The controller 46 stores the reference DC level for maintaining the horizontal screen size to a reference size regardless of the video modes therein and compares the digital signal with the reference DC level to generate the horizontal size correcting signal.
That is, when the digital signal becomes larger than the reference DC level as shown in (a) of Fig. 5C, the controller 46 generates the horizontal size correcting signal to compensate the difference dl between the two values. The horizontal size correcting signal is applied to the size adjusting unit 50 as the second analog signal via the digital/analog converter 48.
The size adjusting unit 50 generates a pulse signal having a duty ratio varied by the second analog signal to increase the turn-on period of the transistor Q41 and provides it to the base terminal of the transistor Q41. As a result, the current bypassed from the horizontal 8 deflection coil EDY to the transistor Q41 is increased and the horizontal screen size is decreased until it becomes the reference size.
Meanwhile, when the digital signal becomes smaller than the reference DC level as shown in (b) of Fie. 5C, the controller 46 generates the horlizontal size correctina slanal to compensate the difference C between the two values. The horizontal size correcting signal is applied to the size adjusting unit 50 as the second analog signal via the gital./analog converter 48. The size adjusting unit 50 generates a pulse signal having a dig duty ratio varied by the second analog signal to decrease the turn-on period of the transistor Q41 and provides it to the base terminal of the transistor Q41. As a result, the current bypassed from the horizontal deflection coil H.DY to the transistor Q41 is decreased and the horizontal screen size is increased until it becomes the reference size.
As described above, according to the present invention, the phase and the amplitude of horizontal deflection current can be adjusted automatically regardless of the video modes, by using horizontal phase and size information detected from a dummy transformer connected between a horizontal deflection coil and a deflection current generator. Therefore, there is no need for user to adjust the phase and the size of the horizontal screen manually according to the video modes.
While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
9
Claims (7)
1. A circuit for adjusting phase and amplitude of horizontal deflection current automatically depending on video modes in a mutisync monitor, characterized by comprising:
sensing means for sensing a deflection cur-rent flowing through a horizontal deflection coil and generating the sensed current; phase adjusting means for adjusting the phase of horizontal deflection current according to a phase correcting signal determined by the difference between a positive and a negative rectified values of the sensed current; and amplitude adjusting means for adjusting the amplitude of horizontal deflection current according to a size correcting signal determined by the difference between a rectified value of the sensed current and a reference DC level.
2. The circuit of claim 1, characterized in that said sensing means is implemented by a dummy transformer.
3. The circuit of claim 1, characterized in that said phase adjusting means comprises:
a rectifying unit for performing positive and negative half-wave rectifying of the sensed current from said sensing means; a comparator for comparing DC level of the positive and negative half- wave g unit and generating a first analog signal corresponding rectified values from said rectifyin., to the difference between the DC levels; a first converting unit for converting the first analog signal from said comparator into a digital signal; a controller for generating the phase correcting signal to make the first analog signal zero by using the digital signal; and a second converting unit for converting the phase correcting signal from said controller into a second analog signal and providing the second analog signal to a horizontal deflection current generator so as to adjust the phase of horizontal deflection current.
4. The circuit of claim 3, characterized in that said sensing means is implemented by a dummy transformer.
5. The circuit of claim 1, characterized in that said amplitude adjusting means comprises: a rectifying unit for performing full-wave rectifying of the sensed current from said sensing means and generating a first analog signal corresponding to the full-wave rectified value; a first converting unit for converting the first analog signal from said rectifying unit into a digital signal; a controller for comparing the digital signal from said first converting unit with the reference DC level and generating the size correcting signal; a second converting unit for converting the size correcting signal from said controller into a second analog signal; 11 a size adjusting unit for generating a pulse signal having a duty ratio varied by the second analog signal from said second converting unit; and a switching unit for adjusting the amplitude of horizontal deflection current by bypassing the horizontal deflection current during a turri-on period determined by the pulse signal from said size adjusting unit.
6. The circuit of claim 5, characterized in that said sensing means is implemented by a dummy transformer.
7. A circuit for adjusting phase and amplitude of horizontal deflection current automatically depending on video modes in a mutisync monitor constructed and arranged substantially as herein described with reference to or as shown in the accompanying drawings.
12
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019970064430A KR19990043428A (en) | 1997-11-29 | 1997-11-29 | Horizontal size automatic adjustment circuit of multi mode monitor |
| KR1019970064426A KR19990043425A (en) | 1997-11-29 | 1997-11-29 | Horizontal phase automatic adjustment circuit of multi-mode monitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9818635D0 GB9818635D0 (en) | 1998-10-21 |
| GB2331903A true GB2331903A (en) | 1999-06-02 |
Family
ID=26633210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9818635A Withdrawn GB2331903A (en) | 1997-11-29 | 1998-08-26 | Circuit for automatically adjusting the phase and amplitude of the horizontal deflection current in a multi-sync monitor |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2331903A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4414494A (en) * | 1981-04-06 | 1983-11-08 | Electrohome Limited | Regulation of the scan width of a raster scanned CRT deflection system |
| GB2230681A (en) * | 1989-04-15 | 1990-10-24 | Ibm | Automatic picture height and centering for differing display formats |
| GB2269080A (en) * | 1992-07-25 | 1994-01-26 | Ibm | Constant picture size for crt displays despite scan frequency changes |
-
1998
- 1998-08-26 GB GB9818635A patent/GB2331903A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4414494A (en) * | 1981-04-06 | 1983-11-08 | Electrohome Limited | Regulation of the scan width of a raster scanned CRT deflection system |
| GB2230681A (en) * | 1989-04-15 | 1990-10-24 | Ibm | Automatic picture height and centering for differing display formats |
| GB2269080A (en) * | 1992-07-25 | 1994-01-26 | Ibm | Constant picture size for crt displays despite scan frequency changes |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9818635D0 (en) | 1998-10-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |