CA2042480C - Horizontal deflection circuit - Google Patents
Horizontal deflection circuitInfo
- Publication number
- CA2042480C CA2042480C CA 2042480 CA2042480A CA2042480C CA 2042480 C CA2042480 C CA 2042480C CA 2042480 CA2042480 CA 2042480 CA 2042480 A CA2042480 A CA 2042480A CA 2042480 C CA2042480 C CA 2042480C
- Authority
- CA
- Canada
- Prior art keywords
- horizontal
- circuit
- voltage
- output
- horizontal deflection
- 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.)
- Expired - Fee Related
Links
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
- H04N3/22—Circuits for controlling dimensions, shape or centering of picture on screen
- H04N3/23—Distortion correction, e.g. for pincushion distortion correction, S-correction
- H04N3/233—Distortion correction, e.g. for pincushion distortion correction, S-correction using active elements
-
- 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
- H04N3/23—Distortion correction, e.g. for pincushion distortion correction, S-correction
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Details Of Television Scanning (AREA)
Abstract
A horizontal deflection circuit for a cathode-ray tube video display terminal or a projection tube has a circuit for correcting pincushion or trapezoid distortion on the raster of the CRT. The correction circuit comprises a modulator for modulating a voltage to be supplied to a driving transformer whereto a horizontal oscillation signal is applied for driving a horizontal deflection output switching device in a horizontal deflection output circuit. The modulation is made in compliance with a component of a vertical synchronization alternating current of a voltage supplied to the horizontal deflection output circuit.
Description
TITLE OF THE lNV~h llON
Horizontal Deflection Circuit FIELD OF THE lNV~hllON AND RELATED ART STATEMENT
1. FIELD OF THE lNV~NllON
The present invention relates to a horizontal deflection circuit for correcting picture distortions in the raster of a cathode-ray tube.
Horizontal Deflection Circuit FIELD OF THE lNV~hllON AND RELATED ART STATEMENT
1. FIELD OF THE lNV~NllON
The present invention relates to a horizontal deflection circuit for correcting picture distortions in the raster of a cathode-ray tube.
2. BRIEF DESCRIPTION OF THE PRIOR ART
Direct-viewing cathode-ray tubes equipped with RGB input ter~inAl.s for use as video display te, inAl.s or projection-tubes for use in video projectors have recently become increasingly popular due to the popularity of computers. In such applications, where a wide angle of deflection and a flat display-face are sometimes indispensable, it is especially important that pincushion distortion or trapezoid distortion on the raster of the cathode-ray tube should be avoided as far as possible. Thus, there have been proposed a number of circuits for correcting such distortions, but these have enjoyed only limited success.
OBJECT AND SUMMARY OF THE lNV~..llON
The object of the present invention is to provide a horizontal deflection circuit capable of displaying the picture image signal at the center of the raster and removing distortions in the raster and the picture image.
In accordance with the present invention, there is provided a horizontal deflection circuit which comprises horizontal automatic frequency control means for outputting the horizontal oscillation signal whose frequency is controlled to a predetermined frequency, and modulation means for modulating a voltage to be supplied to the driving transformer, which is driven by the horizontal oscillation signal and drives a horizontal deflection output switching device in the horizontal deflection output circuit, in compliance with the vertical synchronization alternating current component of the voltage supplied to the horizontal deflection output circuit.
According to another aspect of the present invention there is provided a horizontal deflection circuit for use in a cathode-ray tube display terminal, which comprises; i) a delay circuit for delaying the horizontal ~' oscillation signal; ii) a horizontal automatic frequency control circuit which outputs a comparison output signal by comparing the phase of the delayed signal from the delay circuit with the phase of the horizontal synchronization signal, and causes the horizontal oscillation circuit to output the horizontal oscillation signal whose frequency is controlled at the horizontal synchronization signal frequency by the horizontal comparison output signal, and iii) a horizontal driving voltage modulation circuit interposed between an output end of a horizontal regulation transistor and a voltage supply terminal of the driving transformer, which is driven by the horizontal oscillation signal and drives the horizontal deflection output switching device in the horizontal deflection output circuit. The horizontal driving voltage modulation circuit comprises a) a potentiometer connected between an output end of the horizontal regulation transistor and reference ground potential, b) a voltage supply transistor for supplying the driving transformer with a voltage, c) a capacitor interposed between a variable terminal of the potentiometer and the base of the voltage supply transistor, d) base-bias setting means for setting a base-bias of the voltage supply transistor, and e) an integrating circuit interposed between the output end of the voltage supply transistor and the driving transformer.
By arranging the circuit in accordance with the invention, the voltage supplied to the driving transformer is modulated in compliance with the magnitude of the horizontal deflection current and in correspondence with the waveform of the alternating current component of the vertical deflection period, thus rendering the driving conditions of the horizontal output transistor independent of the vertical deflection period and hence removing the occurrencè of picture distortion.
In the circuitry of the present invention, the vertical lines in the picture will not be inclined or curved as in the case of conventional circuitry (as will be more fully described below), but will be maintained straight and vertical, even when a horizontal trapezoid correction or a horizontal pincushion correction is performed.
The invention will now be described further by way of example only and with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAUINGS
FIG. 1 is a circuit diagram showing a preferred embodiment of the horizontal deflection circuit in accordance with the present invention;
Direct-viewing cathode-ray tubes equipped with RGB input ter~inAl.s for use as video display te, inAl.s or projection-tubes for use in video projectors have recently become increasingly popular due to the popularity of computers. In such applications, where a wide angle of deflection and a flat display-face are sometimes indispensable, it is especially important that pincushion distortion or trapezoid distortion on the raster of the cathode-ray tube should be avoided as far as possible. Thus, there have been proposed a number of circuits for correcting such distortions, but these have enjoyed only limited success.
OBJECT AND SUMMARY OF THE lNV~..llON
The object of the present invention is to provide a horizontal deflection circuit capable of displaying the picture image signal at the center of the raster and removing distortions in the raster and the picture image.
In accordance with the present invention, there is provided a horizontal deflection circuit which comprises horizontal automatic frequency control means for outputting the horizontal oscillation signal whose frequency is controlled to a predetermined frequency, and modulation means for modulating a voltage to be supplied to the driving transformer, which is driven by the horizontal oscillation signal and drives a horizontal deflection output switching device in the horizontal deflection output circuit, in compliance with the vertical synchronization alternating current component of the voltage supplied to the horizontal deflection output circuit.
According to another aspect of the present invention there is provided a horizontal deflection circuit for use in a cathode-ray tube display terminal, which comprises; i) a delay circuit for delaying the horizontal ~' oscillation signal; ii) a horizontal automatic frequency control circuit which outputs a comparison output signal by comparing the phase of the delayed signal from the delay circuit with the phase of the horizontal synchronization signal, and causes the horizontal oscillation circuit to output the horizontal oscillation signal whose frequency is controlled at the horizontal synchronization signal frequency by the horizontal comparison output signal, and iii) a horizontal driving voltage modulation circuit interposed between an output end of a horizontal regulation transistor and a voltage supply terminal of the driving transformer, which is driven by the horizontal oscillation signal and drives the horizontal deflection output switching device in the horizontal deflection output circuit. The horizontal driving voltage modulation circuit comprises a) a potentiometer connected between an output end of the horizontal regulation transistor and reference ground potential, b) a voltage supply transistor for supplying the driving transformer with a voltage, c) a capacitor interposed between a variable terminal of the potentiometer and the base of the voltage supply transistor, d) base-bias setting means for setting a base-bias of the voltage supply transistor, and e) an integrating circuit interposed between the output end of the voltage supply transistor and the driving transformer.
By arranging the circuit in accordance with the invention, the voltage supplied to the driving transformer is modulated in compliance with the magnitude of the horizontal deflection current and in correspondence with the waveform of the alternating current component of the vertical deflection period, thus rendering the driving conditions of the horizontal output transistor independent of the vertical deflection period and hence removing the occurrencè of picture distortion.
