KR820000861B1 - Set-up arrangement for color television receiver - Google Patents

Abstract

The color temperature adjustment circuit for television CRT's provides compensation for variations between the electron guns, and between the efficiency of the various screen phosphors. Adjustment is achieved by processing in individual channels the color, brilliance and synchronisation signals. Each such channel has a two position switch, one position being for normal receiver operation and the second selectively rendering inoperative the colour and brilliance channels. A second video circuit operates independently of the normal synchronisation signal separation circuit (60), the output of this second channel feeding a synchronisation signal generator (62).

Description

Color TV receiver

1A and 1B are a partial schematic and schematic circuit diagram of a general configuration of a color television receiver using the apparatus constructed by the present invention, respectively.

2 is a variant of the device shown in FIGS. 1a and 1b.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to color televisions, and more particularly, to an apparatus for facilitating adjustment and service of a color kinescope used in a color television receiver.

The adjustment of the color kinescope involves the adjustment of the color temperature and many other adjustments. When adjusting the color temperature, it is also necessary to consider the difference in cathode emission of the kinescope-specific electron beam generating electron gun or the difference in the phosphor efficiency of the kinescope. In general, the color temperature is adjusted by adjusting the DC control voltage applied between the cathode of the kinescope and the grid, and white information is reproduced at an appropriate color temperature at all brightness levels between the minimum and maximum, so that the image of the maximum white level is a good intelligibility. The AC gain adjustment of the drive of the kinescope should be made to produce at the highest brightness level achievable.

It is well known that among a Karakel vision receiver, a service switch device which is a convenient means for a worker to perform adjustment without using a special device in a factory is installed. In general, switch devices for service are kept in "normal" and "service" positions. When the service switch device is set to the "normal" position, the video signal is supplied to the kinescope so that the receiver reproduces the normal video.

When the service switch device is set to the "service" position, the vertical deflection circuit stops operation, and since the chromaticity signal and the luminance signal are not supplied to the kinescope, the kinescope is in a static operation state. The DC control signal supplied to the grid (or cathode) of each electron gun is gradually controlled until the horizontal line is barely visible on the kinescope by the electron gun.

When viewed from a reasonable distance where all three sets of electron guns work in this way, one set of white lines of low luminance level appears.

Several service switch devices

United States Patent No. 3114796 (granted to J. Stararch II, etc.),

U.S. Patent No. 3270125 (G. E. Kelly et al.),

U.S. Patent No. 3412,525 (permitted to P. E. Cronkshank, etc.),

U.S. Pat.No.3525801 to D. H. Willis,

U.S. Patent No. 3820155 to D. L, Niall, and

US Patent No. 3959811, issued to R. L. Sanlay II.

When drawing one or more unstable or partially stabilized operating voltages for a color television receiver from the horizontal output circuit of the horizontal deflection stage of the receiver, special problems arise in making correct adjustments. In most cases, such a voltage is finally generated from the oscillation output signal of the horizontal oscillator in the horizontal deflection stage. The magnitude of this voltage is partly determined by the oscillation frequency of the horizontal oscillator. On the other hand, this oscillation frequency is stabilized by a synchronization signal drawn from the received synthesized video signal.

In the absence of the synchronization signal, the oscillation frequency is changed because it is not stabilized, and thus the drawn receiver operating voltage also changes.

In the service or coordination operation mode of such a television receiver, it is desirable to give a accurately simulated static operation state in order to adjust the color television receiver accurately and easily. Furthermore, in order to minimize other problems caused by picking up stray signals and coupling AC signals to long conductors, it is desirable to control each part of the receiver in a service switch that combines DC control signals rather than AC control signals. Do.

Another problem arises when designing a "service" adjustment circuit for color temperature adjustment of a receiver of a type having an auxiliary return circuit. During the vertical retrace-horizontal edge, such circuits, which operate to prohibit the operation of the kinescope and prohibit the display of annoying horizontal edgelines, are granted to Mr. Willis and have been transferred to the R.A. Corporation as described herein. It is described in the specification of patent 3,984,864.

