JPS6211833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a PLL circuit to which an index signal from a beam index type color picture tube is supplied, and based on the output signal of this PLL circuit, the output of the beam index type color picture tube is determined. Regarding beam index type color television receivers configured to perform color switching, in particular, the ability of the PLL circuit to follow fluctuations in the high voltage supplied to the beam index type color picture tube has been improved to ensure good color quality. This allows images to be played back.

A beam index type color television receiver using a beam index type color picture tube has previously been proposed. This beam-indexed color picture tube has a single electron beam and a color phosphor surface with horizontally arranged red, green, and blue color phosphor stripes. Index phosphor stripes are arranged horizontally on the inner surface, and the index signal obtained by scanning the index phosphor stripes with an electron beam is e.g.
The signal is supplied to a PLL circuit, and color switching is performed based on the output signal of this PLL circuit, so that when the electron beam scans the red color phosphor stripe, the red primary color signal is used to scan the green color phosphor stripe. The density is modulated using a green primary color signal when scanning, and a blue primary color signal when scanning a blue phosphor stripe. Further, this beam index type color television receiver will be described with reference to FIG. 1. In FIG. is provided, and this photodetector 2
The output signal of is supplied to the bandpass filter 3,
An index signal with a frequency determined by the pitch of the index phosphor stripe and the scanning speed of the electron beam is extracted, and this index signal is supplied to the phase comparator 5 of the PLL circuit 4, and the output pulse of the voltage controlled oscillator 6 is frequency-divided. The divided pulse is supplied to the phase comparator 5, and the output voltage of the phase comparator 5 is supplied to the low-pass filter 8, and the control signal obtained at the output side of the low-pass filter 8 is The oscillation frequency of the voltage controlled oscillator 6 is controlled by the voltage controlled oscillator 6, and the frequency of the index signal is N times that of the index signal, that is, one of the color phosphor stripes.
A pulse signal with a frequency three times the so-called triplet frequency, which is determined by the pitch of the pair and the scanning speed of the electron beam, is obtained. A signal with a frequency three times this triplet frequency is supplied to a gate pulse generator 9 consisting of a ring counter, and an index signal from the bandpass filter 3 is supplied to a mode set pulse generator 10, which generates a mode set pulse. 3 to gate the red, green and blue primary color signals obtained from the output side of the gate pulse generator 9.
The gate pulses are supplied to the gate circuit 11 to generate red, green and blue primary color signals E _R , E _G and E which are supplied to the color signal supply terminals 11 a, 11 b and 11 c. _B are sequentially taken out, and the switched primary color signals are supplied to the first grid 13 of the color picture tube 1 through the drive circuit 12. In FIG. 1, 14 is a cathode power supply, 15 is a horizontal deflection means,
16 is a horizontal deflection circuit, and 17 is a high voltage circuit.

In FIG. 1, under normal conditions, an index signal is detected by the photodetector 2 according to the deflection of the electron beam, and this index signal is sent from the bandpass filter 3 to the phase comparator of the PLL circuit 4. 5, the output pulse of the voltage controlled oscillator 6 is frequency-divided by the frequency divider 7, and the frequency-divided pulse is supplied to the phase comparator 5.
The output voltage of the phase comparator 5 is supplied to the low pass filter 8, and the output voltage of the phase comparator 5 is supplied to the low pass filter 8.
The oscillation frequency of this voltage-controlled oscillator 6 is controlled by a control voltage corresponding to the frequency of the index signal obtained on the output side of A frequency signal is obtained, and based on this signal, the color of the color picture tube is switched to reproduce a color image.

However, in the PLL circuit 4 shown in FIG. 1, a control voltage corresponding to the frequency of the index signal is supplied from the output side of the low-pass filter 8 to the control voltage supply terminal of the voltage controlled oscillator 6. However, when the frequency of this index signal changes suddenly, band pass filter 3, low pass filter 8, etc. are used to detect this, so the control voltage is adjusted according to this frequency change. It takes a certain amount of time to obtain this. For this reason, the high voltage from the high voltage terminal of the high voltage circuit 17 that is supplied to the anode of the color picture tube 1 suddenly fluctuates for some reason, the deflection speed of the electron beam increases or decreases, and the frequency of the index signal suddenly changes. When the index signal fluctuates, the PLL circuit 4 is unable to follow the frequency fluctuation of the index signal, and the output signal of the voltage controlled oscillator 6 cannot be correctly controlled. However, color shift occurs due to a difference in the timing of color switching.

In view of this point, the present invention is designed to improve the ability of the PLL circuit 4 to follow changes in the index signal frequency due to changes in high voltage.