In the circuitry of the present invention, the vertical lines in the picture will not be inclined or curved as in the case of conventional circuitry (as will be more fully described below), but will be maintained straight and vertical, even when a horizontal trapezoid correction or a horizontal pincushion correction is performed.
The invention will now be described further by way of example only and with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAUINGS
FIG. 1 is a circuit diagram showing a preferred embodiment of the horizontal deflection circuit in accordance with the present invention;
FIG. 2 is a circuit diagram showing one example of a conventional horizontal deflection circuit;
FIGS. 3(a) through 3(f) are waveform charts of signals present at various parts or points in the circuit diagrams of FIGS. 1 and 2, respectively;
FIG. 4 illustrates correction of horizontal trapezoid distortion;
FIG. 5 illustrates correction of pincushion distortion;
FIG. 6 is a waveform chart representing the collector current of the horizontal output transistor 7, when the horizontal trapezoid distortion is corrected; and FIG. 7 is a waveform chart representing the collector current of the horizontal output transistor 7, when horizontal pincushion distortion is corrected.
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.
D~TATT.~n DESCRIPTION OF THE PRIOR ART
FIG. 2 is a circuit diagram showing an example of a conventional horizontal deflection circuit. In the circuit shown in FIG. 2, a horizontal oscillator circuit 1 is connected to a delay circuit 2 and also, through a horizontal oscillation output amplifying circuit 3, to the base of a horizontal drive transistor 5. The collector of the horizontal drive transistor 5 is connected to one end of a primary winding of a horizontal drive transformer 4 and the emitter is grounded. The delay circuit 2 is also connected to a horizontal automatic frequency control circuit (hereinafter, called a horizontal AFC circuit) 6 whereto a horizontal synchronization signal c is inputted. The output terminal of the horizontal AFC circuit 6 is connected to the horizontal oscillator circuit 1.
In the horizontal AFC circuit 6, a known phase comparator contained therein compares the phase of a delay output signal b from the delay circuit 2 with the phase of the horizontal synchronization signal c and generates a comparison output "d", which controls the frequency of the horizontal oscillator circuit 1 to conform it to the frequency of the horizontal - 35 synchronization signal. The other end of the primary winding of the horizontal drive transformer 4 is connected to a voltage-supply terminal B
FIGS. 3(a) through 3(f) are waveform charts of signals present at various parts or points in the circuit diagrams of FIGS. 1 and 2, respectively;
FIG. 4 illustrates correction of horizontal trapezoid distortion;
FIG. 5 illustrates correction of pincushion distortion;
FIG. 6 is a waveform chart representing the collector current of the horizontal output transistor 7, when the horizontal trapezoid distortion is corrected; and FIG. 7 is a waveform chart representing the collector current of the horizontal output transistor 7, when horizontal pincushion distortion is corrected.
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.
D~TATT.~n DESCRIPTION OF THE PRIOR ART
FIG. 2 is a circuit diagram showing an example of a conventional horizontal deflection circuit. In the circuit shown in FIG. 2, a horizontal oscillator circuit 1 is connected to a delay circuit 2 and also, through a horizontal oscillation output amplifying circuit 3, to the base of a horizontal drive transistor 5. The collector of the horizontal drive transistor 5 is connected to one end of a primary winding of a horizontal drive transformer 4 and the emitter is grounded. The delay circuit 2 is also connected to a horizontal automatic frequency control circuit (hereinafter, called a horizontal AFC circuit) 6 whereto a horizontal synchronization signal c is inputted. The output terminal of the horizontal AFC circuit 6 is connected to the horizontal oscillator circuit 1.
In the horizontal AFC circuit 6, a known phase comparator contained therein compares the phase of a delay output signal b from the delay circuit 2 with the phase of the horizontal synchronization signal c and generates a comparison output "d", which controls the frequency of the horizontal oscillator circuit 1 to conform it to the frequency of the horizontal - 35 synchronization signal. The other end of the primary winding of the horizontal drive transformer 4 is connected to a voltage-supply terminal B
to which a stabilized voltage Bl for horizontal driving is applied. The above-mentioned components constitute a horizontal driving circuit.
