JPH0974496A - Horizontal raster width digital controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately execute horizontal raster display width control in the transient state at changeover of a frequency of a horizontal synchronizing signal or at application of power or the like. SOLUTION: A difference signal between an output of a horizontal deflection circuit unit 160 and a desired horizontal width signal is given to an A/D converter 140, in which the signal is converted into a digital signal, and it is outputted to a DSP(digital signal processing means) 110. Feedback control for raster width is executed by digital arithmetic operation in the DSP 110. Moreover, the DSP 110 provides an output of the result of arithmetic operation to a D/A converter 120, in which the signal is converted into an analog signal and it is fed to a horizontal deflection unit 160, where a power supply voltage fed to a deflection yoke 4 is controlled.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cathode ray tube (hereinafter,
The present invention relates to a horizontal raster width digital controller for controlling the raster display width of a display device equipped with a CRT).

[0002]

2. Description of the Related Art FIG. 23 is a block diagram showing the configuration of a conventional horizontal raster width analog control device. In the figure, 1
Is a horizontal output choke transformer, 2 is a horizontal output transistor, 3 is a damper diode, 4 is a CRT deflection yoke,
5 is a capacitor that causes resonance with the deflection yoke 4, 6
Is a capacitor for supplying energy for resonance, 7 is a diode for rectifying the output voltage on the secondary side of the horizontal output choke transformer 1, 8 is a capacitor for smoothing, and 9 is rectified and smoothed by the diode 7 and the capacitor 8. Low-pass filter for removing the ripple of the voltage
Is a differential amplifier which outputs a difference between a signal from a D / A converter (not shown) for controlling the horizontal raster width and a horizontal width feedback voltage from the low-pass filter 9, 11
Is a horizontal deflection voltage control device for controlling the output voltage according to the output signal from the differential amplifier 10.

Next, the operation will be described. Electric power for horizontal deflection is supplied to the deflection yoke 4 by the horizontal output transistor 2, the damper diode 3, and the capacitors 5 and 6. At this time, the magnitude of the deflection current flowing through the deflection yoke 4 is controlled based on the electric power supplied from the primary winding of the horizontal output choke transformer 1. That is, the raster width is controlled by the voltage output from the horizontal deflection voltage controller 11.

The voltage V _{cp of the} collector pulse applied to the collector of the horizontal output transistor 2 also increases in proportion to the magnitude of the horizontal deflection current flowing in the deflection yoke 4, so that the secondary side of the horizontal output choke transformer 1 is increased. The voltage rectified and smoothed by the diode 7 and the capacitor 8 from the winding reflects the magnitude of the horizontal deflection current flowing in the deflection yoke 4, that is, the horizontal deflection width. The voltage rectified and smoothed by the diode 7 and the capacitor 8 is attenuated by the low-pass filter 9 to have a component of a predetermined frequency or higher, and is input to one input terminal of the differential amplifier 10. A control target value in which the distortion of the horizontal width in the vertical direction is corrected is input to the other input terminal of the differential amplifier 10 from a D / A converter (not shown). The differential amplifier 10 takes the difference between these two input values, and controls the horizontal deflection voltage control device 11 by this difference signal to vary the voltage + B applied to the horizontal output choke transformer 1 to change the horizontal raster width. The feedback control of is realized.

Further, a display device for converting a raster width into a digital signal for control is disclosed in Japanese Patent Laid-Open No. 4-82480.

FIG. 24 is a block diagram showing the structure of this conventional display device. In FIG. 24, 501 is a computer, 502 is a luminance signal generating circuit, 503 is a dot clock generating circuit, 504 is a cathode ray tube, 505 is a changing yoke, 506 is a horizontal amplitude control circuit, 507 is a horizontal deflection circuit, and 508 is a vertical deflection circuit. 509 is a vertical amplitude control circuit, 510 is a cathode ray tube display, and 511 is a video board for producing a signal for sending the output information of the computer 501 to the cathode ray tube display 510.

In the video board 511, 512 is a timing signal generator circuit for producing a vertical synchronizing signal, a horizontal synchronizing signal, a front porch signal, and a back porch signal by a dot clock signal, and 513 is a luminance of a luminance signal rather than a front porch signal and a back porch signal. It is a white pattern signal generator circuit that creates a white pattern signal in which information is white information from the beginning to the end.

In the cathode ray tube display 510, 5
A deflection current change width detection circuit 15 detects the change width of the sawtooth wave current from the horizontal deflection circuit 507 during the pulse width period of the white pattern signal sent from the white pattern signal generator circuit 513. Reference numeral 531 is a current / voltage conversion circuit for converting into a voltage proportional to the current detected by the deflection current change width detection circuit 515, and reference numeral 519 is analog / digital for converting an analog voltage output from the current / voltage conversion circuit 531 into digital. Conversion circuit, 529
Is a change width reference voltage value generation circuit for generating a change width reference value of the sawtooth wave current from the horizontal deflection circuit 507 within the period of the pulse width of the white pattern signal, and 528 is output from the change width reference voltage value generation circuit 529. Difference detection circuit for detecting the difference in the change width output from the analog / digital conversion circuit 519 with respect to the change width reference value, and a jitter correction circuit 516 for correcting the jitter in the change width output from the width difference detection circuit 528. Reference numeral 517 denotes a digital / analog conversion circuit which converts the difference in the variation width after the jitter correction into an analog voltage and outputs the analog voltage to the horizontal amplitude control circuit 506.

A deflection current change width detection circuit 518 detects a change width of the sawtooth wave current from the vertical deflection circuit 508 within the pulse width period of the white pattern signal sent from the white pattern signal generator circuit 513. To do. 53
Reference numeral 2 denotes a current / voltage conversion circuit for converting a voltage proportional to the current detected by the deflection current change width detection circuit 518, 52
Reference numeral 7 denotes an analog / digital conversion circuit for converting analog of the voltage output from the current / voltage conversion circuit 532 into digital, and 514 denotes the sawtooth wave current from the vertical deflection circuit 508 within the pulse width period of the white pattern signal. Change width reference voltage value generation circuit 530 for generating change width reference value
Is a width difference detection circuit for detecting the difference in the change width output from the change width reference voltage value generation circuit 514, 520 is a jitter correction circuit for correcting the jitter in the change width output from the width difference detection circuit 530, 521 Is a digital / analog conversion circuit that converts the difference in the variation width after jitter correction into an analog voltage and outputs the analog voltage to the vertical amplitude control circuit 509.

With respect to the display device configured as described above, an operation of adjusting the width of the image display area so as not to extend beyond the screen will be described below.

In the video board 511, the timing signal generator circuit 512 uses the dot clock signal output from the dot clock generation circuit 503 to generate the signal shown in FIG.
As shown in 5 (b) (c) (d) (e), a horizontal synchronizing signal, a vertical synchronizing signal, a back porch signal, and a front porch signal are created. In the white pattern signal generator circuit 513, from the front porch signal and the back porch signal, as shown in FIG. 25 (f), a white pattern signal with all white information from the beginning to the end of the luminance information of the luminance signal is made to produce a cathode ray tube. Output to the display 510.