Hereinafter, an embodiment of the beam index type color television receiver of the present invention will be described with reference to FIG. In FIG. 2, parts corresponding to those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 2, reference numeral 18 indicates a voltage supply terminal for supplying DC voltage, and this voltage supply terminal 18 is grounded through a series circuit of resistors 19 and 20, and the resistors 19 and 20 are connected to each other. The voltage obtained at the point is supplied to the adding circuit 21. In this case, resistor 1
9 and 20, V _p /2V _Hp V _Hp (where V _Hp is the reference high voltage, and V _p is the deflection speed of the electron beam when the high voltage is equal to the reference high voltage V _Hp . ) to obtain the voltage according to the resistor 19.
and 20 resistance values are set, respectively. Also high voltage circuit 1
The high voltage output terminal of 6 is grounded through a series circuit of resistors 22 and 23.
The voltage obtained at the mutual connection point of the inverter circuit 2
4 to the adder circuit 21. in this case,
V _p /2V _Hp V _H(
t) The resistance values of the resistors 22 and 23 are respectively set so as to obtain a voltage corresponding to V _{H(t) (V H(t)} is the value of the high voltage). Further, the high voltage output terminal of the high voltage circuit 17 is grounded through a series circuit of a capacitor 26 and a resistor 27 that constitute a differentiating circuit 25, and the differential voltage d/ dtV _H(t) is supplied to one input side of the multiplier circuit 28, and an information signal x _{H( t)} to the other input side of the multiplier circuit 28, the output side of this multiplier circuit 28 is grounded via a series circuit of resistors 29 and 30,
The voltage obtained at the connection point of the resistors 29 and 30 is passed through an inverter circuit 31 to an adder circuit 21.
supply to. In this case, the resistance values of resistors 29 and 30 are set so that a voltage corresponding to 1/2V _Hp x _H(t) x d/dtV _H(t) is obtained at the mutual connection point of resistors 29 and 30. . Further, the output side of the adder circuit 21 is connected to one input side of the adder circuit 33 via the DC amplifier 32, and the output side of the low-pass filter 8 is connected to the adder circuit 3 through the DC amplifier 32.
3, and the output side of this adder circuit 33 is connected to the control voltage supply terminal of the voltage controlled oscillator 6. The rest of the structure is the same as in FIG.

Since the present invention is configured as described above, when the value of the high voltage is V _H(t) , the voltage obtained from the output side of the adder circuit 21 is -v _p /2V _Hp (V _H(t) −
V _{H p} )-1/2V _Hp x _H(t) x d/dt A voltage corresponding to V _H(t) is obtained, and this voltage is further adjusted to an appropriate level via the DC amplifier 32, and the low frequency Pass filter 8
This added signal is supplied to the control voltage supply terminal of the voltage controlled oscillator 6.

By the way, when the high voltage varies from the reference high voltage V _Hp to V _H(t) , the variation error Δv(t) in the deflection speed of the electron beam is expressed as Δv(t)=-v _p /2V _Hp (V _{H( t)} −V _Hp ) −1/2V _Hp x _H(t) ×d/dtV _H(t) ……(1
) is known to be.

Also, at this time, since the fluctuation of the index signal frequency supplied to the phase comparator 5 of the PLL circuit 4 changes according to the fluctuation error Δv(t) of the deflection speed of the electron beam, the frequency signal corresponding to this index signal is It is necessary to output from the output side of the voltage controlled oscillator 6, and for this purpose, the control voltage V _S applied to the control voltage supply terminal of the voltage controlled oscillator 6 when the voltage value of the high voltage is V _Hp . In addition, the fluctuation error Δv of the deflection speed of the electron beam
The control voltage V _C according to (t) is applied to the low pass filter 8.
It is necessary to apply it to the control voltage supply terminal from the output side of the control voltage.

In the case of the present invention as shown in FIG. 2, the signal added to the output signal of the low-pass filter 8 of the PLL circuit 4 depends on the fluctuation error Δv(t) of the deflection speed of the electron beam due to fluctuations in the high voltage. Therefore, by adjusting the level of this signal to the level of V _C using the DC amplifier 32 etc., it is possible to supply a control voltage completely equivalent to V _C to the control voltage supply terminal of the voltage controlled oscillator 6. .

In this way, in the case of the present invention, when the index signal fluctuates rapidly due to fluctuations in the high voltage, the control voltage corresponding to this frequency fluctuation can be obtained without passing through the band pass filter 3 and the low pass filter 8. Because it is directly obtained, the voltage controlled oscillator 6
The oscillation frequency of the index signal can follow the rapid frequency fluctuations of the index signal extremely well, and the voltage controlled oscillator 6 can obtain a signal with a frequency corresponding to the fluctuation of the high voltage, and can reproduce a good color image. can.