On the other hand, one end of a secondary winding of the horizontal drive transformer 4 is connected to the base of a horizontal output transistor 7, which acts as a switching device. The collector of the output transistor 7 is connected to the emitter of a horizontal regulation transistor 9 through a horizontal choke coil 8, and also to a cathode of a horizontal damper diode 10, a horizontal resonance capacitor 11 and one end of a horizontal deflection coil 12. The emitter of the horizontal output transistor 7, the anode of the horizontal damper diode 10 and the other end of the horizontal resonance capacitor 11 are directly grounded in common, whereas the other end of the horizontal deflection coil 12 is grounded through a horizontal S-shape correcting capacitor 13. As described above, a horizontal deflection output circuit is configured by the horizontal output transistor 7, the horizontal choke coil 8, the horizontal ~Amper diode 10, the horizontal resonance capacitor 11, the horizontal deflection coil 12 and the horizontal S-shape correcting capacitor 13. Thus, the horizontal deflection circuit is composed of this horizontal deflection output circuit and the aforementioned horizontal driving circuit.
In the above-mentioned prior art circuit, the collector of the horizontal regulation transistor 9 is supplied with a horizontal deflection voltage B2.
A description of the operation and function of the above-mentioned horizontal deflection output circuit per se is omitted here, because they are well known and have no relationship to the operation of the raster distortion correcting function. Thus, only the operation and function of the raster distortion correction part of the horizontal deflection circuit will be explained in the following paragraphs.
The phase relationship between the horizontal synchronisation signal of a computer and the display signal image region varies with the computer.
Therefore, in order to center the displayed signal image on the raster, a measure as shown in FIG. 2 has conventionally been taken. Referring to the circuit of FIG. 2, a horizontal oscillation signal ~a" as shown by FIG. 3 (a) is supplied from the horizontal oscillator circuit 1 to the delay circuit 2. Then, the phases of an output signal "b" as shown by FIG. 3 (b) from the delay circuit 2 and a horizontal synchronization signal "c" as s shown by FIG. 3 (c) are compared with each other. Thereby, the horizontal AFC circuit 6 is made to adjust the delay time tl of the delay circuit 2 in the circuitry shown in FIG. 2. As described, the horizontal drive transformer 4 is supplied with a constant stabilized voltage Bl in this conventional circuitry. Thus, when a horizontal trapezoid correction as shown by FIG. 4 or a horizontal pincushion correction as shown by FIG. 5 is applied to the picture, the collector current i2 of the horizontal output transistor 7 varies with a vertical deflection period l/fv, as shown by FIGS. 6 and 7, respectively. In that situation, since the Ib end (i.e. the end value of the base current il over a predetermined time period) shown by FIG. 3 (d) is constant, the driving condition of the horizontal output transistor 7 is caused to vary with the vertical deflection period. In FIGS. 6 and 7. fH indicates the horizontal deflection frequency and fV
indicates the vertical deflection frequency.
In the previously described conventional circuit, an electric charge accumulating time t2 shown by FIG. 3 (e) of the horizontal output transistor 7 varies with the vertical deflection period, thereby varying the phase relationship between the horizontal synchronization signal c and a horizontal deflection output pulse e (which is the collector voltage of the horizontal output transistor 7), hence varying the vertical deflection period. Therefore, the circuit has a drawback that the displayed rasters are distorted as shown by the broken lines in FIGS. 4 and 5, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a circuit diagram showing a preferred embodiment of the horizontal deflection circuit in accordance with the present invention, wherein the same reference symbols and numerals as those used in the above discussion of the conventional circuit, are used for designating the same or similar components, and their descriptions are omitted here.