In the cathode ray tube display 510, when adjusting so that the width of the display area of the image in the horizontal direction does not extend beyond the screen, as shown in FIG.
The current value A of the sawtooth wave current supplied to the deflection yoke 505 by the horizontal deflection circuit 507 by the rising edge trigger of the white pattern signal sent from the sawtooth wave current value by the falling edge trigger of the white pattern signal. B is detected, and the variation width E of the sawtooth wave current supplied to the deflection yoke by the horizontal deflection circuit 507 within the period of the pulse width of the white pattern signal from these A and B values is set to E = A + B, and the deflection current variation width is set. Output from the detection circuit 515. The change width E of the current is changed from the current value to the voltage value by the current / voltage conversion circuit 531 and the analog / digital conversion circuit 51
9 is converted from analog to digital, and the width difference detection circuit 528 detects the difference in the change width with respect to the change width reference value output from the change width reference voltage value generation circuit 529. The difference between the change widths is corrected by the jitter correction circuit 516, and the digital / analog conversion circuit 51
7 is converted into an analog voltage by the horizontal amplitude control circuit 5
06. In the horizontal amplitude control circuit 506, the power supply voltage of the horizontal deflection circuit 507 is varied according to the applied voltage, and the amplitude of the sawtooth wave current generated by the horizontal deflection circuit 507 is changed to display the width of the horizontal display area of the image. Is adjusted.

When the width of the vertical display area of the image is adjusted so as not to extend beyond the screen, the rising edge of the white pattern signal at the top of the screen sent from the video board 511 as shown in FIG. The current value C of the sawtooth wave current supplied to the deflection yoke 505 by the vertical deflection circuit 508 by the trigger is changed to the current value D of the sawtooth wave current by the edge trigger of the falling edge of the white pattern signal at the bottom of the screen.
And the change width I of the sawtooth wave current supplied to the deflection yoke 505 by the vertical deflection circuit 508 within the period of the pulse value of the white pattern signal from these C and D values is set as I = C + D. Output from the detection circuit 518. The change width I of the current is changed from the current value to the voltage value by the current / voltage conversion circuit 532, and the analog / digital conversion circuit 52
7, the analog-to-digital conversion is performed, and the width difference detection circuit 530 detects the difference in the change width from the change width reference value output from the change width reference voltage value generation circuit 514. The difference between the change widths is corrected by the jitter correction circuit 520, and the digital / analog conversion circuit 52
1 is converted into an analog voltage by the vertical amplitude control circuit 5
09 is applied. The vertical amplitude control circuit 509 changes the power supply voltage of the vertical deflection circuit 508 according to the applied voltage and changes the amplitude of the sawtooth wave current generated by the vertical deflection circuit 508 to display a vertical image display area. The width is adjusted.

[0014]

Since the conventional horizontal raster width analog controller is constructed as described above, the parabolic modulation of the period of the vertical synchronizing signal for correcting the pincushion distortion of the raster is superimposed on the feedback system. Since it is difficult to set the cut-off frequency of the low-pass filter 9 and the like, and when the horizontal synchronizing frequency is switched when a plurality of horizontal synchronizing frequencies are used for switching, or when a transient phenomenon such as power on / off occurs, There is a problem that stress is applied by applying an overvoltage to the output transistor 2.

Further, in the above-mentioned conventional digital display device for controlling the horizontal raster width, since the variation width of the deflection current is directly A / D converted, a high resolution A / D converter is required, and the A / D converter is required. A multi-bit microcomputer or the like is required to process the converted digital data, which causes a problem of high cost.

The present invention has been made to solve the above problems, and enables horizontal raster display width control to be performed accurately in response to changes in the horizontal synchronizing frequency without being affected by pin winding correction and the like. In addition, it is an object of the present invention to provide a horizontal raster display width control device capable of preventing stress on components such as the horizontal output transistor and further suppressing manufacturing costs.

[0017]

According to a first aspect of the invention, there is provided a horizontal raster width digital control device based on a deflection yoke for horizontally deflecting an electron beam of a cathode ray tube and an input control signal. Horizontal deflection voltage control means for controlling and outputting a power supply voltage for applying a voltage to the deflection yoke, and a voltage based on the power supply voltage output from the horizontal deflection voltage control means is applied to the deflection yoke at the timing of the horizontal synchronizing signal. A horizontal output transistor, a voltage measuring means for measuring and outputting a first signal corresponding to a collector pulse voltage of the horizontal output transistor, and a difference signal between the first signal and a second signal indicating a desired horizontal width. A differential amplifier that outputs a signal, an analog / digital signal converter that converts the output from the differential amplifier into a digital signal, and
Digital signal processing means for inputting the digital signal output from the digital signal converting means, performing feedback calculation processing for controlling the horizontal width of the raster, and outputting the digital signal of the calculation result, and the digital signal processing means for outputting the digital signal. Digital-to-analog conversion means for converting a digital signal to an analog signal, and a control signal for controlling the power supply voltage based on the analog signal output from the digital-to-analog conversion means, and outputs it to the horizontal deflection voltage control means. And a voltage control signal generating means for

In the horizontal raster width digital control device according to the present invention, the analog / digital signal converting means samples and holds the analog output from the differential amplifying means at the timing of the vertical synchronizing signal. It is a thing.

According to a third aspect of the present invention, there is provided a horizontal raster width digital control device, wherein a raster width input means for inputting a desired horizontal raster width and a desired horizontal raster width input by the raster width input means are used. And a raster width signal generating means for generating two signals.

In the horizontal raster width digital controller according to the present invention, the output of the analog / digital signal converting means becomes a predetermined converged digital value when the control of the feedback calculation processing of the digital signal processing means converges. Thus, the feedback calculation process is executed.

In the horizontal raster width digital control device according to the present invention, the first feedback calculation process having a fast control speed is executed a predetermined number of times immediately after the digital signal processing means is turned on or the horizontal synchronizing frequency is switched. However, after that, the second feedback calculation process having a slow control speed is repeatedly executed.

According to a sixth aspect of the present invention, there is provided a horizontal raster width digital control device in which the digital signal value outputted from the analog / digital signal converting means is converged into a digital value in the first feedback arithmetic processing of the digital signal processing means. Is divided into a plurality of areas with reference to, and feedback calculation processing with different control speeds is performed for each area.

According to a seventh aspect of the present invention, there is provided a horizontal raster width digital control device which comprises a correction wave generating means for generating a correction wave for correcting the horizontal width of a raster at a cycle of a vertical synchronizing signal, and the correction wave for the digital signal. A signal addition means for adding to the analog signal output from the analog conversion means, wherein the voltage control signal generation means generates a control signal for controlling the power supply voltage based on the signal output from the signal addition means Then, the horizontal deflection voltage control means is output.

In the horizontal raster width digital control device according to the present invention, the correction wave generation means stops the generation of the correction wave immediately after the switching of the horizontal synchronization frequency, and the voltage value output from the horizontal deflection voltage control means. The correction wave generating means outputs a signal of a predetermined voltage so that

In the horizontal raster width digital control device according to the present invention, the voltage value output from the horizontal deflection voltage control means is lowered for a predetermined period immediately after the power is turned on or the horizontal synchronizing frequency is switched. The digital signal processing means is configured to send digital data to the digital / analog signal converting means.

In the horizontal raster width digital control device according to the tenth aspect of the present invention, the feedback calculation processing of the digital signal processing means includes the horizontal synchronizing signal frequency as a parameter so as to absorb the control fluctuation due to the difference in the horizontal synchronizing signal frequency. It is configured as follows.

In the horizontal raster width digital control device according to the invention as defined in claim 11, the digital signal processing means is constituted by the analog / digital signal converting means and the vertical synchronizing signal 1 is supplied.
The feedback calculation process is executed using the digital data converted and output before the cycle.

According to a twelfth aspect of the present invention, in the horizontal raster width digital control device, the analog / digital signal converting means is delayed from the timing of the vertical synchronizing signal by a half cycle of the vertical synchronizing signal, and the analog from the differential amplifying means. It is configured to sample and hold the output.

In the horizontal raster width digital control device according to the thirteenth aspect of the present invention, the analog / digital signal converting means is configured to sample and hold the analog output from the differential amplifying means at the timing of the horizontal synchronizing signal. It was done.

According to a fourteenth aspect of the present invention, there is provided a horizontal raster width digital control device, a correction wave generating means for generating a correction wave for correcting the horizontal width of a raster in a cycle of a vertical synchronizing signal, a correction wave and a second correction wave. And a signal that is added to the differential amplification means and outputs the added signal to the differential amplification means.

According to a fifteenth aspect of the present invention, there is provided a horizontal raster width digital control device which comprises a current control means for controlling the amplitude of the base current of the horizontal output transistor based on a change in the analog signal output from the digital-analog conversion means. It is equipped with.

According to a sixteenth aspect of the present invention, there is provided a horizontal raster width digital control device in which the analog signal output from the digital-analog conversion means is judged to be abnormal when the analog signal is not within a predetermined range. It is provided with a protection means for cutting off the power supply of.

In the horizontal raster width digital control device according to the seventeenth aspect of the present invention, when the value of the analog signal output from the digital-analog converting means is not within the predetermined range, it is judged to be abnormal and the user is informed. It is provided with a warning means for giving a warning.

According to the eighteenth aspect of the present invention, in the horizontal raster width digital control device, when the value of the output from the differential amplifying means is not within the predetermined range, it is judged as abnormal and the power supply of the horizontal raster width digital control device. It is provided with a protection means for disconnecting.

According to a nineteenth aspect of the present invention, in the horizontal raster width digital control device, when the value of the output from the differential amplifying means is not within a predetermined range, it is judged to be abnormal and a user is warned. It is provided with a warning means.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a block diagram showing the configuration of a horizontal raster width digital control device according to a first embodiment of the present invention. In the figure, the same parts as those of the conventional example of FIG. Reference numeral 100 is a CP that controls each part of the horizontal raster width digital control device.
U (raster width input means), 101 is a rotary encoder (raster width input means) for inputting a desired horizontal raster width signal H-SIZE _ref from the user to the CPU 100, 1
Reference numeral 10 denotes a digital signal processor (hereinafter, referred to as DSP) (digital signal processing means, correction wave generation means) that executes calculations such as feedback control of horizontal raster width and correction processing of raster width in a vertical cycle. DS
D / A converter (digital / analog signal conversion means, raster width signal generation means) for converting the digital feedback control signal calculated by P110 and the digital horizontal raster width signal H-SIZE _ref sent from the DSP 110 into an analog signal. ), 130 is D / A
The horizontal raster width signal H- output from the converter 120
An adder (raster width signal generation means) for adding SIZE _ref and a signal + B _ref indicating the height of voltage + B output from the horizontal deflection voltage control device (horizontal deflection voltage control means) 11, 140 is a differential amplifier ( A / which converts the analog signal output from the differential amplifier 10) into a digital signal
D converter (analog / digital signal conversion means),
Reference numeral 150 denotes output terminals A1 and A of the D / A converter 120.
2, an inverting adder (signal adding means) for inverting and adding the signals output from A3 to a predetermined weight, 200 is a DS
A D / A converter that converts the parabolic correction data for pincushion distortion correction output from P110 to an analog signal, and an inversion 151 that inverts and adds the parabolic correction wave for pincushion distortion correction output from the D / A converter 200. An adder (signal adding means) 152 is a comparator (voltage control signal generating means) 153 which compares the output of the inverting adder 151 with the horizontal synchronizing sawtooth wave H-SAWTOOTH and outputs a pulse corresponding to the comparison result. 154 is a comparator 152
, Which is a transistor forming a buffer circuit for buffering the output of, and 160 is a horizontal deflection circuit unit. In addition, 7
A and 7B are horizontal output choke transformers (voltage measuring means)
1 is a diode (voltage measuring means) for rectifying the secondary winding voltage of No. 1 Reference numeral 170 is a transistor for an emitter follower that buffers the voltage rectified by these diodes, and 9a is a low-pass filter that allows only a signal of a predetermined frequency or less of the emitter output of the transistor 170 to pass. The output from the low-pass filter 9a is input to the differential amplifier 10.

Next, the operation will be described. The horizontal raster width is proportional to the current I _DY flowing through the deflection yoke 4, and the current I _DY is proportional to the output voltage + B of the horizontal deflection voltage controller 11.
Furthermore, the current I _DY is inversely proportional to the horizontal sync frequency. Further, the collector pulse voltage V _cp applied to the collector of the horizontal output transistor 2 changes in proportion to the current I _DY . Furthermore, since the collector pulse voltage V _cp is reflected in the value obtained by rectifying the secondary side winding output of the horizontal output choke transformer 1, the horizontal raster width can be controlled by measuring this rectified value (first signal). it can. Therefore, the secondary winding output of the horizontal output choke transformer 1 is connected to the diodes 7A and 7B.
Is rectified, smoothed by the capacitor 8 (voltage measuring means), sent to the transistor 170, buffered by the emitter follower, and input to one input terminal of the differential amplifier 10.

Further, the signal + B _ref indicating the output voltage + B of the horizontal deflection voltage controller 11 is also output from the D / A converter 120 according to the horizontal synchronizing frequency. The horizontal raster width signal H-SIZE _ref and the signal + B _ref are added by the adder 130, and the added signal serves as a horizontal raster width reference signal (second signal).

FIG. 2 shows the signal + B _ref and the horizontal synchronizing frequency f _H.
It is a graph which shows the relationship with. 3 is a graph showing the relationship between the voltage + B and the horizontal synchronizing frequency f _H when the horizontal raster width H-SIZE desired by the user is the median value, and FIG. 4 is the horizontal raster desired by the user. Width H-SI
FIG. 9 is a graph showing the relationship between the voltage + B and the horizontal synchronization frequency f _H for each of the minimum value, the median value, and the maximum value of ZE. As shown in FIG. 3, the signal + B _ref is such that the horizontal width of the raster becomes constant at each frequency f _H1 , f _H2 , and f _H3 when the desired horizontal raster width H-SIZE is the median value of the variable range. + B _ref has been decided. For other frequencies, the corresponding signal + B _ref is determined by linear interpolation. These data are D
It is transferred from the SP 110 to the D / A converter 120 and converted into an analog signal.

The output signal of the adder 130 is the differential amplifier 10
Is input to one of the input terminals. The output of the low-pass filter 9a is input to the other input terminals, and the difference signal between these signals is amplified by the differential amplifier 10 and output. The output signal of the differential amplifier 10 is the A / D converter 1
It is input to 40 and converted into a digital signal. A / D
In the converter 140, the timing of the clock synchronized with the vertical synchronization signal V-SYNC input to the DSP 110,
That is, sample hold and A / D conversion are performed at the timing of vertical synchronization. The digital output output from the A / D converter 140 is D via the data line.
Input to SP110. For example, A / D converter 1
40 with 8-bit resolution, input voltage from "0" to V
_{When using the ref} (A / D converter reference voltage), the DSP 110 is set so that the digital output value of the A / D converter 140 is always the center value "80H".
Controlled by.

The control data from the DSP 110 is output to the D / A converter 120 via the serial transfer line. The control output data has different resolutions, and the analog output terminal A1 of the D / A converter 120,
It is output from A2 and A3. The signals output from these terminals are weighted by the difference in the values of the resistors 121, 122, 123 and the like, and are inverted and added by the inverting adder 150. DSP1 is added to the signal output from the inverting adder 150.
For example, the parabolic correction wave output from 10 is inverted and added by the inverting adder 151. Comparator 152
, The output of the inverting adder 151 is compared with the sawtooth wave H-SAWTOOTH of the horizontal synchronization period, and a pulse signal train corresponding to the magnitude of the output of the inverting adder 151 is generated. This signal train is sent to the horizontal deflection voltage controller 11 through the buffer circuit formed by the transistors 153 and 154, and the DC 180V is chopper-controlled to generate an appropriate voltage + B.

The operation of the DSP 110 will be mainly described below. FIG. 5 is a flowchart showing the main routine of the horizontal raster width control algorithm in the DSP 110. When the display device is powered on, the DSP1
After initializing the inside of 10, for example, clearing the built-in RAM area (step ST501), stress reduction processing is executed (step ST502). This stress reduction processing is performed as follows.

Immediately after the power is turned on, it is input to the comparator 152.
The horizontal sawtooth wave does not have a constant cycle
Become. Therefore, when the period of the horizontal sawtooth wave is very long,
The voltage + B becomes high, and the
Voltage on the rectifier V_cpThe higher the horizontal output transition
The stress of star 2 increases extremely. This phenomenon is shown in FIG.
This will be described with reference to FIGS. 9 and 10. FIG. 8 shows the comparator 152 and
3 is a circuit diagram showing a horizontal deflection voltage control circuit 11 and FIG. Figure 9
Shows the waveform of the input / output signal of the comparator 152 in the steady state.
FIG. FIG. 10 shows the comparator immediately after the power is turned on.
5 is a waveform diagram showing the waveform of an input / output signal of 152. FIG. In Figure 9
Compared to the horizontal sawtooth wave B in the steady state shown in FIG.
When the horizontal sawtooth wave B has a longer period as shown in 0
The low period Tc of the output C of the comparator 152 is shown in FIG.
It becomes longer than the low period Tc in the steady state. Low
During the period Tc, it is composed of transistors such as FETs.
The switching element 11a is turned on and the inductor 1
Energy is stored in 1b during the period Tc. Follow
Therefore, the longer the period Tc, the more the voltage + B rises.
And The cycle of this horizontal sawtooth wave and the horizontal shown in Fig. 1.
The drive cycle of the output transistor 2 is the same cycle.
Therefore, if the voltage + B rises, the collector voltage V _cpAlso rises
Will be done.

From the above, as the processing immediately after the power is turned on,
The DSP 110 controls the output voltage A of the inverting adder 151 to be a voltage equal to or lower than the minimum value of the sawtooth wave B input to the comparator 152. Since the processing speed of the DSP 110 is high, the initialization step ST501 shown in FIG. 5 is performed at high speed, and the above control of the output voltage A can be performed in an extremely short time. As shown in the graph of FIG. 2, the signal + B _ref is D so that the D / A converter 120 outputs a voltage corresponding to the input horizontal synchronizing frequency.
Digital data from SP110 is D / A converter 1
20 is transferred. In addition, the rotary encoder 101
D / A when the CPU 100 detects the pulse of
The digital data is transferred to the converter 120, and the horizontal raster width signal H-SIZE _ref is transferred to the D / A converter 120.
Output from

That is, immediately after the power is turned on, the raster width feedback control by the DSP 110 is not intentionally performed on the designated reference output, that is, the output of the adder 130. After a predetermined time has passed, the adder 1
Control for causing the signal output from the terminal HO of the horizontal deflection circuit unit 160 to follow the reference signal output from 30, that is, feedback control is started.
This predetermined period is determined in advance in consideration of the time during which the period of the horizontal sawtooth wave input to the comparator 152 in FIG. 1 stabilizes. The horizontal sawtooth wave H-SAWTOOTH is generated by a horizontal synchronization signal input from the outside or a trigger by a free-running frequency by an internal oscillator.

Next, a horizontal sawtooth wave H-SAWTOOT
The digital control of the horizontal width after the H cycle becomes stable will be described. Output terminal A3 of D / A converter 120
Is used as an offset voltage of the output voltage of the output terminals A1 and A2. As a result, the followability of the raster horizontal width control at each horizontal synchronization frequency can be improved. The output voltages from the output terminals A1 and A2 are weighted by the resistors 121 and 122 and added by the inverting adder 150. Further, the weighting on the hardware by the constant ratio must match the weighting on the software inside the DSP 110. If they do not match, a control discontinuity point is created and a point where the width does not change smoothly when the raster width changes occurs.

Next, the horizontal raster width signal H-SI desired by the user which is input by the rotary encoder 101.
ZE _ref is input from the CPU 100 to the DSP 110,
The data of this horizontal raster width signal H-SIZE _ref is DS
It is transferred to the D / A converter 120 via P110 and converted into an analog horizontal raster width signal H-SIZE _ref signal (step ST503). After that, every time the vertical synchronization signal V-SYNC is input (step ST50
4) The subroutine SUB1 is called (step ST505). The operation of the subroutine SUB1 will be described later. After the subroutine SUB1 is called a predetermined number of times (step ST506), the horizontal raster width signal H-SIZE _ref desired by the user input by the rotary encoder 101 is output from the CPU 100 to the DSP1.
10 is input to the horizontal raster width signal H-SIZE.
_{The ref} data is transferred to the D / A converter 120 and converted into an analog horizontal raster width signal H-SIZE _ref signal (step ST507). After that, every time the vertical synchronization signal V-SYNC is input (step ST50
8) Then, the subroutine SUB2 is repeatedly called this time (step ST509). When the switching of the horizontal synchronizing frequency f _H is detected by an interrupt or the like, the stress reducing process (step ST510) is executed, and the process proceeds to step ST503. This step S
The stress reduction process of T510 will be described in detail later.

Next, the operation of the subroutine SUB1 (first feedback calculation process) will be described. FIG. 6 is a flowchart showing the subroutine SUB1. A
A sample / hold pulse is sent from the DSP 110 to the / D converter 140, the difference between the two input signals of the differential amplifier 10 is A / D converted, and the corresponding digital signal is transferred to the DSP 110 via the data line. DS
P110 reads the digital output value of the A / D converter 140 (step ST601) and obtains an average value of a predetermined number of times, for example, an average value AVR of three times (step ST602). Also, the nth D / A converter 120
Let Y (n) be the addition output of the output terminals A1 and A2. Therefore, if the output value of this time is Y (n), the output value of the previous time is expressed as Y (n-1), and the output value of the previous two times is expressed as Y (n-2).

When the difference between the average value AVR of the predetermined number of digital outputs of the A / D converter 140 and the raster width feedback value is very large, that is, AVR> F0H.
Alternatively, when AVR <10H (step ST603, step ST604), Y (n) is calculated by the following equation (1).
Is calculated (step ST605). Y (n) = Y (n -1) -K1 (Y (n-1) -Y (n-2)) -K2 · f H · (AVR-80H). . . (1)

In step ST606 following step ST605, Y (n) is converted into XFH1 and XFH2,
Signals corresponding to XFH1 and XFH2 are output from the output terminals A1 and A2 of the D / A converter 120 (step S
T607).

Similarly, when the difference between the average value AVR and the raster width feedback value is medium, that is, 10
H ≦ AVR <70H or 90H <AVR ≦ F0H
If (steps ST603, ST604, ST60
8, ST609), Y (n) is calculated by the following equation (2) (step ST610). Y (n) = Y (n -1) -K3 · (Y (n-1) -Y (n-2)) -K4 · f H · (AVR-80H). . . (2)

Then, in step ST611, Y (n) is converted into XFH1 and XFH2, and the signals corresponding to XFH1 and XFH2 are output to the output terminal A1 of the D / A converter 120.
Output from A2 (step ST612).

When the control system is substantially converged, that is, 70H≤AVR <7EH, or 82H <AVR≤
In the case of 90H (steps ST603, ST604, ST
608, ST609, ST613, ST614) calculates Y (n) by the following equation (3) (step ST
615). Y (n) = Y (n-1) -K5. (AVR-80H). . . (3)

Then, in step ST616, Y (n) is converted into XFH1 and XFH2, and the signals corresponding to XFH1 and XFH2 are output to the output terminal A1 of the D / A converter 120.
Output from A2 (step ST617).

On the other hand, when the control system is converged, that is, when 7EH≤AVR≤82H (step ST60).
3, ST604, ST608, ST609, ST61
3, ST614), the process is directly returned without feedback control.

Next, the subroutine SUB2 (second feedback calculation process) will be described. FIG. 7 is a flowchart showing the subroutine SUB2. Similar to the subroutine SUB1, the digital data of the A / D converter 140 is read (step ST701) and A / D is read.
The average value AVR of the digital data output from D converter 140 is calculated (step ST702).

When the difference between the average value AVR of the predetermined number of digital outputs of the A / D converter 140 and the raster width feedback value is large, that is, when AVR <70H or AVR> 90H (step ST703, step ST704). Y (n) is calculated by the following equation (4) (step ST705). Y (n) = Y (n -1) -K6 (Y (n-1) -Y (n-2)) -K7 · f H · (AVR-80H). . . (4)

Then, in step ST705, Y (n) is converted into XFH1 and XFH2, and signals corresponding to XFH1 and XFH2 are output to the output terminal A1 of the D / A converter 120.
Output from A2 (step ST707).

When the control system is almost converged, that is, 70H≤AVR <7EH or 82H <AVR≤90H
In the case of (steps ST703, ST704, ST70
8, ST709), Y (n) is calculated by the following equation (5) (step ST710). Y (n) = Y (n -1) -K8 · f H · (AVR-80H). . . (5)

Then, in step ST711, Y (n) is converted into XFH1 and XFH2, and signals corresponding to XFH1 and XFH2 are output to the output terminal A1 of the D / A converter 120.
Output from A2 (step ST712).

On the other hand, when the control system is converged, that is, when 7EH≤AVR≤82H (step ST70).
3, ST704, ST708, ST709), the feedback control is not executed and the process returns.

In the equations (1) to (5), the speed and stability of the control system are determined by the values of the coefficients K1 to K8. Therefore, the loop gain of the loop that executes the subroutine SUB1 is set high by appropriately selecting the coefficients K1 to K8. On the other hand, the subroutine S
The coefficient is set so that the loop gain of the loop that executes UB2 is lower than the loop gain of the loop that executes the subroutine SUB1. Further, as shown in the flowchart of FIG. 5, since the loop gain of the subroutine SUB1 is set high, the number of loops is set in advance in order to prevent oscillation of the raster width.

Specifically, in the equations (1), (2) and (4), the smaller the values of the coefficients K1, K3 and K6 are,
The loop gain increases, and the loop gain increases as the values of the coefficients K2, K4, and K7 increase. Further, in equations (3) and (5), the loop gain increases as the values of the coefficients K5 and K8 increase.

Further, in the subroutine SUB1, the coefficient of the equation is set so that the control speed becomes slower in the order of the equation (1), the equation (2) and the equation (3). Further, in the subroutine SUB2, the coefficient of the equation is set so that the control speed becomes slower in the order of the equation (4) and the equation (5).

Further, in the equations (1), (2) and (4), the horizontal synchronizing frequency f _H is used as a parameter. That is,
The loop gain is controlled to be higher as the horizontal synchronizing frequency f _H is higher. Further, the A / D converter 140 and the D / A converter 120 have an 8-bit resolution that operates with a single 5 V power supply, and the output value of the A / D converter 140 is 80 H as the convergence value of the control system of this embodiment. Has been adopted.

The output terminal A1 of the D / A converter 120,
The output voltage from A2 is weighted by the following equation to become signals XFH1 and XFH2. Y (n) = XFH1 + 64 · XFH2 In this formula, the resolution ratio of the output voltages from the output terminals A1 and A2 is 1:64, but it may be set to another resolution ratio. However, it is necessary to match the resolution ratio in software in the DSP 110 with the resolution ratio in hardware from the output terminals A1 and A2.

Further, as described above, the A / D converter 1
40 sample and hold and A / D conversion were performed at the timing of the vertical synchronizing signal V-SYNC. For this reason,
As shown in FIG. 2, even if the voltage + B is modulated for the left and right pincushion distortion correction, the feedback control is performed in the area where the left and right pincushion distortion is not corrected, so that the raster width feedback control is not affected by the pincushion correction or the like. It can be performed. Further, as shown in FIG. 13, the left and right pincushion distortion correction is performed with the four vertices of the raster as fixed points.
Furthermore, the data of A / D conversion is delayed by one cycle and the DSP 11
If it is set to 0, an element having a slow conversion speed can be used for the A / D converter 140.

Further, by performing sampling and holding in the middle of the vertical synchronizing signal V-SYNC and the next vertical synchronizing signal V-SYNC, that is, by delaying by 1 / 2V,
As shown in FIG. 4, the left and right pincushion distortion correction is performed while keeping the horizontal width of the center portion of the raster constant.

Equation (4) of the subroutine SUB2,
In (5), the control that changes the loop gain is performed by using a coefficient different from the coefficient of the mathematical expression of the subroutine SUB1. In addition to this control, the average value A for using each formula
The stability of the control system may be changed by performing feedback control in a way of dividing the range of the VR value different from that of the subroutine SUB1.

Next, the horizontal synchronizing frequency f _H of the horizontal synchronizing signal
Stress reduction process (step ST51
0) will be described. When the horizontal synchronizing frequency f _H changes, the horizontal synchronizing frequency f _H is detected after the change in frequency is detected.
Is stable, or until a certain time elapses after the switching of the horizontal synchronizing frequency f _H is recognized, the output voltage from the output terminal A3 of the D / A converter 120 is set to the minimum value and the stress applied to the horizontal output transistor 2 is reduced. Reduce.
For example, in FIG. 11, the horizontal synchronization frequency f _H is f _HMAX
From f _H1 to f _H1 , the minimum horizontal sync frequency f _HMIN until the horizontal sync frequency stabilizes at f _H1 or until a certain amount of time elapses after the frequency change is recognized.
The voltage V _HMIN corresponding to is controlled to be output from the output terminal A3 of the D / A converter 120.

As a means for reducing stress when switching the horizontal synchronizing frequency f _H , the parabolic correction wave output from the DSP 110 is controlled to have a constant voltage for a predetermined period. As shown in FIG. 15, since it is not necessary to calculate the horizontal raster distortion correction waveform during the switching period of the horizontal synchronization frequency f _H and output the waveform, the DSP 110 generates the distortion correction waveform during the switching period of the horizontal synchronization frequency f _H. Output the highest voltage value possible. By doing so, the output voltage of the inverting adder 151 becomes a low voltage value, and the stress of the horizontal output transistor 2 is reduced.

Further, in the above-mentioned embodiment, the parabolic correction wave is independently generated by the DSP 110 and the D / A
After being converted into an analog signal by the converter 200, it is configured to be added to the analog output of the D / A converter 120 by the inverting adder 151. However, if a high-precision D / A converter 120 is used, the DSP1
Even if the parabolic correction is digitally performed at 10, the parabolic corrected data is sent to the D / A converter 120, and the parabolic corrected analog signal is directly output from the D / A converter 120. good.

Embodiment 2. FIG. 16 is a block diagram showing the configuration of a horizontal raster width digital control device according to another embodiment of the present invention. 16, parts that are the same as those in FIG. 1 are given the same reference numerals, and overlapping descriptions will be omitted. In the figure, 110a is a digital signal processor (hereinafter referred to as DSP) (digital signal processing means, correction wave generating means) that executes feedback control calculation of the horizontal raster width at the cycle of the horizontal synchronizing signal. Also, 201
Is a D / A converter that converts the digital parabolic correction wave output from the DSP 110a into an analog signal and supplies the analog signal to the input terminal of the adder 130. Note that the DSP
110a outputs a signal of the pulse cycle of the horizontal synchronizing signal H-SYNC as a sample hold pulse to the A / D converter 140.

Next, the operation will be described. FIG. 17 is a flow chart showing the horizontal raster width control operation of the horizontal raster width digital control apparatus according to the second embodiment. FIG.
The same steps are denoted by the same reference numerals, and overlapping description will be omitted. That is, in the first embodiment, step ST5
Although the presence or absence of the input of the vertical synchronizing signal V-SYNC is determined in 04 and ST508, in the second embodiment, the presence or absence of the input of the horizontal synchronizing signal H-SYNC is determined in steps ST504a and ST508a instead of these steps. There is.
That is, in the second embodiment, the subroutine SUB1 shown in FIG. 5 and the subroutine SUB2 shown in FIG. 6 are executed at the cycle of the horizontal synchronizing signal H-SYNC. However, in the second embodiment, concrete values of the coefficients K1 to K8 in the mathematical expressions (1) to (5) shown in the first embodiment are different.

Further, the digital parabolic correction wave output from the DSP 110a is converted into an analog signal by the D / A converter 201, and the D / A converter 12
The horizontal raster width signal H-SIZE _ref and the signal + B _ref output from 0 are input to the adder 130 and added. Therefore, in the feedback control, the parabola correction or the like for the pincushion distortion is performed for each horizontal line to control the horizontal raster width.

Embodiment 3 FIG. 18 is a block diagram showing the configuration of a horizontal raster width digital control device according to another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted. In the figure, 21
0 is a horizontal raster width control value output from the D / A converter 120, that is, a current controller (current control unit) that controls the amplitude of the base current of the horizontal output transistor 2 based on the combined value of the signals from the resistors 121, 122, and 123. Means), 2
Reference numeral 20 denotes a protection circuit (protection means, warning means) that monitors the horizontal raster width control value and performs processing such as turning off the power of the entire apparatus when an abnormality occurs.

Next, the operation will be described. The operation of digitally controlling the horizontal raster width and the operation of correcting the pincushion distortion and the like are the same as those in the first embodiment, and therefore description thereof will be omitted.

19 and 20 show the horizontal output transistor 2
6 is a graph showing changes in the horizontal raster width control value with respect to the operating time of the monitor device when the drive state is not optimally adjusted or when the drive state deviates from the optimal state due to aging. As shown in these figures, when the drive state of the horizontal output transistor 2 deviates from the optimum state, the horizontal raster width control value shows various changes depending on the situation. When the horizontal raster width control value changes in this way, the current control unit 210 controls the amplitude of the base current I _B input to the horizontal output transistor 2.

When the horizontal raster width control value changes as shown in FIGS. 19 and 20, the current controller 210 controls the amplitude of the base current of the horizontal output transistor 2 based on this change. That is, when the horizontal raster width control value increases, the base current of the horizontal output transistor 2 is reduced. FIG. 22 is a diagram showing changes in the amplitude of the base current of the horizontal output transistor 2 when the horizontal raster width control value increases. As shown in the figure, when the horizontal raster width control value increases, the amplitude of the base current shown by the dotted line becomes the amplitude of the base current shown by the solid line.

FIG. 21 is a graph showing a case where the horizontal raster width control value suddenly decreases due to a failure of the horizontal output transistor 2. As shown in the figure, when the horizontal raster width control value is not within the predetermined range, the monitor device is turned off. By doing this, accidents and disasters can be prevented. The protection circuit 2
The LED 20 may be made to blink in order to warn the user. Furthermore, the protection circuit 2 described above
Although 20 uses the horizontal raster width control value, it is also possible to use the horizontal raster width feedback value output from the differential amplifier 10. Further, in the third embodiment, the current control unit 210 and the protection circuit 220 are provided in the first embodiment which performs the feedback control for each cycle of the vertical synchronizing signal. However, as described in the second embodiment. The current control unit 210 and the protection circuit 220 can be similarly provided to the horizontal raster width digital control device of the second embodiment which executes the feedback control in the cycle of the horizontal synchronization signal.

[0081]

According to the first aspect of the invention, the digital signal processing means is provided with a difference signal between the signal output from the analog / digital signal converting means and indicating the desired horizontal width and the signal corresponding to the collector pulse voltage. The digital signal shown in the figure is input, feedback calculation processing is performed to control the horizontal width of the raster, and the digital signal of the calculation result is converted into an analog signal by the digital-analog conversion means. Since the deflection voltage is controlled, the horizontal width can be accurately controlled.

According to the invention of claim 2, the analog
Since the digital signal converting means is configured to sample and hold the analog output from the differential amplifying means at the timing of the vertical synchronizing signal, the horizontal width of the raster can be controlled without being affected by the raster distortion correction due to the vertical cycle. There is an effect that can be done.

According to the third aspect of the present invention, the raster width signal generation means is configured to generate the reference signal for horizontal raster width control based on the desired horizontal raster width input from the raster width input means. The horizontal raster width can be controlled based on the horizontal raster width desired by the user.

According to the fourth aspect of the invention, the digital signal processing means performs feedback calculation processing so that the output of the analog / digital signal conversion means becomes a predetermined converged digital value when the control of the feedback calculation processing converges. Since it is configured to execute, there is an effect that the horizontal width can be accurately controlled.

According to the fifth aspect of the present invention, the digital signal processing means executes the first feedback arithmetic processing having a high control speed a predetermined number of times immediately after the power is turned on or the horizontal synchronizing frequency is switched, and thereafter the control is performed. Since the second slow speed feedback calculation process is repeatedly executed, there is an effect that stable and accurate raster width control can be performed even in a transient state immediately after the power is turned on or the horizontal synchronizing frequency is switched.

According to the sixth aspect of the present invention, in the first feedback arithmetic processing of the digital signal processing means, the value of the digital signal output from the analog / digital signal converting means is converted into a plurality of regions with the converged digital value as a reference. Since it is configured to perform feedback calculation processing with different control speeds for each area, stable and accurate raster width control can be performed even in a transient state immediately after power is turned on or horizontal sync frequency is switched. There is an effect that can be done.

According to the seventh aspect of the invention, the correction wave generating means generates a correction wave for correcting the horizontal width of the raster at the cycle of the vertical synchronizing signal, and the correction wave is digital / analog by the signal adding means. Since it is configured to be added to the analog signal output from the converting means, there is an effect that the horizontal width of the raster can be corrected at the cycle of the vertical synchronizing signal without affecting the feedback control of the horizontal width of the raster.

According to the eighth aspect of the present invention, the correction wave generation means stops the generation of the correction wave in the correction wave generation means immediately after switching the horizontal synchronizing frequency, and the voltage value output from the horizontal deflection voltage control means is Since it is configured to output a signal of a predetermined voltage from the correction wave generation means so as to be low,
There is an effect that the control of the raster width is prevented from becoming unstable immediately after the switching of the horizontal synchronizing frequency, and the stress applied to the horizontal output transistor can be reduced.

According to the ninth aspect of the invention, the digital signal processing means digitally adjusts the voltage value output from the horizontal deflection voltage control means to be low for a predetermined period immediately after the power is turned on or the horizontal synchronizing frequency is switched. Since it is configured to send digital data to the analog signal conversion means, it is possible to prevent the control of the raster width from becoming unstable immediately after the power is turned on or the horizontal synchronizing frequency is switched,
This has the effect of reducing the stress on the horizontal output transistor.

According to the tenth aspect of the present invention, the feedback calculation process of the digital signal processing means includes the horizontal synchronizing signal frequency as a parameter, and is configured to absorb the control fluctuation due to the difference in the horizontal synchronizing signal frequency.
Even if the horizontal synchronizing signal frequency is changed, the raster width can be stably and accurately controlled.

According to the eleventh aspect of the present invention, the digital signal processing means executes the feedback calculation processing by using the digital data converted and output from the analog / digital signal converting means one cycle before the vertical synchronizing signal. With this configuration, it is possible to use an analog / digital signal converting means having a low speed, and it is possible to reduce the cost.

According to the twelfth aspect of the present invention, the analog / digital signal converting means samples and holds the analog output from the differential amplifying means with a delay of half the vertical synchronizing signal period from the timing of the vertical synchronizing signal. With this configuration, the raster width can be controlled while keeping the horizontal width of the central portion of the raster constant.

According to the thirteenth aspect of the present invention, the analog / digital signal converting means is configured to sample and hold the analog output from the differential amplifying means at the timing of the horizontal synchronizing signal. There is an effect that the horizontal raster width can be finely controlled in the cycle.

According to the fourteenth aspect of the present invention, the correction wave for correcting the horizontal width of the raster is added in the cycle of the vertical synchronizing signal and the second signal is added, and the added signal is output to the differential amplifying means. With this configuration, it is possible to accurately control the raster width for each raster line.

According to the fifteenth aspect of the present invention, the amplitude of the base current of the horizontal output transistor is controlled based on the change of the analog signal output from the digital-analog conversion means. Even if the drive state of the horizontal output transistor changes, there is an effect that it can be corrected to an appropriate state.

According to the sixteenth aspect of the present invention, when the analog signal output from the digital-analog converting means is not within the predetermined range, it is judged as abnormal and the power supply of the horizontal raster width digital control device is turned off. With this configuration, when a horizontal output transistor or the like fails, it is possible to prevent a fire or the like due to the failure from occurring.

According to the seventeenth aspect of the invention, when the value of the analog signal output from the digital-analog converting means is not within the predetermined range, it is judged as abnormal and a warning is given to the user. Therefore, when a horizontal output transistor or the like fails, a fire or the like due to the failure can be prevented.

According to the eighteenth aspect of the present invention, when the value of the output from the differential amplifying means is not within the predetermined range, it is judged as abnormal and the power supply of the horizontal raster width digital control device is turned off. Since it is configured, when a horizontal output transistor or the like fails, there is an effect that fire or the like due to the failure can be prevented.

According to the nineteenth aspect of the present invention, when the value of the output from the differential amplifying means is not within the predetermined range, it is judged as abnormal and a warning is given to the user. When the output transistor or the like fails, there is an effect that fire or the like due to the failure can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a horizontal raster width digital control device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a signal + B _ref indicating a voltage value of an output voltage + B of a horizontal deflection voltage and a horizontal synchronizing signal f _H.

FIG. 3 is a graph showing a relationship between a voltage + B and a horizontal synchronizing frequency f _H when a horizontal raster width H-SIZE desired by a user is a median value.

FIG. 4 is a horizontal raster width H-SIZE desired by a user.
Is a graph showing the relationship between the voltage + B and the horizontal synchronization frequency f _H for each of the minimum value, the median value, and the maximum value.

FIG. 5 is a flowchart showing a main routine of a horizontal raster width control algorithm in the DSP.

FIG. 6 is a flowchart showing a subroutine SUB1 of horizontal raster width control in a transient state.

FIG. 7 is a flowchart showing a subroutine SUB2 of horizontal raster width control in a steady state.

FIG. 8 is a circuit diagram showing a comparator and a horizontal deflection voltage control circuit.

FIG. 9 is a waveform diagram showing a waveform of an input / output signal of a comparator in a constant state.

FIG. 10 is a waveform diagram showing the waveform of the input / output signal of the comparator immediately after the power is turned on.

FIG. 11 is a graph showing the relationship between the output voltage of the D / A converter and the horizontal synchronizing frequency.

FIG. 12 is a diagram showing a horizontal deflection voltage, a voltage of a horizontal deflection circuit unit output terminal, a vertical synchronization signal, and a sample hold pulse of an A / D converter when the pincushion distortion correction is performed.

FIG. 13 is a diagram showing a raster and a situation of pincushion distortion correction when the A / D converter is sampled and held at the timing of the vertical synchronizing signal.

FIG. 14 is a diagram showing a situation of raster and pincushion distortion correction when the A / D converter is sampled and held at a timing delayed by a half cycle from the vertical synchronization signal.

FIG. 15 is a graph showing a parabolic correction wave output from a DSP and a voltage output when switching frequencies.

FIG. 16 is a block diagram showing a configuration of a horizontal raster width digital control device according to a second embodiment of the present invention.

FIG. 17 is a flowchart showing a horizontal raster width control operation of the horizontal raster width digital control device according to the second embodiment.

FIG. 18 is a block diagram showing a configuration of a horizontal raster width digital control device according to the third embodiment.

FIG. 19 is a graph showing changes in the horizontal raster width control value with respect to the operating time of the monitor device when the drive state of the horizontal output transistor is not optimally adjusted or when the drive state deviates from the optimum state due to aging. It is a figure.

FIG. 20 is a graph showing changes in the horizontal raster width control value with respect to the operating time of the monitor device when the drive state of the horizontal output transistor is not optimally adjusted or when the drive state deviates from the optimum state due to aging. It is a figure.

FIG. 21 is a graph showing a case where the horizontal raster width control value suddenly becomes small, such as when the horizontal output transistor fails.

FIG. 22 is a diagram showing changes in the amplitude of the base current of the horizontal output transistor when the horizontal raster width control value is increased.

FIG. 23 is a block diagram showing a configuration of a conventional analog horizontal raster width digital control device.

FIG. 24 is a block diagram showing a configuration of a conventional display device which controls by converting a raster width into a digital signal.

FIG. 25 is a diagram showing signal waveforms at various parts of the conventional display device shown in FIG. 24.

[Explanation of symbols]

1 Horizontal output choke transformer (voltage measuring means) 2
Horizontal output transistor, 4 deflection yokes, 7A, 7B
Diode (voltage measuring means), 8 capacitor (voltage measuring means), 10 differential amplifier (differential amplifying means), 11
Horizontal deflection voltage control device (horizontal deflection voltage control means), 10
0 CPU (raster width input means), 101 rotary encoder (raster width input means), 110, 110a
DSP (digital signal processing means, correction wave generation means),
120 D / A converter (digital / analog signal conversion means, raster width signal generation means), 130 adder (raster width signal generation means), 140 A / D converter (analog / digital signal conversion means), 151 inverting adder ( Signal adding means), 152 comparator (voltage control signal generating means), 210 current control section (current control means),
220 Protection circuit (protection means, warning means).

Claims (19)

[Claims] 1. A horizontal raster display width control device for controlling a horizontal display width of a raster displayed on a cathode ray tube, and a deflection yoke for horizontally deflecting an electron beam of the cathode ray tube, and an input control signal. And a horizontal deflection voltage control means for controlling and outputting a power supply voltage for applying a voltage to the deflection yoke based on the above, and a voltage based on the power supply voltage output from the horizontal deflection voltage control means for timing of a horizontal synchronizing signal. Shows a horizontal output transistor applied to the deflection yoke, a voltage measuring means for measuring and outputting a first signal corresponding to a collector pulse voltage of the horizontal output transistor, and showing the first signal and a desired horizontal width. A differential amplifier that outputs a difference signal from the second signal, and an analog / digital signal converter that converts the output from the differential amplifier into a digital signal. And a digital signal processing means for inputting the digital signal output from the analog / digital signal converting means, performing feedback arithmetic processing for controlling the horizontal width of the raster, and outputting a digital signal of the arithmetic result. A digital / analog conversion means for converting a digital signal output from the digital signal processing means into an analog signal, and a control signal for controlling the power supply voltage based on the analog signal output from the digital / analog conversion means. A horizontal raster width digital control device, comprising: a voltage control signal generation means for generating and outputting to the horizontal deflection voltage control means. 2. The horizontal raster width digital control apparatus according to claim 1, wherein the analog / digital signal converting means samples and holds the analog output from the differential amplifying means at the timing of the vertical synchronizing signal. 3. A raster width input means for inputting a desired horizontal raster width and a raster width signal generating means for generating a second signal based on the desired horizontal raster width input by the raster width input means. The horizontal raster width digital control device according to claim 1 or 2, further comprising: 4. The feedback calculation process according to claim 1, wherein the feedback calculation process is executed so that the output of the analog / digital signal conversion unit becomes a predetermined converged digital value when the control of the feedback calculation process of the digital signal processing unit converges. 4. The horizontal raster width digital control device according to claim 3. 5. The digital signal processing means executes a first feedback calculation process having a fast control speed a predetermined number of times immediately after the power is turned on or the horizontal synchronizing frequency is switched, and thereafter a second feedback calculation process having a slow control speed. The process according to claim 4, wherein the process is repeatedly executed.
A horizontal raster width digital controller as described. 6. In the first feedback arithmetic processing of the digital signal processing means, the value of the digital signal output from the analog / digital signal converting means is divided into a plurality of areas with the converged digital value as a reference, and each area is divided. 6. The horizontal raster width digital control device according to claim 5, wherein feedback calculation processing with different control speeds is performed for each. 7. A correction wave generation means for generating a correction wave for correcting the horizontal width of a raster in a cycle of a vertical synchronization signal, and a signal for adding the correction wave to an analog signal output from a digital / analog conversion means. And a voltage control signal generation means for generating a control signal for controlling the power supply voltage based on the signal output from the signal addition means and outputting the control signal to the horizontal deflection voltage control means. The horizontal raster width digital control device according to any one of claims 1 to 6. 8. The correction wave generation means stops the generation of the correction wave immediately after the switching of the horizontal synchronization frequency, and a predetermined voltage is output from the correction wave generation means so that the voltage value output from the horizontal deflection voltage control means becomes low. 8. The horizontal raster width digital control device according to claim 7, which outputs the signal of FIG. 9. The digital signal processing means applies digital data to the digital / analog signal conversion means so that the voltage value output from the horizontal deflection voltage control means becomes low for a predetermined period immediately after the power is turned on or the horizontal synchronizing frequency is switched. Is sent out.
A horizontal raster width digital controller according to any one of the above. 10. The feedback calculation process of the digital signal processing means includes the horizontal synchronizing signal frequency as a parameter so as to absorb the control fluctuation due to the difference of the horizontal synchronizing signal frequency. 5. A horizontal raster width digital control device according to any one of 1 above. 11. The digital signal processing means is analog
3. The feedback calculation process is executed by using the digital data converted and output from the digital signal converting means one cycle before the vertical synchronizing signal.
A horizontal raster width digital controller as described. 12. The analog-to-digital signal converting means samples and holds the analog output from the differential amplifying means with a delay of half the vertical synchronizing signal cycle from the timing of the vertical synchronizing signal. A horizontal raster width digital controller as described. 13. The horizontal raster width digital control apparatus according to claim 1, wherein the analog / digital signal converting means samples and holds the analog output from the differential amplifying means at the timing of the horizontal synchronizing signal. 14. A correction wave generation means for generating a correction wave for correcting the horizontal width of the raster at the cycle of the vertical synchronizing signal,
14. The horizontal raster width digital control device according to claim 13, further comprising: an addition unit that adds the correction wave and the second signal and outputs the added signal to a differential amplification unit. 15. The method according to claim 1, further comprising current control means for controlling the amplitude of the base current of the horizontal output transistor based on a change in the analog signal output from the digital-analog conversion means. 2. A horizontal raster width digital controller according to item 1. 16. A protection means for turning off the power supply of the horizontal raster width digital control device when the analog signal outputted from the digital-analog conversion means is not within a predetermined range and is judged to be abnormal. 16. The horizontal raster width digital controller according to claim 15. 17. The method according to claim 1, further comprising warning means for judging an abnormality and warning the user when the value of the analog signal output from the digital-analog conversion means is not within a predetermined range. 17. A horizontal raster width digital controller according to any one of 16. 18. The method according to claim 1, further comprising a protection means for turning off the power supply of the horizontal raster width digital control device when the output of the differential amplification means is not within a predetermined range, which is judged as an abnormality. 16. A horizontal raster width digital controller according to any one of paragraphs 15. 19. The method according to claim 1, further comprising warning means for judging an abnormality and warning the user when the value of the output from the differential amplifying means is not within a predetermined range. 19. A horizontal raster width digital controller according to any one of 18.