JPS6199467A - Television receiver of multiscanning type - Google Patents

Abstract

PURPOSE:To modulate the scanning speed of an electron beam well even for input signals different in horizontal frequency by detecting a horizontal deflecting frequency of a horizontal deflecting circuit which is switched in accordance with the horizontal frequency of the input signal and controlling the modulation quantity of the scanning speed by this detection output. CONSTITUTION:The luminance signal of an RGB process circuit 3 is supplied to the first differentiating circuit 80, and the differential output is supplied to an AGC circuit 82 incorporating the second differentiating circuit through a noise eliminating circuit 81 which eliminates signals having a certain amplitude or narrower. The output of this AGC circuit 82 is supplied as a scanning speed modulating signal to a terminal G for scanning speed modulation of a cathode-ray tube 6 and a detecting circuit 83 of a peak-to-peak value of the modulation quantity of the scanning speed, and the detection output of the detecting circuit 83 is supplied to the gain control terminal of the AGC circuit 82. Meanwhile, the horizontal synchronizing signal from a synchronizing signal separating circuit 7 is supplied to a frequency discriminator 84, and the output signal is supplied to a time constant control terminal of the AGC circuit 82. In this case, the time constant of the AGC circuit 82 is made larger in proportion to the input frequency of the frequency discriminator 84.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention can be used to increase the number of scanning lines to 2 in addition to normal television broadcast image reception.
The present invention relates to a multi-scan television receiver capable of receiving video signals of different horizontal frequencies from a converter or the like that performs double conversion.

[Conventional technology]

For example, in an NTSC television signal, the vertical frequency is approximately 6011Z and the horizontal frequency is approximately 15.75X) lz
The image is formed. In response to this, a conversion device has been proposed that doubles the number of scanning lines through arithmetic processing or the like to improve the quality of the received image. When using this device,
The signal to be outputted now has a vertical frequency of about 6011 z and a horizontal frequency of about 31.5 KHz.

In addition, some output signals from computers with a so-called M1 resolution table have a horizontal frequency of about 24 KHz.

Also, in so-called high-definition television, the horizontal frequency is approximately 33
．． 75XIIz is scheduled.

Currently, a multi-scanning television receiver has been proposed which allows a single device to receive various signals having different frequencies.

First, a multi-scan television receiver proposed by the applicant will be explained with reference to FIGS. 4 to 6.

FIG. 4 shows an overall block diagram. In this figure, a normal television broadcast tuner or video tape recorder,
When receiving regular video signals from a video disc player, satellite broadcast Nayuna, some personal computers, etc., the video signal supplied to the input terminal (1) undergoes RGB processing through the video processing circuit (2). The three primary color signals are supplied to the circuit (3) to form three primary color signals.

In addition, the video/RGB switching signal supplied to the input terminal (4) is supplied to the RGB processing circuit (3), whereby the three primary color signals from the selected video (No. 8) are sent to the cathode ray tube (5) through the output circuit (5). 6).

In addition, the video signal from the input terminal (1)
3 fil, and vertical and horizontal synchronization signals are separated. Furthermore, the switching signal from the input terminal (4) is supplied to the synchronization separation circuit (7), whereby the vertical synchronization signal from the selected video signal is supplied to the vertical deflection circuit (8), and a vertical deflection signal is formed. is supplied to the vertical deflection yoke (9) of the cathode ray tube (6). Also, synchronous separation circuit (7)
The horizontal synchronizing signal from the video signal selected in is supplied to the AFC circuit αω and the mode detection circuit (11), and this A
A signal from the FC circuit α0 is supplied to the horizontal oscillation circuit (12), and a normal control signal from the mode detection circuit (11) is supplied to the horizontal oscillation circuit (12). The signal from this horizontal oscillation circuit (12) is transmitted to the horizontal deflection circuit (
13) and the formed horizontal deflection signal is applied to the cathode ray W.
Further, the signal from the horizontal deflection circuit (13) is supplied to the high voltage 1 generation circuit 1i (15) such as a flyback transformer, and the high voltage generated is supplied to the cathode ray tube (14). 6), and a part of the signal is also supplied to the AFC circuit Q.