3, 4 and 5 respectively show other embodiments of the beam index type color television receiver of the present invention. In FIGS. 3, 4, and 5, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 3, an attempt is made to detect high voltage fluctuations using the anode current supplied to the color picture tube 1, and the terminal of the high voltage circuit 17 is grounded via a resistor 34 for detecting the anode current. Vessel 34
The voltage obtained across the terminals is supplied to the multiplier circuit 28,
The output side of this multiplier circuit 28 is connected to resistors 29 and 30.
is grounded through a series circuit of the resistors 29 and 30, and the voltage obtained at the mutual connection point of the resistors 29 and 30 is added to the adding circuit 21.
supply to. In this case, -
In order to obtain a voltage according to I _{a (t)} /C (I _{a (t)} is the anode current, and C is the capacitance formed by the conductive coatings applied to the inside and outside of the color picture tube 1, respectively). Set the resistance value of the resistor 34. The rest of the structure is the same as in FIG. 2.

3 is constructed as described above, and the adder circuit 2
The voltage obtained at the output side of 1, adjusted to an appropriate level via the DC amplifier 32, and added to the output signal of the low-pass filter 8 of the PLL circuit 4 is -v _p /2V _Hp (
V _{H (t)} −V _Hp )+1/2V _Hp x _H(t) ×I _a(t) The voltage corresponds to /C, and in the above equation (1), d/dtV _H(t) = −1 /CI _a(t
) Δv(t)=-v _p /2V _Hp (V _H(t) -V _Hp ) +1/2V _Hp x _H(t) ×I _a(t) /C...(2
), and in this figure 3, the voltage is also the same as the second
It is easy to understand that it has the same effect as shown in the figure.

In addition, FIG. 4 differs from the control signal in FIGS. 2 and 3 in which the control signal is obtained by focusing on the fluctuation in the index signal frequency, that is, the fluctuation error Δv(t) in the deflection speed of the electron beam. It is known that in the case of high pressure fluctuations, the magnitude of Δv(t) is small, but the change in the fluctuation error of the deflection speed of the electron beam d/dtΔv(t) becomes large, and this d/dtΔv(t) It is also effective to obtain a control signal by focusing only on the variation error of the deflection speed of the electron beam, d/dtΔv(t). This is to improve the followability of.

For this reason, in FIG. 4, the high voltage output terminal of the high voltage circuit 17 is grounded through a series circuit of a capacitor 36 and a resistor 37 that constitute the differentiating circuit 35, and the capacitor 36 and resistor 37 are connected to each other. The connection point is connected through a buffer amplifier 38 to resistors 39 and 4.
The voltage obtained at the connection point of the resistors 39 and 40 is supplied to the adder circuit 42 via the inverter circuit 41. In this case, the high voltage V _H(t) is differentiated by the differentiating circuit 35 to obtain a voltage of d/dtV _H(t) at the mutual connection point of the capacitor 36 and the resistor 37, and the resistor 39 and 40 mutual connection points v _p /V _Hp d/dtV _H
The resistance values of resistors 39 and 40 are set respectively so as to obtain a voltage corresponding to _(t) . Further, the output side of the buffer amplifier 38 is grounded through a series circuit of a capacitor 44 and a resistor 45 that constitute a differentiating circuit 43, and a differential signal obtained at the connection point of this capacitor 44 and resistor 45 is applied to a multiplier circuit 46. This multiplier circuit 46 supplies the information signal x _H(t) of the horizontal deflection magnitude (zero at the center) due to the horizontal deflection obtained from the horizontal deflection circuit 16 to one input side of the multiplier circuit 46. The output side of this multiplier circuit 46 is grounded through a series circuit of resistors 47 and 48, and the voltage obtained at the connection point of these resistors 47 and 48 is applied to an inverter circuit 49. is supplied to the adder circuit 42 via. In this case, the differential voltage d/dtV _H(t) obtained from the output side of the buffer amplifier 38 is differentiated again by the differentiating circuit 43, and d ² /dt ² V _{H( t)} so as to obtain a voltage of
Furthermore, 1/2V _Hp x is applied to the mutual connection point of resistors 47 and 48.
The resistance values of the resistors 47 and 48 are respectively set so as to obtain a voltage corresponding to _{H (t)} ×d ² /dt ² V _H(t) . Further, the output side of the adder circuit 42 is connected to one input side of the adder circuit 51 via the DC amplifier 50, and the output side of the phase comparator 5 of the PLL circuit 4 is connected to the other input side of the adder circuit 51. , the output side of this adder circuit 51 is connected to the input side of the low-pass filter 8. The rest of the structure is the same as that shown in FIG.

FIG. 4 shows the configuration as described above, which is obtained at the output side of the adder circuit 42, is made to an appropriate level via the DC amplifier 50, and is passed through the low-pass filter 8 of the PLL circuit 4.
The voltage added to the input signal of is a voltage according to -v _p /V _Hp d/dtV _H(t) -1/2V _Hp x _H(t) ×d ² /dt ² V _H(t) , and the electron The variation d/dtΔv(t) of the beam deflection speed fluctuation error, that is, the above equation (1) was differentiated.

d/dtΔv(t)=-v _p /V _Hp d/dtV _H(t) -1/2V _Hp x _H(t) ×d ² /dt ² V _H(t) ...
…The voltage will be according to (3). By the way, in FIG. 4, the control voltage obtained by the adder circuit 42 is added to the input signal of the low-pass filter 8 of the PLL circuit 4, but this is due to the change d/of the fluctuation error of the deflection speed of the electron beam. Since the control signal focuses on dtΔv(t), it is supplied as an input signal to the low-pass filter 8, that is, the integration circuit, and as a result, the control voltage supply terminal of the voltage controlled oscillator 6 receives fluctuations in the index signal frequency. A control voltage corresponding to the voltage is supplied.

In this way, it can be easily understood that this FIG. 4 also has the same effect as FIG. 2.

In Fig. 5, a control signal is obtained by focusing on the change in the fluctuation error of the deflection speed of the electron beam due to high voltage fluctuation, that is, d/dtΔv (t), and this is used to control the PLL.
This improves the followability of the circuit 4.

In FIG. 5, the high voltage detection terminal of the high voltage circuit 17 is grounded via a resistor 52 for detecting anode current, and this high voltage detection terminal is also grounded via a series circuit of resistors 53 and 54. Resistor 53
and 54 are supplied to an adder circuit 56 via an inverter circuit 55. In this case, at the mutual connection point of resistors 53 and 54 -
resistor 5 to obtain a voltage according to v _p /CV _Hp I _a(t)
3 and 54, respectively. Also high voltage circuit 17
The high voltage detection terminal of
This capacitor 59 is grounded through a series circuit of
The voltage obtained at the connection point of the resistor 60 and the resistor 60 is supplied to one input side of the multiplier circuit 61, and an information signal indicating the horizontal deflection of the electron beam due to horizontal deflection obtained from the horizontal deflection circuit 16 is supplied. x _H(
t) to the other input side of this multiplier circuit 61,
The output side of this multiplier circuit 61 is connected to resistors 62 and 63.
The voltage obtained at the connection point of the resistors 62 and 63 is supplied to the adder circuit 56 via the inverter circuit 64. In this case, -1/2CV _H is connected to the mutual connection point of resistors 62 and 63.
The resistance values of the resistors 62 and 63 are set so as to obtain a voltage according to _p x _H(t) x d/dtI _a(t) . Further, the output side of the adder circuit 56 is connected to one input side of the adder circuit 51 via the DC amplifier 50.

The rest of the structure is the same as that shown in FIG. 4.

FIG. 5 shows the configuration as described above, which is obtained at the output side of the adder circuit 54, is brought to an appropriate level via the DC amplifier 50, and is passed through the low-pass filter 8 of the PLL circuit 4.
The voltage applied to the input voltage is v _p /CV _Hp I _a(t) + 1/2CV _Hp x _H(t) × d/dtI _a(t) , and in the above equation (3), d /dtV _H(t
) =-I _a(t) d/dtΔv(t)=v _p /CV _Hp I _a(t) +1/2CV _Hp x _H(t) ×d/dtI _a(t) ... …
(4), and in this Fig. 5, the voltage corresponds to
It is easy to understand that it has the same effect as shown in the figure.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a beam index type color television receiver, FIG. 2 is a system diagram showing an embodiment of the beam index type color television receiver of the present invention, and FIGS. Figure and 5th
The figures are system diagrams showing other embodiments of the present invention. 1 is a beam index type color picture tube, 2 is a photodetector, 4 is a PLL circuit, 5 is a phase comparator, 6 is a voltage controlled oscillator, 7 is a frequency divider, 8 is a low pass filter, 16 is a horizontal deflection circuit, 17 is a high voltage circuit, 1
8 is a voltage supply terminal, 19, 20, 22, 23, 2
9 and 30 are resistors, 21 and 33 are adder circuits, 24 and 31 are inverter circuits, and 2
5 is a differentiating circuit, 28 is a multiplication circuit, and 32 is a DC amplifier.

Claims (1)

[Claims] 1 Equipped with a PLL circuit to which index signals from a beam index type color picture tube are supplied;
In a beam index type color television receiver configured to switch the color of the color picture tube based on the output signal of the PLL circuit, the fluctuation of the high voltage supplied to the color picture tube or The differential value is obtained from the high voltage circuit,
A signal corresponding to the variation of the high voltage or its differential value is added to the output signal or input signal of the low pass filter of the PLL circuit to control the voltage controlled oscillator of the PLL circuit. A beam index type color television receiver characterized in that the followability of the PLL circuit to fluctuations is improved.