In FIG. 1, a horizontal driving voltage modulation circuit 21 is interposed between the voltage supply terminal of the primary winding of the horizontal drive transformer 4 and the emitter of the horizontal regulation transistor 9. More particularly, the emitter of the horizontal regulation transistor 9 is grounded through a variable resistor 22 whose variable terminal is connected to the base of the voltage supply transistor 24 and to resistors 25 and 26 at their connection point through a capacitor 2042~80 23 for transferring only the alternating current component. The collector of the voltage supply transistor 24 is connected to a collector voltage supply terminal B3 and is grounded through the resistors 25 and 26. The emitter of the voltage supply transistor 24 is connected to the voltage supply end of the primary coil of the horizontal drive transformer 4 through a resistor 27 and is grounded through a filter capacitor 28, and the emitter itself is grounded through a resistor 29.
By arranging the circuit as previously described, when a trapezoid correction is performed on the raster or picture as shown by FIG. 4, a signal of vertical saw-tooth waveform g appears as the emitter voltage of the horizontal regulation transistor 9. This waveform also appears as a vertical deflection period alternating current component of the emitter voltage at the voltage supply transistor 24, thus causing the voltage supplied to the horizontal driving transformer 4 to be modulated with the vertical saw-tooth wave signal g'.
Accordingly, the Ib end of the base current il of the horizontal output transistor 7 is caused to vary with the vertical deflection period, while the driving condition of the horizontal output transistor 7 is always kept constant instead of being varied with the vertical deflection period. As previously described, the electric charge accumulating time expressed as t2 in FIG. 3 (e) can also always be maintained constant, thus preventing inclination of the vertical line as indicated by the broken line in FIG. 4 and maintAining it both vertical and straight, even if the trapezoid correction is applied. It may safely be said that the same or similar advantages will also be obtained in the case of performing the pincushion correction.
In addition to the foregoing, the delay time tl of the delay circuit 2 is made adjustable from outside, thus rendering the width adjustment of the picture or raster possible by adjustment of the delay time tl.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
On the other hand, one end of a secondary winding of the horizontal drive transformer 4 is connected to the base of a horizontal output transistor 7, which acts as a switching device. The collector of the output transistor 7 is connected to the emitter of a horizontal regulation transistor 9 through a horizontal choke coil 8, and also to a cathode of a horizontal damper diode 10, a horizontal resonance capacitor 11 and one end of a horizontal deflection coil 12. The emitter of the horizontal output transistor 7, the anode of the horizontal damper diode 10 and the other end of the horizontal resonance capacitor 11 are directly grounded in common, whereas the other end of the horizontal deflection coil 12 is grounded through a horizontal S-shape correcting capacitor 13. As described above, a horizontal deflection output circuit is configured by the horizontal output transistor 7, the horizontal choke coil 8, the horizontal ~Amper diode 10, the horizontal resonance capacitor 11, the horizontal deflection coil 12 and the horizontal S-shape correcting capacitor 13. Thus, the horizontal deflection circuit is composed of this horizontal deflection output circuit and the aforementioned horizontal driving circuit.
In the above-mentioned prior art circuit, the collector of the horizontal regulation transistor 9 is supplied with a horizontal deflection voltage B2.
A description of the operation and function of the above-mentioned horizontal deflection output circuit per se is omitted here, because they are well known and have no relationship to the operation of the raster distortion correcting function. Thus, only the operation and function of the raster distortion correction part of the horizontal deflection circuit will be explained in the following paragraphs.
The phase relationship between the horizontal synchronisation signal of a computer and the display signal image region varies with the computer.
Therefore, in order to center the displayed signal image on the raster, a measure as shown in FIG. 2 has conventionally been taken. Referring to the circuit of FIG. 2, a horizontal oscillation signal ~a" as shown by FIG. 3 (a) is supplied from the horizontal oscillator circuit 1 to the delay circuit 2. Then, the phases of an output signal "b" as shown by FIG. 3 (b) from the delay circuit 2 and a horizontal synchronization signal "c" as s shown by FIG. 3 (c) are compared with each other. Thereby, the horizontal AFC circuit 6 is made to adjust the delay time tl of the delay circuit 2 in the circuitry shown in FIG. 2. As described, the horizontal drive transformer 4 is supplied with a constant stabilized voltage Bl in this conventional circuitry. Thus, when a horizontal trapezoid correction as shown by FIG. 4 or a horizontal pincushion correction as shown by FIG. 5 is applied to the picture, the collector current i2 of the horizontal output transistor 7 varies with a vertical deflection period l/fv, as shown by FIGS. 6 and 7, respectively. In that situation, since the Ib end (i.e. the end value of the base current il over a predetermined time period) shown by FIG. 3 (d) is constant, the driving condition of the horizontal output transistor 7 is caused to vary with the vertical deflection period. In FIGS. 6 and 7. fH indicates the horizontal deflection frequency and fV
indicates the vertical deflection frequency.