In addition, the commercial power supply from the power source (17) is 1 m long (
18), and a normal voltage according to the signal from the mode detection circuit (11) is supplied to the horizontal deflection circuit (13). Also, commercial power from the power supply input (17) is supplied to another power supply circuit (19), and the voltage formed is supplied to other circuits.

As a result, the actual video signal is received. On the other hand, the digital or analog R, G and
When receiving three primary color signals (hereinafter referred to as RGB signals), input terminals (20R) (20G) (
The digital RGB signal supplied to the input terminals (20B) and the analog RGB signal supplied to the input terminals (21R) (21G) (21B) are selected by the changeover switch (22) and supplied to the ROB process circuit (3). , selected by a switching signal from the input terminal (4) and supplied to the output circuit (5).

Further, the digital synchronization signal from the input terminal (20S) and the analog synchronization signal from the input terminal (21S) are selected by the changeover switch (23) and supplied to the synchronization separation circuit (7), and the input terminal (4) It is selected by a switching signal from and supplied to the vertical deflection circuit (8) and the AFCl path αω. Furthermore, the signal from the synchronization separation circuit (7) is transmitted to the mode detection circuit (
11), a control signal corresponding to the frequency of the horizontal synchronization signal is formed, and the control signal is supplied to a horizontal oscillation circuit (12), a horizontal deflection circuit (13), and a power supply circuit (18).

As a result, digital or analog RGB signals are received. Furthermore, when performing so-called superimposed image reception in which an RGB signal is superimposed on the above-mentioned school video signal, the switching signal supplied to the input terminal (4) is set to RGB mode, and the input terminal (24)
Ys indicates the position of the superimposed signal supplied to the signal and Y indicates the superimposed range.
The m signal is supplied to the RGB processing circuit (3), and switching between the video signal and the RGB signal is performed between these Ys and Ym signals.

Various signals are received in the manner described above.

Furthermore, in the above-mentioned apparatus, the horizontal deflection system is specifically constructed as shown in FIG. In Fig. 5, the synchronization separation circuit (
The horizontal synchronization signal from 7) is sent to the horizontal synchronization signal input terminal (71
1) to a frequency-voltage conversion circuit (FVC) (31) constituting the mode detection circuit (11) to form a voltage according to the horizontal frequency. This F'VC (31)
The output voltage of one fixed contact of the changeover switch (32) (
32b), and the other fixed contact (32c) of this changeover switch (32) is grounded via a reference voltage source (33). In this case, the voltage value of this reference voltage source (33) is equal to the voltage value obtained when the horizontal synchronizing signal of Ilz is supplied to the input side of the FVC (31), for example, at a horizontal frequency of 15.75 in the NTSC system. Set. In addition, this changeover switch (32) has an input terminal (4) connected to its control terminal.
) is supplied via the video ROB switching signal input terminal (4a), and the video/RGB switching signal from
When the GB switching signal indicates video signal input, the movable contact (32a) of the changeover switch (32) switches to the other fixed contact (3
2c), and the video/ROB switching signal is RGB
The movable contact (32a) of the fW manpower/military power changeover switch (32) is connected to one fixed contact (32b). The voltage obtained at the movable contact (32a) of this changeover switch (32) is supplied through a buffer amplifier (34) to a voltage controlled oscillator (VCO) (35) constituting the horizontal oscillation circuit (12).

The oscillation output of this VCO (35) drives the drive circuit (36)'
The signal is then supplied to a switching transistor (37) constituting a horizontal deflection circuit (13).

Further, the voltage obtained at the movable contact (32a) of the changeover switch (32) is supplied through the gain control amplifier (38) to a Y-Z type parametric power supply circuit (39), which constitutes one power circuit (18). . This electronic circuit (39
) is fed back to the gain 111 control amplifier (38) through the voltage divider circuit (40) to stabilize the output voltage. This output voltage is supplied to the flybank transformer (41).

A switching transistor (37) is connected in series to this flybank transformer (41). Further, a damper diode (42), a resonant capacitor (43), and a series circuit of a horizontal deflection yoke (14) and an S-shaped correction capacitor (44) are connected in parallel to this switching transistor (37).

In addition, the horizontal synchronization signal is supplied to the detection circuit (45) that constitutes the AFC circuit (l [ll), and the voltage divider circuit (46) provided in series with the switching transistor (37).
A signal from is supplied to a detection circuit (45) to form an FC signal. This signal is a low pass filter (LPF)
(47) is supplied to the control terminal of the VCO (35).

Furthermore, a switch circuit (
Capacitors (49) and (50) are connected through 48). In addition, capacitors (52) (53) are connected in parallel to the S-shaped correction capacitor (44) through a switch circuit (51).
) are connected. Further, the voltage from the FVC (31) is supplied to a comparator circuit (54) for binary comparison corresponding to the input horizontal frequency of 20 Hz and 30 KHz, for example.
A three-value comparison output corresponding to each range of 0 KHz or less, 20 to 30 KHz, and 30 KHz or more is formed, and two switches built in the switch circuits (48) and (51) are activated according to the comparison output. Control is performed so that both are off or one of them is on.

As a result, in this horizontally deflected yarn, VCO (35
), an oscillation signal that varies from 15 to 34 KHz in synchronization with the human-powered horizontal synchronization signal is formed to perform horizontal deflection, and the power supply circuit (39) varies from 58 to 123 volts, for example, depending on the horizontal frequency. A voltage is generated to control the amplitude of the horizontal deflection to be constant. Also, a resonance capacitor (43) and an S-shaped correction capacitor (44)
) in parallel with the capacitor (4
9) ' (50) and (52) (53) are connected,
The characteristics of each are corrected.

Further, in the above-described apparatus, the vertical deflection system is specifically configured as follows. In Fig. 6, the synchronous separation circuit (7
) is the vertical sync signal input terminal (7v)
is supplied to the sawtooth wave oscillator (61) constituting the vertical deflection circuit (8) through, for example, a condenser! ) (62) is charged and discharged by the current of the current source (63) to form a sawtooth wave. This sawtooth wave is supplied to a comparator circuit (64) to form a 3-value comparison output indicating a predetermined voltage range and below or above, and this comparison output is sent to a 7-sop down counter (U
DC) is supplied to the control terminal of (65). This U.D.
A vertical synchronization signal is supplied to the counting terminal of C (65). The count value of this UDC (65) is the DA conversion circuit (DAC) (
66) and converts the converted analog value into a current source (
63) is controlled.

Therefore, from the sawtooth wave oscillator (61)! l! Direct synchronous 1
A sawtooth wave whose wave crystal value (amplitude) is controlled within a predetermined voltage range is extracted regardless of the No. 6 frequency. This sawtooth wave is supplied to the vertical deflection yoke (9) through an output circuit (67). Furthermore, a series circuit of a capacitor (68) and a resistor (69) is connected in series to this deflection yoke (9), and a voltage dividing circuit (70) is connected in parallel to this resistor (69). The divided voltage output of this voltage dividing circuit (7o) is the output circuit (67
).

This provides a constant amplitude vertical deflection even if the vertical frequency changes. Further, by using a J-shaped resistor as one of the resistors constituting the voltage dividing circuit (7o), the amplitude of the vertical deflection can be arbitrarily controlled.

In addition, one saw-shaped JJiW (61) ~ DAC (6
6) (7) Another set of circuits (oscillator (71) to DAC
(76) ), and the output value of the DAC (76) of this circuit is supplied to the pin distortion correction signal forming circuit (77).
A parabolic signal with a vertical period from the connection midpoint of forms a circuit (
77) to form a pin distortion correction signal. Each signal is supplied to the bin distortion correction circuit.

In this way, in the above-mentioned apparatus, the necessary horizontal and vertical deflections are performed according to various different horizontal and vertical frequencies, and various signals are received.

[Problem that the invention seeks to solve]

Conventionally, the horizontal scanning speed of the electron beam is accelerated or slowed down at the boundary between bright and dark images, using so-called scanning speed modulation.
The outline of the image is sharpened. In this scanning speed modulation, the scanning speed modulation signal as shown in FIG.
6) to the terminal for scanning speed modulation of the fourth grid,
The scanning speed is varied as shown in FIG. 7A by electrostatically deflecting the electron beam in accordance with the amount of scanning speed modulation.

However, in the multi-scan television receiver described above, since the horizontal frequency of the input signal is not constant, when the horizontal frequency increases, the scanning speed modulation as shown in Figure 8B, which is obtained by second-order differentiation of the image signal, occurs. Signal scanning speed liquid 1l
The peak-to-peak value of Il amount becomes larger than necessary,
It has become clear that when the scanning speed is varied by electrostatically deflecting the electron beam using this scanning speed modulation amount, the electron beam goes backwards at the boundary between bright and dark images, as shown in FIG. 8A.

In view of these points, the present invention seeks to propose an apparatus that can satisfactorily modulate the scanning velocity of an electron beam even for input signals having different horizontal frequencies.

[Means for solving problems]

The present invention detects the horizontal frequency of a multi-scan television receiver input signal, converts it into a voltage, applies this voltage to a horizontal deflection circuit (13), and switches the horizontal deflection frequency of this horizontal deflection circuit (13). In a multi-scan television receiver that receives input signals of different horizontal frequencies, the horizontal deflection frequency is detected and the amount of scanning speed modulation is controlled based on the detected output.

[Effect]

According to such a configuration, the horizontal deflection frequency of the horizontal deflection circuit (13), which is switched according to the horizontal frequency of the input signal, is detected, and the scanning speed modulation amount is controlled by this detection output, so that the horizontal deflection frequency of the horizontal deflection circuit (13) is controlled depending on the horizontal frequency of the input signal. The scanning speed modulation of the electron beam can be performed well even for

〔Example〕

Hereinafter, an embodiment of the multi-scan television receiver of the present invention will be described with reference to FIGS. 1 to 3. In FIGS. 1 to 3, parts corresponding to those in FIGS. 4 to 6 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, as shown in FIG. 1, the luminance signal of the RGB process circuit (3) is supplied to the first differentiation circuit (80),
The differential output of this first differentiating circuit (80) is
is supplied to an AGC circuit (82) in which a second differentiation circuit is incorporated via a noise removal circuit (81) that removes the signal;
The output signal of this AGC circuit (82) is used as a scanning velocity modulation signal to be sent to the terminal G for scanning velocity modulation of the fourth grid of the cathode ray tube (6) and to the peak-to-peak value detection circuit (83) of the amount of scanning velocity modulation. The detection output of this detection circuit (83) is supplied to the gain control terminal of the AGC circuit (82). In this case, the AGC circuit (82nd detection circuit (83)
The peak-to-peak value of the scanning speed modulation amount is controlled to a predetermined value based on the detected output.

On the other hand, the horizontal synchronization signal from the synchronization separation circuit (7) is supplied to the frequency discriminator (84), and the output (g) of the frequency discriminator (84) is connected to the time constant control terminal of the AGC circuit (82) (7). In this case, the time constant of the AGC circuit (82) is made to increase in proportion to the input frequency of the frequency discriminator (84).

The other horizontal deflection threads, vertical deflection threads, etc. are constructed in the same manner as in the multi-scan television receiver shown in FIGS. 4 to 6 above.

According to this configuration, the horizontal frequency is approximately 15.734KH.
When the video of z (number g is input to input terminal (1),
The video signal is converted into RGB via the video processing circuit (2).
The three primary color signals of this RGB process circuit (3) are supplied to the cathode ray I tube (6) via the output circuit (5), and the luminance signal of the RGB process circuit (3) is supplied to the cathode ray I tube (6). The signal is supplied to the AGC circuit (82) via the differential circuit (8o) of No. 1 and the noise removal circuit (81).

At this time, the output signal of the frequency discriminator (84) obtained by frequency discriminating the horizontal synchronization signal of about 15.734 Hz from the synchronization separation circuit (7) causes the time constant of the AGC circuit (82) to change to the horizontal deflection frequency. It is set to a predetermined value corresponding to approximately 15.734 KHz, second-order differentiation is performed in this AGC circuit (82), and the peak-to-peak value is set to a predetermined value by the detection output of the detection circuit (83). Scanning speed change as shown in B)! The 11th number is the 4th one of the cathode ray tube (6)
It is applied to terminal G for modulating the scanning speed of the grid. Therefore, the electron beam is electrostatically deflected by a scanning velocity modulation signal having a predetermined scanning velocity modulation amount as shown in FIG. 2B, and the scanning velocity of the electron beam is well modulated as shown in the second image.

Also, if the horizontal frequency is relatively high, for example about 31.468KH
When the video signal of z is input manually to the input terminal (11), the video signal is supplied to the RGB process circuit (3) via the video process circuit (2), and the three primary color signals of this RGB process circuit (3) are output to the output circuit. (5) to the cathode ray tube (6), and the luminance signal of the RGB process circuit (3) is supplied to the first differentiating circuit (80) and the noise removing circuit (
81) to the AGC circuit (82).

At this time, approximately 31.4613 from the synchronous separation circuit (7)
The time constant of the AGC circuit (82) is set to a predetermined value corresponding to when the horizontal deflection frequency is about 31.468 Hz by the output signal of the frequency discriminator (84) obtained by frequency discriminating the KHz horizontal synchronization signal, Second-order differentiation is performed in this AGC circuit (82), and the peak-to-peak value is set to a predetermined value by the detection output of the detection circuit (83).The scanning speed modulation signal as shown in FIG. ) is applied to the terminal G for scanning speed modulation of the fourth grid. For this reason, the electron beam is stabilized by a scanning velocity modulation signal having a predetermined scanning velocity modulation amount as shown in FIG. 3B. 1f deflected, 3rd
As shown in Figure A, the scanning velocity of the electron beam can be modulated well.

As described above, according to this example, the horizontal frequency of input No. 13 is detected and converted into a voltage, and this voltage is converted into a horizontal deflection circuit (1
In addition to 3), in a multi-scan television receiver that switches the horizontal deflection frequency of the horizontal deflection circuit (13) to receive input signals of different horizontal frequencies, the horizontal deflection frequency is detected, and the scanning speed is determined by the detection output. Since the amount of modulation is controlled, there is an advantage that the scanning speed of the electron beam can be modulated well even for input signals having different horizontal frequencies.

However, it goes without saying that the present invention is not limited to the above-described embodiments, and can take various other configurations without departing from the gist of the present invention.

〔Effect of the invention〕

According to the multi-scanning television receiver of the present invention, the scanning speed of the electron beam can be modulated well even for input signals with different horizontal frequencies, and there is an advantage that a good image with sharp edges can be obtained. .

Explanation of the drawings Fig. 1 is a configuration diagram showing an embodiment of the essential parts of the multi-scanning television receiver of the present invention, and Figs.
4 is a block diagram showing an example of a multi-scan television receiver, FIG. 5 is a block diagram showing the horizontal deflection system extracted from FIG. 4, and FIG. The vertical deflection system in Figure 4 is extracted and shown in Figures 7 and 8.
The figure is a diagram for explaining the scanning speed modulation.

(3) is an RGB process circuit, (6) is a cathode ray tube, (7
) is a synchronous separation circuit, (80) is a first differentiation circuit, (81
) is a noise removal circuit, (82) is an AGC circuit, (83) is a detection circuit, (84) is a frequency discriminator, and G is a terminal for scanning speed modulation of the fourth grid of the cathode ray tube.

Figure 1 Figure 2 Figure 3 A A Day 1 hour - Ichiya Akima Measuring Figure 8 1-Yu 1 Listen Run luxury

Claims (1)

[Claims] A multi-scan television receiver that detects the horizontal frequency of an input signal, converts it into a voltage, applies the voltage to a horizontal deflection circuit, and switches the horizontal deflection frequency of the horizontal deflection circuit to receive input signals of different horizontal frequencies. 2. A multi-scan television receiver, characterized in that the horizontal deflection frequency is detected and the amount of scanning speed modulation is controlled based on the detected output.