In the case of adopting such a configuration, it is necessary to be sufficiently prepared that the auxiliary retracement does not adversely affect the adjustment work.

According to the present invention, a control device is provided in an apparatus for processing a composite color video signal containing a chroma signal component, a luminance signal component, and a synchronization signal component. The apparatus of the present invention includes a chromaticity channel and a luminance channel for processing chromaticity components and luminance components. In addition, a color image reproducing apparatus is provided with a plurality of color generating electron beam apparatuses in response to chromaticity and luminance signals supplied through the chromaticity channel and the luminance channel. Moreover, it has a deflection circuit related to the electron beam apparatus for performing horizontal and vertical scanning of the reproducing apparatus.

The deflection circuit is provided with a means for generating a periodic signal by maintaining a frequency synchronized with a supplied synchronous input signal with a time interval representing a sweep line and a retrace period of the image. The operating voltage of the receiver having a magnitude dependent on the frequency of the periodic signal is generated from the periodic signal. In addition, a switch is coupled to each of the DC voltage control terminals of the chromaticity and luminance channels and the deflection circuit. In the first position of the switch, both the chromaticity and luminance channels and the deflection circuits operate in the normal operating mode of the device. When the switch is in the second position, the chromaticity and luminance channels do not supply chromaticity and luminance components, and the deflection circuit stops scanning in one direction of the image reproducing apparatus. Thereby, the device can be adjusted in the service operation mode. A signal separator, operating separately from the chromaticity and luminance channels, separates the synchronous components from the composite video signal. The combining circuit supplies this separated synchronization signal component to the synchronization signal input to the periodic signal extraction device regardless of the position of the switch. The operating voltages of the receivers thus drawn are substantially the same during the periods of both the normal mode and the service mode.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1A and 1B are provided with a video processing apparatus 12 for receiving a radio frequency (RF) signal from the antenna 10 and converting the signal into a composite video signal through an intermediate frequency (IF) amplification and detection unit (not shown). One color television receiver is shown. The synthesized video signal is composed of a chroma signal component, a luminance signal component, and a synchronization signal component.

The frequency selector 13 selectively supplies the chromaticity components to the chromaticity channel 14. Chromaticity channel 14 has a chromaticity processing circuit 16 and processes chromaticity components to extract R-Y, B-Y and G-Y color difference signals. The signal gain of the chromaticity processing circuit 16 is adjusted by the color control potentiometer 90 that the viewer can adjust, thereby adjusting the amplitude of the signal processed by the circuit 16. The color difference signals are supplied to respective inputs of the kinescope driving stages 18a, 18b, and 18c of the kinescope driving apparatus 20, respectively. The kinesque driving stage synthesizes the color difference signals of R-Y, B-Y and G-Y with the luminance output signal Y of the luminance channel 22 to generate the color signals of R, B and G.

Each color signal of R, B and G is supplied to the cathodes of three sets of electron guns of kinescope 38, respectively. For example, each electron gun consisting of a cathode, a control grid, and a shield grid generates an electron beam to accelerate them. The kinescope is also equipped with focusing and alternating electrodes. The control grid is supplied with a DC bias control voltage from the bias control circuit 40, and the shielding grid is supplied with a DC shielding control voltage from the shielding control circuit 42 to adjust the breaking point of each electron gun.

As the illustrated kinescope driving stages 18a, 18b and 18c, those shown in the specification of US Pat. No. 3,970,895 to Mr. Willis may be used. However, 18a, 18b and 18c have the same structure, so the detailed description of this 18c is equally applicable to 18a and 18b.

18c is composed of NPN amplified transistor 24C and NPN keyed clamp transistor 26c connected in a feedback manner as shown. The operating voltage is supplied to only 18c from a + 210V supply.

The RY color difference signal is supplied to the base electrode of the transistor 24c through the coupling capacitor 34c, and the luminance output signal Y portion from the luminance channel 22 is supplied to the emitter electrode of the transistor 24c through the variable drive control resistor 28c and from the key stage 130. The periodic keying signal is supplied to the emitter of transistor 26c. The luminance signal and the keying signal are also simultaneously supplied to corresponding inputs of the driving stages 18a and 18b.

The transistor 24c synthesizes and amplifies the Y signal and the R-Y signal, and generates a color signal R at its collector output. Variable resistor 28c may adjust the gain of only 18c. The capacitor 34c and the transistor 26c constitute a key clamp circuit, and the voltage generated in the emitter of the transistor 24c is substantially constant and the direct current condition of the color processing circuit 16 and the base of the transistor 24c. Keep the emitter voltage independent of fluctuations. The clamping operation is performed when the transistor 26c is brought into a conductive state in response to the keying pulse generated by the keying circuit 130 during the horizontal flyback period.

The output of the video processing apparatus 12 is also supplied to the synchronous separator 60, and a positive periodic agitator pulse is drawn from the video signal irrelevant to the operation of the chromaticity and luminance channels.

The extracted sync pulses correspond to those in phase with the synchronous components in the video signal, which are supplied to the horizontal deflection stage including the horizontal oscillator 62 and the horizontal signal processing circuit 64 via the conductor 66. A vertical deflection stage including a vertical signal processing circuit 74 is supplied.

The periodic vertical deflection and vertical blanking cancellation signals generated by the vertical signal processing circuit 74 are supplied to the 38 vertical deflection windings and the luminance channel 22 of the kinescope, respectively. The output signal of the horizontal signal processing circuit 64 is supplied to the horizontal flyback transformer 76 to extract the horizontal blanking clear signal, the horizontal deflection signal, and the horizontal flyback signal. The horizontal deflection signal is supplied to the horizontal deflection winding of the kinescope 38, and the horizontal blanking cancellation signal is supplied to the luminance channel 22.

The positive horizontal flyback signal generated during the horizontal synchronization period of the video signal, i.e., the retrace period, is supplied to the high voltage circuit (e.g., the tripled circuit) 78, and the high operating voltage supplied to the alternating electrode and the focusing electrode of the kinescope 38. Is generated. The horizontal flyback signal is also supplied to 130 to the keying circuit of luminance channel 22.

In response to the horizontal flyback signal in the negative direction, the keying circuit 130 substantially coincides with this signal to generate a periodic keying signal in the negative direction during the horizontal retrace period. As shown in the specification of US Pat. No. 3,970,895, the keying signal controls the operation of the keyed bias transistor (e.g., 26c) of the kinescope drive stage during the horizontal retrace period.

The horizontal flyback transformer 76 is also rectified to generate an unstabilized DC receiver operating voltage. For example, the unstabilized operating voltage (+210 V) for the drive stage of the kinescope is generated from the voltage generated in the tapped secondary winding of the horizontal flyback transformer 76.

The luminance channel 22 includes the luminance signal processing circuit 44 and amplifies the luminance component of the synthesized video signal. In other cases, the luminance channel 22 is processed to generate a luminance output signal of, for example, "polarity of the sync tip". The luminance component generated at the output of the circuit 44 includes a signal component indicating some video information between the blanking pulse and the blanking pulse therefrom.

The luminance component generated at the output of the circuit 44 is supplied to the keyed blanking level clamp circuit of the coupling capacitor 104 and the PNP clamp transistor 110. The periodic keying signal from the keying circuit 130 is combined with the synchronizing signal from the synchronizing separator 60 in the base electrode of the transistor 110 to generate a switching signal for controlling the clamp (conduction) period of the clamp transistor 110. The clamp transistor 110 conducts periodically and clamps the luminance signal in response to the lowest amplitude level of the switching signal. When the clamp transistor 110 is turned on, the luminance signal supplied through the capacitor 104 is clamped to the voltage generated at the base of the transistor 110. This voltage represents the blanking reference level corresponding to the hog tone of the image.

Positive periodic horizontal and vertical retrace pulses are synthesized by the retrace circuit 160 and subjected to amplitude limitations, with time intervals corresponding to the horizontal and vertical retrace periods, respectively.

The synthesized blanking signal is supplied to the base electrode of the PNP luminance amplifying transistor 105, where the synthesized blanking signal is added to the clamped luminance signal so that the kinescope 38 is virtually blocked during the horizontal and vertical return periods. The transistor 105 supplies the amplified and clamped luminance signal Y to the kinescope drive stages 18a, 18b, and 18c.

The output of the keying circuit 130 is also supplied to the auxiliary retrace clear circuit 145 to generate an auxiliary, preliminary periodic retracting pulse during each vertical retrace-horizontal draw period, and during this period, the kinescope 38 is switched off. Avoid distracting horizontal line marks. As the keying circuit 130 and the auxiliary retrace elimination circuit 145, ones of the same type as described in the specification of US Patent No. 3,984, 864 may be used.

The clamp transistor 110 is further controlled by the variable resistor 112 for brightness control. The variable resistor 112 may be manually adjusted by the viewer to change the conduction of the clamp transistor 110 to obtain the desired image luminance level.

In short, for example, the variable resistor 112 operates to adjust the bias of the key clamp transistor 110, thereby adjusting the conduction and clamp voltage levels of the transistor 110. By adjusting the resistor 112 between the minimum (MIN) and the maximum (MAX) portions, the blanking level (i.e. black) level of the luminance signal is changed, whereby the luminance of the image can be adjusted from the minimum level to the maximum level. . As the lightness control device including the circuit portion shown in its entirety at 100, those described in detail in US Patent No. 4,044,375 to Norman may be used.

The two-position service switch 82 with two electrically isolated poles and the "normal" and "service" positions makes it easy to perform initial adjustment of the receiver's operating state. The water receiver typically operates in the "normal" position. When the service switch 82 is in the "service" position, the color temperature of the kinescope 38 can be adjusted. The poles of Article 1 include poles 84a, 86a and 88a. The pole 84a is directly connected to the lower terminal of the brightness regulating resistor 112, connected to the lower side of the chromaticity control potentiometer 90 through the resistor 93, and coupled to the static DC voltage source (+ 22V) via the resistor 92. Pole 86a is connected to a reference potential point (e.g., ground) and pole 88a is coupled to the control input of the auxiliary retrace clear circuit 145.

The poles of Article 2 include their 84b, 86b and 88b. In this embodiment, the pole 84b is not connected anywhere. Pole 86b is coupled to the non-DC voltage source (-40V), and pole 88b is coupled to the control input of the vertical oscillator 72.

In the "normal" position, poles 84a and 86a are connected to each other by negligible impedance, whereby the connection point of pole 84a, and therefore resistors 92 and 93, is the ground potential. The chromaticity control potentiometer 90 and the brightness control resistor 112 operate in a normal state and the chromaticity and luminance signals as described above are normally processed by the chromaticity and luminance channels.

In the "service" position, poles 86b and 88b are connected to each other by negligible impedance, whereby negative voltage (-40V) is generated at pole 88b, which is supplied to the control input of the vertical oscillator 72. The negative voltage stops the operation of the vertical oscillator 72, thereby stopping the vertical scanning of the kinescope 38. As a result, the displayed image is depressed by being pushed in the vertical direction to form a narrow set of parallel lines in the center of the display screen of the kinescope. Also in the "service" position, pole 84a is isolated from ground, and the voltage at the junction of resistors 92 and 93 rises. As a result, a DC voltage is generated between both ends of the chromaticity control potentiometer 90, and the voltage generated at the wiper of the potentiometer 90 is + 11.2V and + 22V, and the voltage of the + 11.2V and + 22V resistors is divided by the resistance of the potentiometer 90. It will be over 11.2V This elevated positive DC voltage decreases the gain of the chromaticity processing circuit 16 (i.e., bias-off), whereby virtually no chromaticity signal supplied through the chromaticity processing circuit 16 is removed from the chromaticity channel.

Definition DC low voltage occurs across the brightness control resistor 112 as a result of the voltage dividing action by the resistor 112, the resistor 92 and the voltage source of + 22V. The elevated constant voltage generated on the wiper of the variable resistor 112 further raises the base voltage of the transistor 110 to a positive level so as to correspond to the returning level of "black than black". Accordingly, the elevated constant voltage is generated at the connection point of the capacitor 104 and the emitter of the transistor 110 during the clamping period of the transistor 110, and operates to reverse bias the luminance amplification transistor 105. The luminance signal is insufficient to bring the forward biased transistor 105 to conduction during this time, and no current flows substantially in the emitter of the transistor 105.

Since the luminance and chromatic channels cannot supply luminance signal components and chromatic signal components to the kinescope 38 in this "service" mode, the amplifying transistors (e.g. 24c) of the kinescope drive stage are each negative electrode of the kinescope 38. It operates to supply a static DC voltage which is almost equal to the DC voltage supplied when there is no luminance and chroma signal. In this state, the color temperature of the kinescope can be adjusted by adjusting the fixed voltage supplied from the shielding control circuit 42 to the kinescope 38 so that each electron gun is at the threshold level between conduction and shielding.

Moreover, in this "service" position, poles 86a and 88a are connected to each other with negligible impedance, whereby pole 8a is connected to ground. The ground voltage coupled to the control input of the auxiliary retrace clear circuit 145 in 88a inhibits the operation of the circuit 145, thereby removing the auxiliary retrace pulse from the drive stage of the kinescope. If the auxiliary retrace pulse is not removed, the static operation state of the kinescope drive stage is confused, thereby causing the color temperature adjustment state of the kinescope 38 to be confused. If no auxiliary retrace pulse is present, the connection from the pole 88a to the auxiliary retrace clear circuit 145 is not necessary.

The latter connection combines only the AC signal with the switch 82, and the other connection combines the DC signal. Thus, according to the circuits of FIGS. 1A and 1B, other problems such as pick-up of noise and capacitive load, which sometimes occur when a long connection is used to supply an AC signal to the service switch, are significantly reduced.

In the " service " mode, the video processing device 12 does not stop operation, so the device 12 continues to supply a composite video signal including luminance, chromaticity and synchronization components.

At this time, the chromaticity and components normally supplied through the chromaticity and luminance channels are prevented from reaching the kinescope as described above. In addition, since the frequency synchronous component is supplied to the oscillator 62 irrespective of the position of the switch 82, the horizontal oscillator 62 responds to the frequency equalizer component supplied by the synchronous separator 60 at a substantially constant desired horizontal frequency (for example, 15,734 kHz). It works.

The frequency of the oscillation output signal of the horizontal oscillator 62 is changed when there is no synchronous component (for example, when the video 1F stage of the video processing device 12 does not operate), for example, by a pseudo signal such as temperature change or noise. Slightly changed. This causes an undesirable phenomenon in which the operating static pressure of the unstabilized water receiver drawn out from the horizontal flyback transformer 76 fluctuates in response to the horizontal output signal coupled to the transformer 76. Such an operating voltage for the receiver may include, for example, an + 210V operating voltage as shown, an operating voltage related to the shield grid of the kinescope 38, and the like.

The + 210V operating static pressure for kinescope drive stages 18a, 18b and 18c consists of a positive flyback pulse (e.g., maintaining a peak value of + 210V) that occurs periodically in line with the horizontal retrace period, for example. The voltage waveform generated in the secondary winding of the transformer is generated by drawing out the rectifier 79 and the filter capacitor 80.

In the absence of the synchronous component, if there is a variation in the frequency of the output of the horizontal oscillator, a variation corresponding to the timing of the positive pulse voltage drawn from the secondary winding 76 of the transformer 76 occurs. If there is an increase or decrease in the signal frequency of the horizontal oscillator, a corresponding decrease or increase in the width of the signal sweep line period associated with the return period (in this example, the return period is kept substantially constant). The magnitude of the average DC voltage rectified by the diode 79 and obtained by the capacitor 80 becomes a coefficient of the positive duty cycle of each retrace period, and correspondingly, the + 210V operating voltage rises or falls.

Further, as a specific example, when the frequency of the output signal of the horizontal oscillator decreases, the sweep line period of the constant level voltage waveform increases with respect to the retrace period, and the average constant DC level of the constant duty cycle, that is, the constant pulse voltage waveform, decreases. . For this reason, the rectified rectifier voltage falls slightly below a predetermined 210V. If there is a frequency variation of ± 500Hz, the desired + 210V voltage changes by 10 to 15V.

In essence, the desired level of the unstabilized operating voltage drawn in this way depends on the operation of the horizontal oscillator 62 at the appropriate frequency. For example, if the horizontal oscillator 62 is not synchronized by the synchronous component during the service mode, when the oscillation frequency changes, the operating voltage source (+ 210V) for the drive stage of the kinescope changes. If the operating frequency of oscillator 62 is properly set (synchronized) in response to the synchronous component, in the "normal" mode, the kinescope's driving stage operating voltage returns to normal, so the adjustment of the kinescope executed under the above conditions is incorrect. Done.

In the apparatus according to the invention of the type described above, by responding to the synchronous component the horizontal oscillator 62 during the "service" mode, the normal static operating state of the receiver can be accurately simulated and the kinescope can be adjusted accurately and easily.

Referring to FIG. 2, there is shown a simpler and more economical service switch 282 with a "normal" position and a "service" position.

Switch 282 has three poles 283,285 and 287. Pole 283 is coupled to the control input of vertical oscillator 72 (FIG. 1B) and pole 285 is coupled to a non-DC voltage source (-40V). Pole 287 is connected to the connection points of resistors 92 and 93 (Fig. 1b) and also includes a series resistors 295, 2962 and 297 connected between a direct current voltage source (+210 V) and a non-DC voltage source (-40 V). It is also coupled to the point. The connection points of resistors 296 and 297 are coupled to the control grid of kinescope 38.

In the "normal" position, the receiver and the luminance and chromaticity control circuits all operate normally as described above.

However, in the configuration of FIG. 2, the luminance and chromaticity control circuit is biased with respect to a voltage source of -40V via poles 285 and 287 coupled to the connection points of resistors 92 and 93 in FIG. In comparison, in the circuit of FIG. 1B with the service switch 82, the connection points of resistors 92 and 93 are coupled to ground potential through poles 81a and 86a when the service switch 82 is in the “normal” position. Therefore, according to the configuration of FIG. 2, it is necessary to select the values of the resistors 92 and 93 so that the brightness control potentiometer 112 chromaticity control potentiometer 90 can perform a predetermined amount of control in the normal operation mode.

In addition, in the normal mode, a first voltage is generated at the connection points of the resistors 296 and 297 to bias the control electrode of the kinescope 38. When the service switch 282 is in the "service" position, a negative DC voltage source (-40V) is coupled to the control input of the vertical oscillator 72 (FIG. 1B) via a negligible impedance from pole 285 and pole 283, as described above. Vertical scanning stops. At this time, the control grid electrode bias voltage of the raised kinescope appears at the connection points of the resistors 296 and 297. This control grid bias voltage is in the direction of bringing the kinescope 38 to conduction (i.e., turn) or close to conduction. At this time, the kinescope is adjusted by adjusting the voltage supplied to the kinescope 38 by the shielding control circuit 42. When the service switch 282 returns to the "normal" position, the bias voltage of the control grid returns to the original bias voltage.

Although the present invention has been described by specific embodiments, it goes without saying that various modifications other than the above-described embodiments are included within the scope of the present invention.

Claims (1)

A color television receiver for processing a composite color video signal including luminance, chromaticity and registered signal components, comprising: a luminance channel 22, a chroma channel 14, a color image reproducing apparatus 38, and a vertical signal processing circuit ( 74, a deflection device including a horizontal oscillator 62 and a horizontal signal processing circuit 64 for generating a periodic signal having a frequency synchronized by the synchronization signal input, and a synchronization separator 60 for separating the synchronization signal components. And a device (76) for generating an operating voltage for a receiver having a magnitude dependent on the frequency thereof from a periodic signal, the color television receiver having a first normal operating position and a second service operating position. Switching devices 82 and 282 capable of adjusting the color image reproducing device 38 in a service operation mode, and a synchronization signal component coupled to the sync separator 60 to be separated regardless of the position of the switching device. Adjusting device for a color television receiver, characterized in that a device (66) is supplied to the horizontal oscillator (62) as a synchronization signal input.

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