In the previously described conventional circuit, an electric charge accumulating time t2 shown by FIG. 3 (e) of the horizontal output transistor 7 varies with the vertical deflection period, thereby varying the phase relationship between the horizontal synchronization signal c and a horizontal deflection output pulse e (which is the collector voltage of the horizontal output transistor 7), hence varying the vertical deflection period. Therefore, the circuit has a drawback that the displayed rasters are distorted as shown by the broken lines in FIGS. 4 and 5, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a circuit diagram showing a preferred embodiment of the horizontal deflection circuit in accordance with the present invention, wherein the same reference symbols and numerals as those used in the above discussion of the conventional circuit, are used for designating the same or similar components, and their descriptions are omitted here.
In FIG. 1, a horizontal driving voltage modulation circuit 21 is interposed between the voltage supply terminal of the primary winding of the horizontal drive transformer 4 and the emitter of the horizontal regulation transistor 9. More particularly, the emitter of the horizontal regulation transistor 9 is grounded through a variable resistor 22 whose variable terminal is connected to the base of the voltage supply transistor 24 and to resistors 25 and 26 at their connection point through a capacitor 2042~80 23 for transferring only the alternating current component. The collector of the voltage supply transistor 24 is connected to a collector voltage supply terminal B3 and is grounded through the resistors 25 and 26. The emitter of the voltage supply transistor 24 is connected to the voltage supply end of the primary coil of the horizontal drive transformer 4 through a resistor 27 and is grounded through a filter capacitor 28, and the emitter itself is grounded through a resistor 29.
By arranging the circuit as previously described, when a trapezoid correction is performed on the raster or picture as shown by FIG. 4, a signal of vertical saw-tooth waveform g appears as the emitter voltage of the horizontal regulation transistor 9. This waveform also appears as a vertical deflection period alternating current component of the emitter voltage at the voltage supply transistor 24, thus causing the voltage supplied to the horizontal driving transformer 4 to be modulated with the vertical saw-tooth wave signal g'.
Accordingly, the Ib end of the base current il of the horizontal output transistor 7 is caused to vary with the vertical deflection period, while the driving condition of the horizontal output transistor 7 is always kept constant instead of being varied with the vertical deflection period. As previously described, the electric charge accumulating time expressed as t2 in FIG. 3 (e) can also always be maintained constant, thus preventing inclination of the vertical line as indicated by the broken line in FIG. 4 and maintAining it both vertical and straight, even if the trapezoid correction is applied. It may safely be said that the same or similar advantages will also be obtained in the case of performing the pincushion correction.
In addition to the foregoing, the delay time tl of the delay circuit 2 is made adjustable from outside, thus rendering the width adjustment of the picture or raster possible by adjustment of the delay time tl.
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
Claims (2)
1. A horizontal deflection circuit which comprises; horizontal automatic frequency control means for outputting a horizontal oscillation signal whose frequency is controlled to a predetermined frequency, and modulation means for modulating a voltage to be supplied to a driving transformer, which is driven by said horizontal oscillation signal and drives a horizontal deflection output switching device in a horizontal deflection output circuit, in compliance with a vertical synchronization alternating current component of a voltage supplied to said horizontal deflection output circuit.
