JPH0646784B2 - Multi-scan type TV receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses a scanning line number of 2 in addition to a normal television broadcast image reception.
The present invention relates to a multi-scanning television receiver capable of receiving video signals having different horizontal frequencies from a converting device for double conversion.

[Conventional technology]

For example, in an NTSC television signal, an image is formed with a vertical frequency of about 60 Hz and a horizontal frequency of about 15.75 KHz. On the other hand, a conversion device has been proposed in which the number of scanning lines is doubled by arithmetic processing or the like to improve the image quality of an image received. When using this device, the signal output from this device has a vertical frequency of about 60 Hz and a horizontal frequency of about 31.5 KH.
It is z.

In addition, there is a so-called high-resolution display computer output signal having a horizontal frequency of about 24 KHz. Also, in so-called high-definition television, the horizontal frequency is scheduled to be approximately 33.75 KHz.

At present, there has been proposed a multi-scanning television receiver capable of receiving various signals having different horizontal frequencies with a single device.

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

FIG. 4 shows an overall block diagram. In this figure, a normal TV broadcast tuner or video tape recorder,
When receiving a normal video signal from a video disc player, satellite broadcast tuner, some personal computers, etc., the video signal supplied to the input terminal (1) is an RGB process circuit through the video process circuit (2).
It is supplied to (3) and the three primary color signals are formed. The video / RGB switching signal supplied to the input terminal (4) is RGB
The three primary color signals from the video signal selected by the process circuit (3) are supplied to the cathode ray tube (6) through the output circuit (5).

Further, the video signal from the input terminal (1) is supplied to the sync separation circuit (7) to separate the vertical and horizontal sync signals. Further, the switching signal from the input terminal (4) is supplied to the sync separation circuit (7), the vertical synchronization signal from the video signal selected by this is supplied to the vertical deflection circuit (8), and the formed vertical deflection signal is formed. Are supplied to the vertical deflection yoke (9) of the cathode ray tube (6). The horizontal sync signal from the video signal selected by the sync separation circuit (7) is supplied to the AFC circuit (10) and the mode detection circuit (11), and the signal from the AFC circuit (10) is fed to the horizontal oscillation circuit (12). ), And the normal-time control signal from the mode detection circuit (11) is supplied to the horizontal oscillation circuit (12). The signal from the horizontal oscillation circuit (12) is supplied to the horizontal deflection circuit (13), and the formed horizontal deflection signal is supplied to the horizontal deflection yoke (14) of the cathode ray tube (6). Further, the signal from the horizontal deflection circuit (13) is supplied to a high voltage generation circuit (15) such as a flyback transformer, and the generated high voltage is supplied to the high voltage terminal (16) of the cathode ray tube (6) and the signal A part is supplied to the AFC circuit (10).

Furthermore, commercial power from the power input (17) is the power circuit (18).
Is supplied to the horizontal deflection circuit (13) in the normal state according to the signal from the mode detection circuit (11). Further, commercial power from the power input (17) is supplied to the other power supply circuit (19), and the formed voltage is supplied to the other circuit.

As a result, a normal video signal is received. On the other hand, when receiving digital or analog three primary color signals of R, G and B (hereinafter referred to as RGB signals) from some personal computers, so-called captain demodulators, telexist demodulators, scan converters and the like. The digital RGB signals supplied to the input terminals (20R) (20G) (20B) and the input terminals (21R) (21G) (21B)
) Is selected by the changeover switch (22) and is supplied to the RGB process circuit (3) and is selected by the changeover signal from the input terminal (4) and the output circuit
Supplied to (5).

Also, the digital sync signal from the input terminal (20S) and the analog sync signal from the input terminal (21S) are selected by the selector switch (23) and supplied to the sync separation circuit (7), and the input terminal (4) Vertical deflection circuit selected by switching signal from (8)
And the AFC circuit (10). Further sync separation circuit
The signal from (7) is supplied to the mode detection circuit (11), a control signal corresponding to the frequency of the horizontal synchronizing signal is formed, and the horizontal oscillation circuit (12), the horizontal deflection circuit (13), and the power supply circuit (1
8) Supplied to.

As a result, an image of a digital or analog RGB signal is received. Furthermore, in the case of performing so-called superimpose image reception in which an RGB signal is displayed by being superimposed on the above-mentioned normal video signal, the switching signal supplied to the input terminal (4) is set to the RGB mode and the input terminal ( 24) Y indicating the position of the superimposed signal
The s signal and the Ym signal indicating the range to be superimposed are supplied to the RGB process circuit (3), and these Y signals
Switching between the video signal and the RGB signal is performed between the s and Ym signals.

As described above, images of various signals are received. Further, in the above-mentioned apparatus, the horizontal deflection system is specifically configured as follows. In FIG. 5, the horizontal sync signal from the sync separation circuit (7) is supplied to the frequency-voltage conversion circuit (FVC) (31) constituting the mode detection circuit (11) via the horizontal sync signal input terminal (7H). As a result, a voltage corresponding to the horizontal frequency is formed. The output voltage of the FVC (31) is supplied to one fixed contact (32b) of the changeover switch (32), and the other fixed contact (32c) of the changeover switch (32) is supplied via the reference voltage source (33). Grounded. In this case, the voltage value of the reference voltage source (33) is applied to the input side of the FVC (31), for example NT.
It is set equal to the voltage value obtained when a horizontal synchronizing signal of SC horizontal frequency of about 15.75 KHz is supplied. In addition, the video / RGB switching signal from the input terminal (4) is supplied to the control terminal of the selector switch (32) through the video RGB switching signal input terminal (4a), and the video / RGB switching signal is supplied to the video signal. Changeover switch to indicate input (32)
The movable contact (32a) of is connected to the other fixed contact (32c), and when the video / RGB switching signal indicates RGB signal input, the movable contact (32a) of the selector switch (32) is connected to one fixed contact (32b). It is made to be connected. The voltage obtained at the movable contact (32a) of the changeover switch (32) is supplied to the voltage controlled oscillator (VCO) (35) constituting the horizontal oscillation circuit (12) through the buffer amplifier (34). This V
The oscillation output of the CO (35) passes through the drive circuit (36) to form the horizontal deflection circuit (13) and the switching transistor (3
Supplied to 7).

The voltage obtained at the movable contact (32a) of the changeover switch (32) constitutes a voltage circuit (18) through a gain control amplifier (38), for example, a YZ type parametric power supply circuit (3).
9) Supplied to. The output voltage of the power supply circuit (39) is fed back to the control amplifier (38) through the voltage dividing circuit (40) to stabilize the output voltage. This output voltage is supplied to the flyback transformer (41).

A switching transistor (37) is connected in series to the flyback transformer (41). In addition, a damper diode (4
2), resonant capacitor (43) and horizontal deflection yoke (14)
And an S-shaped correction capacitor (44) are connected in series.

Further, the horizontal synchronizing signal is supplied to the detection circuit (45) forming the AFC circuit (10), and the signal from the voltage dividing circuit (46) provided in series with the switching transistor (37) is detected by the detection circuit (45). To form an AFC signal.
This signal is supplied to the control terminal of the VCO (35) through the low pass filter (LPE) (47).

Furthermore, a switching circuit (4
Capacitors (49) and (50) are connected through 8). The capacitors (52) and (53) are connected in parallel to the S-shaped correction capacitor (44) through the switch circuit (51).
Further, the voltage from the FVC (31) is supplied to a binary comparison circuit (54) corresponding to the input horizontal frequency voltages of 20 KHz and 30 KHz, for example, 20 KHz or less, 20 to 30 KHz, 30 KHz.
A three-valued comparison output corresponding to each of the above ranges is formed, and in accordance with the comparison output, two switches respectively included in the switch circuits (48) and (51) are both turned off or one of them is turned on. The control is performed so that

As a result, in this horizontal deflection system, the VCO (35)
An oscillation signal that changes to 15 to 34 KHz is formed in synchronization with the input horizontal synchronizing signal to perform horizontal deflection, and the power supply circuit (39) changes it to, for example, 58 to 123 V depending on the water frequency. Voltage is formed, and control is performed so that the amplitude of horizontal deflection is constant. Further, in parallel with the resonance capacitor (43) and the S-shaped correction capacitor (44), capacitors (49) (50) and (52) are provided depending on the horizontal frequency range.
(53) is connected and the characteristics are corrected respectively.

The vertical deflection system in the above apparatus is specifically configured as follows. In FIG. 6, a sync separation circuit (7)
Sawtooth wave oscillator (61) in which the vertical sync signal from the device constitutes the vertical deflection circuit (8) via the vertical sync signal input terminal (7V)
, The capacitor (62) is charged by the current of the current source (63) to form a sawtooth wave. The sawtooth wave is supplied to the comparison circuit (64) to form a three-valued comparison output indicating a predetermined voltage range and below or above the predetermined voltage range, and the comparison output is the control terminal of the up-down counter (UDC) (65). Is supplied to. A vertical synchronizing signal is supplied to the counting terminal of the UDC (65). The count value of the UDC (65) is supplied to the D conversion circuit (DAC) (66), and the current source (63) is controlled by the converted analog value.

Therefore, a sawtooth wave whose peak value (amplitude) is controlled within a predetermined voltage range is taken out from the sawtooth wave oscillator (61) regardless of the frequency of the vertical synchronizing signal. This sawtooth wave is supplied to the vertical deflection yoke (9) through the output circuit (67). Further, a series circuit of a capacitor (68) and a resistor (69) is connected in series with the deflection yoke (9), and a voltage dividing circuit (70) is connected in parallel with the resistor (69). This voltage divider circuit (70)
The divided voltage output of is supplied to the output circuit (67).

As a result, vertical deflection with a constant amplitude is always performed even if the vertical frequency changes. Further, by making one of the resistors constituting the voltage dividing circuit (70) variable, the amplitude of vertical deflection can be arbitrarily controlled.

Further, another set of circuits of the sawtooth wave oscillator (61) to DAC (66) (oscillators (71) to DAC (76)) is provided, and the output value of the DAC (76) of this circuit forms the pin distortion correction signal. While being supplied to the circuit (77), for example, a parabolic signal having a vertical cycle from the midpoint of connection between the deflection yoke (9) and the capacitor (68) is supplied to the forming circuit (77) to form a pin distortion correction signal. It This signal is supplied to the pin distortion correction circuit.

Thus, in the above-mentioned device, horizontal / vertical deflection necessary for various horizontal / vertical frequencies is performed and various signals are received.

[Problems to be solved by the invention]

Conventionally, by the so-called scanning speed modulation that speeds up or slows down the horizontal scanning speed of the electron beam at the boundary between light and dark of the image,
The outline of an image is made clear. In this scanning velocity modulation, a scanning velocity modulation signal as shown in FIG.
Apply to the terminal for scanning speed modulation of the 4th grid of (6),
The scanning speed is varied by electrostatically deflecting the electron beam according to the scanning speed modulation amount, as shown in FIG. 7A.

However, since the horizontal frequency of the input signal is not constant in the above-mentioned multi-scan television receiver, the scanning speed modulation as shown in FIG. 8B, which is obtained by second-order differentiation of the image signal when the horizontal frequency becomes high, is obtained. The peak-to-peak value of the scanning speed modulation amount of the signal becomes abnormally large, and when the scanning speed is varied by electrostatically deflecting the electron beam by this scanning speed modulation amount, the electron beam becomes as shown in FIG. 8A. It became clear that it goes backwards at the boundary between the light and dark of the image.

In view of this point, the present invention proposes a device capable of favorably modulating the scanning speed of an electron beam even for input signals having different horizontal frequencies.

[Means for solving problems]

The multi-scanning television receiver of the present invention, for example, as shown in FIG. 1, detects the horizontal frequency of an input signal and converts it into a voltage, adds this voltage to a horizontal deflection circuit (13), and then this horizontal deflection circuit (13). In the multi-scanning television receiver that switches the horizontal deflection frequency of (1) to receive input signals of different horizontal frequencies, the first differentiating circuit (8
0), a noise elimination circuit (81) to which the output signal of the first differentiating circuit (80) is supplied and which eliminates a signal having a constant amplitude or less, and an output signal of the noise elimination circuit (81), and AGC circuit (82) incorporating the second differentiation circuit and this AGC circuit
The detection circuit (83) for detecting the peak-to-peak value of the output signal of (82), and the frequency discriminator (84) to which the horizontal synchronization signal from the synchronization separation circuit (7) is supplied are included in the AGC circuit. (82)
Is supplied to the cathode ray tube (6) as a scanning speed modulation signal, the gain of the AGC circuit (82) is controlled by the detection output signal of the detection circuit (83), and the frequency discriminator (84) is also controlled. The time constant of the AGC circuit (82) is controlled by the output signal of (1) to control the scanning speed modulation amount.

[Action]

According to such a configuration, the horizontal deflection frequency of the horizontal deflection circuit (13) that is switched according to the horizontal frequency of the input signal is detected, the scanning speed modulation amount is controlled by this detection output, and the input signals with different horizontal frequencies are detected. Also, the scanning speed modulation of the electron beam is favorably performed.

〔Example〕

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

In this example, the RGB process circuit as shown in FIG.
The luminance signal of (3) is supplied to the first differentiating circuit (80), and the differential output of the first differentiating circuit (80) is passed through a noise removing circuit (81) through which a signal having a fixed amplitude or less is removed. The AGC circuit (82) incorporating the second differentiation circuit is supplied to the AGC circuit (82).
The output signal of the circuit (82) is supplied as a scanning speed modulation signal to the scanning speed modulation terminal G of the fourth grid of the cathode ray tube (6) and the peak-to-peak value detection circuit (83) of the scanning speed modulation amount. The detection output of the detection circuit (83) is supplied to the gain control terminal of the AGC circuit (82). In this case, AGC
The circuit (82) is controlled by the detection output of the detection circuit (83) so that the peak-to-peak value of the scanning speed modulation amount becomes a predetermined value.

On the other hand, the horizontal sync signal from the sync separation circuit (7) is supplied to the frequency discriminator (84), and the output signal of the frequency discriminator (84) is supplied to the time constant control terminal of the AGC circuit (82). In this case, the time constant of the AGC circuit (82) is the frequency discriminator (8
4) Increase in proportion to the input frequency.

The other horizontal deflection system, vertical deflection system, etc. are constructed in the same manner as the multi-scanning television receiver shown in FIGS.

According to such a configuration, when a video signal having a horizontal frequency of about 15.734 KHz is input to the input terminal (1), the video signal is transmitted via the video process circuit (2) to the RGB process circuit (3).
Is supplied to the cathode ray tube (6) through the output circuit (5) and the luminance signal of the RGB process circuit (3) is supplied to the first differentiation circuit (8).
0) and the noise removal circuit (81) through the AGC circuit (82)
Is supplied to. At this time, about 15 from the sync separation circuit (7).
The time constant of the AGC circuit (82) is set to the predetermined value corresponding to the horizontal deflection frequency of about 15.734 KHz by the output signal of the frequency discriminator (84) obtained by discriminating the horizontal synchronization signal of 734 KHz. The scanning speed modulation signal as shown in FIG. 2B, which has been subjected to the second derivative at (82) and whose peak-to-peak value has been set to a predetermined value by the detection output of the detection circuit (83), is the fourth signal of the cathode ray tube (6). It is applied to the terminal G for scanning speed modulation of the grid. Therefore, the electron beam is electrostatically deflected by the scanning velocity modulation signal having the predetermined scanning velocity modulation amount as shown in FIG. 2B, and the scanning velocity modulation of the electron beam is satisfactorily performed as shown in FIG. 2A.

Also, when a video signal with a relatively high horizontal frequency of, for example, about 31.468 KHz is input to the input terminal (1), the video signal passes through the video process circuit (2) to the RGB process circuit (3).
Is supplied to the cathode ray tube (6) through the output circuit (5) and the luminance signal of the RGB process circuit (3) is supplied to the first differentiation circuit (8).
0) and the noise removal circuit (81) through the AGC circuit (82)
Is supplied to. At this time, about 31 from the sync separation circuit (7).
The time constant of the AGC circuit (82) is set to a predetermined value corresponding to the horizontal deflection frequency of about 31.468 KHz by the output signal of the frequency discriminator (84) obtained by frequency discriminating the horizontal synchronization signal of 468 KHz. The scanning speed modulation signal as shown in FIG. 3B, which has been subjected to the second derivative at (82) and the peak-to-peak value has been made a predetermined value by the detection output of the detection circuit (83), is output to the fourth section of the cathode ray tube (6). It is applied to the terminal G for scanning speed modulation of the grid. Therefore, the electron beam is electrostatically deflected by the scanning velocity modulation signal according to the predetermined scanning velocity modulation amount as shown in FIG. 3B, and the scanning velocity modulation of the electron beam is satisfactorily performed as shown in FIG. 3A.

As described above, according to this example, the horizontal frequency of the input signal is detected and converted into a voltage, and this voltage is supplied to the horizontal deflection circuit (13).
In addition, the horizontal deflection frequency is detected in a multi-scanning television receiver that switches the horizontal deflection frequency of this horizontal deflection circuit (13) to receive input signals of different horizontal frequencies, and the scanning output modulation amount is detected by this detection output. Therefore, there is an advantage that the scanning speed modulation of the electron beam can be favorably performed even for input signals having different horizontal frequencies.

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

〔The invention's effect〕

According to the multi-scanning television receiver of the present invention, there is an advantage that the scanning velocity modulation of the electron beam can be favorably performed even for input signals having different horizontal frequencies, and a favorable image with clear contour can be obtained. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a main part of a multi-scanning television receiver of the present invention, and FIGS.
4 is a block diagram showing an example of a multi-scanning television receiver, FIG. 5 is a block diagram showing the horizontal deflection system of FIG. 4 extracted, and FIG. The vertical deflection system of FIG. 4 is extracted and shown in FIG. 7, FIG. 7 and FIG.
The figure is a diagram for explaining the husband and husband scanning velocity modulation. (3) is an RGB process circuit, (6) is a cathode ray tube, (7) is a sync separation circuit, (80) is a first differentiation circuit, (81) is a noise elimination circuit, (82) is an AGC circuit, and (83) ) Is a detection circuit, (84)
Is a frequency discriminator, and G is a terminal for scanning velocity modulation of the fourth grid of the cathode ray tube.

Claims (1)

[Claims] 1. A multi-unit for receiving an input signal of a different horizontal frequency by detecting a horizontal frequency of an input signal, converting the voltage into a voltage, applying the voltage to a horizontal deflection circuit, and switching the horizontal deflection frequency of the horizontal deflection circuit. In a scanning television receiver, a first differentiating circuit to which a luminance signal is supplied, a noise removing circuit to which an output signal of the first differentiating circuit is supplied and which removes a signal having a constant amplitude or less, and the noise removing circuit. Output signal of the AGC circuit and a second differentiating circuit incorporated therein, a detection circuit for detecting a peak-to-peak value of the output signal of the AGC circuit, and a horizontal synchronization signal from a synchronization separation circuit. A frequency discriminator, the output signal of the AGC circuit is supplied to the cathode ray tube as a scanning speed modulation signal, and the gain of the AGC circuit is controlled by the detection output signal of the detection circuit. Multi scan type television receiver is characterized in that so as to control the scanning speed modulation amount constant control to when the AGC circuit by an output signal of the frequency discriminator as well as.