2. A horizontal deflection circuit for a cathode ray tube display terminal, which comprises:
i) a delay circuit for delaying a horizontal oscillation signal, ii) a horizontal automatic frequency control circuit which outputs a comparison output signal by comparing a phase of a delayed signal from said delay circuit with a phase of a horizontal synchronization signal, and causes a horizontal oscillation circuit to output said horizontal oscillation signal whose frequency is controlled at said horizontal synchronization signal frequency by said horizontal comparison output signal; and iii) a horizontal driving voltage modulation circuit interposed between an output end of a horizontal regulation transistor and a voltage supply terminal of a driving transformer, which is driven by said horizontal oscillation signal and drives a horizontal deflection output switching device in a horizontal deflection output circuit;
said horizontal driving voltage modulation circuit comprising:
a) a potentiometer connected between an output end of said horizontal regulation transistor and reference ground potential;
b) a voltage supply transistor for supplying said driving transformer with a voltage;
c) a capacitor interposed between a variable terminal of said potentiometer and the base of said voltage supply transistor;
d) base-bias setting means for setting a base-bias of said voltage supply transistor; and e) an integrating circuit interposed between the output end of said voltage supply transistor and said driving transformer.
i) a delay circuit for delaying a horizontal oscillation signal, ii) a horizontal automatic frequency control circuit which outputs a comparison output signal by comparing a phase of a delayed signal from said delay circuit with a phase of a horizontal synchronization signal, and causes a horizontal oscillation circuit to output said horizontal oscillation signal whose frequency is controlled at said horizontal synchronization signal frequency by said horizontal comparison output signal; and iii) a horizontal driving voltage modulation circuit interposed between an output end of a horizontal regulation transistor and a voltage supply terminal of a driving transformer, which is driven by said horizontal oscillation signal and drives a horizontal deflection output switching device in a horizontal deflection output circuit;
said horizontal driving voltage modulation circuit comprising:
a) a potentiometer connected between an output end of said horizontal regulation transistor and reference ground potential;
b) a voltage supply transistor for supplying said driving transformer with a voltage;
c) a capacitor interposed between a variable terminal of said potentiometer and the base of said voltage supply transistor;
d) base-bias setting means for setting a base-bias of said voltage supply transistor; and e) an integrating circuit interposed between the output end of said voltage supply transistor and said driving transformer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPHEI2-136309 | 1990-05-25 | ||
| JP13630990A JPH0435271A (en) | 1990-05-25 | 1990-05-25 | Horizontal deflection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2042480A1 CA2042480A1 (en) | 1991-11-26 |
| CA2042480C true CA2042480C (en) | 1995-06-20 |
Family
ID=15172186
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2042480 Expired - Fee Related CA2042480C (en) | 1990-05-25 | 1991-05-13 | Horizontal deflection circuit |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH0435271A (en) |
| CA (1) | CA2042480C (en) |
| DE (1) | DE4116883C2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0639570A (en) * | 1993-04-28 | 1994-02-15 | Calsonic Corp | Method for welding metal honeycomb carrier |
| US5798621A (en) * | 1996-03-18 | 1998-08-25 | Thomson Consumer Electronics, Inc. | Horizontal deflection circuit with raster correction |
| US6081078A (en) * | 1996-05-17 | 2000-06-27 | Thomson Consumer Electronics, Inc. | Vertical deflection circuit with raster correction |
| JPH11197519A (en) | 1998-01-08 | 1999-07-27 | Honda Motor Co Ltd | Metallic carrier for exhaust gas purifying catalyst |
| JP3978949B2 (en) | 1999-09-29 | 2007-09-19 | ソニー株式会社 | Disc recording and / or playback device |
| KR100657622B1 (en) * | 2005-07-13 | 2006-12-14 | 한국철도기술연구원 | The steering bogie for railway vehicle |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0693755B2 (en) * | 1987-03-30 | 1994-11-16 | 株式会社日立製作所 | Television distortion correction circuit |
-
1990
- 1990-05-25 JP JP13630990A patent/JPH0435271A/en active Pending
-
1991
- 1991-05-13 CA CA 2042480 patent/CA2042480C/en not_active Expired - Fee Related
- 1991-05-23 DE DE19914116883 patent/DE4116883C2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE4116883A1 (en) | 1991-11-28 |
| JPH0435271A (en) | 1992-02-06 |
| DE4116883C2 (en) | 1994-09-29 |
| CA2042480A1 (en) | 1991-11-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |