JPH0584700B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to ordinary television broadcast reception,
The present invention relates to a video signal receiving device capable of selectively receiving video signals from video tape recorders, video disk players, satellite broadcasting, personal computers, so-called captain demodulators, teletext demodulators, and the like.

[Conventional technology]

First, in addition to the reception of ordinary television broadcasts, it was made possible to switch and receive video signals from video tape recorders, video disk players, satellite broadcasts, personal computers, so-called captain demodulators, teletext demodulators, etc. (Fig. 2). A television receiver as shown in the following has been proposed.

In Fig. 2, when receiving a normal composite video signal from a normal television broadcast reception tuner, video tape recorder, video disc player, satellite broadcast reception tuner, or some personal computers, input terminal 1
The composite video signal supplied to the video processing circuit 2 is supplied to the RGB processing circuit 3 through the video processing circuit 2 to form three primary color signals of a red signal R, a green signal G and a blue signal B. Further, the video/RGB switching signal supplied to the input terminal 4 is supplied to the process circuit 3, whereby the three primary color signals from the selected video signal are supplied to the color cathode ray tube 6 through the output circuit 5.

Further, the composite video signal from the input terminal 1 is supplied to a synchronization separation circuit 7, and vertical and horizontal synchronization signals are separated. Furthermore, the switching signal from the input terminal 4 is supplied to the separation circuit 7, whereby the vertical synchronizing signal from the selected video signal is supplied to the vertical deflection circuit 8, and the vertical deflection signal thus formed is transmitted to the color cathode ray tube 6. vertical deflection yoke 9. Further, the horizontal synchronizing signal from the video signal selected by the separation circuit 7 is supplied to the AFC circuit 10.
A signal from the mode detection circuit 12 is supplied to the horizontal oscillation circuit 11, and a normal control signal from the mode detection circuit 12 is supplied to the horizontal oscillation circuit 11. The signal from the horizontal oscillation circuit 11 is then supplied to the horizontal deflection circuit 13, and the formed horizontal deflection signal is supplied to the horizontal deflection yoke 14 of the color cathode ray tube 6. Furthermore, 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 applied to the high voltage terminal 16 of the color cathode ray tube 6.
A part of the signal is supplied to AFC circuit 1.
0.

Further, commercial power from the power input terminal 17 is supplied to the power supply circuit 18, and a normal voltage according to the signal from the mode detection circuit 12 is supplied to the horizontal deflection circuit 13. Further, the commercial power from the power input terminal 17 is supplied to another power supply circuit 19, and the generated voltage is supplied to the other circuit.

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

Further, the synchronization signal of the digital R, G, and B signals from the input terminal 20S and the synchronization signal of the analog R, G, and B signals from the input terminal 21S are selected by the changeover switch 23 and supplied to the synchronization separation circuit 7. , selected by a switching signal from the input terminal 4 and supplied to the vertical deflection circuit 8 and the AFC circuit 10. Furthermore, the signal from the separation circuit 7 is transmitted to the mode detection circuit 12.
A control signal corresponding to the frequency of the horizontal synchronizing signal is formed and supplied to the horizontal oscillation circuit 11, the horizontal deflection circuit 13, and the power supply circuit 18.

This allows digital or analog R,G
The three primary color signals of the B signal and the B signal are received. Furthermore, when performing so-called superimposed image reception in which R, G, and B signals are displayed superimposed on the above-mentioned normal composite video signal, the switching signal supplied to the input terminal 4 is set to RGB mode, and _{The Ys} signal indicating the position of the superimposed signal and the Yn signal indicating the superimposed range supplied to the input terminal 24 are input to _the RGB process circuit 3.
Switching between the composite video signal and R, G, and B signals is performed between these Y _s and Y _n signals.

Various signals are received in the manner described above. Further, in the above-mentioned apparatus, the horizontal deflection system is specifically constructed as shown in FIG. In FIG. 3, the horizontal synchronization signal from the separation circuit 7 is supplied to the frequency-voltage conversion circuit 31 forming the mode detection circuit 12 via the horizontal synchronization signal input terminal 7H, and a voltage according to the horizontal frequency is formed. . This voltage is supplied to a voltage controlled variable frequency oscillator (VCO) 34 constituting the horizontal oscillation circuit 11 through a limiter circuit 32 that determines the lower limit and a buffer amplifier 33. The oscillation output of this VCO 34 is the drive circuit 35
The signal is supplied to the switching transistor 36 constituting the horizontal deflection circuit 13 through the signal.

In addition, a limiter circuit 37 and a control amplifier 38 that determine the upper and lower limits of the voltage from the frequency-voltage conversion circuit 31
The signal is supplied to, for example, a YZ type parametric power supply circuit 39 forming the power supply circuit 18 through the power supply circuit 18 . The output voltage of this power supply circuit 39 is fed back to the control amplifier 38 through the voltage dividing circuit 40, and the output voltage is stabilized. This output voltage is
1.

A horizontal output transistor 36 is connected in series to this flyback transformer 41. In addition, a damper diode 42 is connected in parallel to this transistor 36,
A series circuit of the resonance capacitor 43, the horizontal deflection yoke 14, and the S-shaped correction capacitor 44 is connected.

Further, the horizontal synchronizing signal is supplied to the detection circuit 45 constituting the AFC circuit 10, and a signal from the voltage dividing circuit 46 provided in series with the transistor 36 is supplied to the detection circuit 45 to form an AFC signal. This signal is passed through low pass filter (LPF) 4
7 to the control terminal of the VCO 34.

Furthermore, capacitors 49 and 50 are connected in parallel to the resonance capacitor 43 through a switch circuit 48. Further, capacitors 52 and 53 are connected in parallel to the S-shaped correction capacitor 44 through a switch circuit 51. In addition, the voltage from the frequency-voltage conversion circuit 31 is, for example, 20kHz of input horizontal frequency and
Comparison circuit 54 for binary comparison corresponding to 30kHz voltage
A comparison output corresponding to each range of 20kHz or less, 20 to 30kHz, and 30kHz or more is formed, and depending on this comparison output, the two switches built in each of the switch circuits 48 and 51 are turned off or turned off. Control is performed so that one of the two is turned on.

As a result, in this horizontal deflection system,
15 to 15 in synchronization with the input horizontal synchronization signal at VCO34
An oscillation signal that changes to 34 kHz is formed to perform horizontal deflection, and at the same time, a voltage that changes from 58 to 123 volts depending on the horizontal frequency is generated in the power supply circuit 39, so that the amplitude of the horizontal deflection is constant. Control is performed to ensure that In addition, the resonance capacitor 43
and in parallel with the S-correction capacitor 44, capacitors 49, 50 and 5 depending on the horizontal frequency range.
2 and 53 are connected, and the characteristics of each are corrected.

Further, in the above-mentioned apparatus, the vertical deflection system is specifically constructed as shown in FIG. In FIG. 4, a vertical synchronizing signal from a separation circuit 7 is supplied to a sawtooth wave oscillator 61 constituting a vertical deflection circuit 8 via a vertical synchronizing signal input terminal 7V, and for example, a capacitor 62 is charged with a current from a current source 63. The discharge forms a sawtooth wave. This sawtooth wave is supplied to a binary comparison circuit 64 to form a comparison output indicating a predetermined voltage range and below or above it, and this comparison output is supplied to a control terminal of an up-down counter (UDC) 65. . A vertical synchronizing signal is supplied to the counting terminal of this UDC 65. This UDC65 count value converts the digital signal to an analog signal.
The analog value is supplied to a DA conversion circuit (DAC) 66, and a 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 extracted from the sawtooth wave oscillator 61 regardless of the frequency of the vertical synchronization signal. This sawtooth wave is supplied to the vertical deflection yoke 9 through the output amplification circuit 67. Furthermore, this vertical deflection yoke 9
A series circuit of a capacitor 68 and a resistor 69 is connected in series to the resistor 69, and a voltage dividing circuit 7 is connected in parallel to this resistor 69.
0 is connected. The divided voltage output of this voltage dividing circuit 70 is supplied to the negative feedback terminal of the output amplifier circuit 67.

This ensures that vertical deflection always has a constant amplitude even if the vertical frequency changes. Furthermore, the voltage dividing circuit 70
By making one of the resistors variable, the amplitude of the vertical deflection can be arbitrarily controlled.

Furthermore, another set of circuits (oscillators 71 to DAC76) including an oscillator 61 to DAC 66 is provided, and the output value of the DAC 76 of this circuit is supplied to a pin distortion correction signal forming circuit 77. A vertically periodic parabolic signal from the connection midpoint of is supplied to the forming circuit 77,
A pin distortion correction signal is formed. This signal is supplied to the pin distortion correction circuit.

Thus, in the device described above, the necessary horizontal and vertical deflections are performed according to different horizontal and vertical frequencies, as well as the reception of various signals.

[Problem that the invention seeks to solve]

By the way, in the composite video signal of television broadcasting, where Z _V is the vertical period of this composite video signal and Z _D is the time displayed on the video screen of the actual color cathode ray tube 6, Z _D / It is determined that Z _V = 0.87, but for other video signals such as video signals from personal computers, captain demodulators, teletext demodulators, scan converters, etc., this Z _D /Z _V may be 75% depending on the type. Since the variation was around 90%, there was an inconvenience that depending on the selected video signal, the top and bottom of the video screen would be hidden.

In view of these points, the present invention is capable of displaying a video signal whose display range on the video screen is determined within that range, and even when receiving a video signal whose display range on the video screen is not determined. The purpose is to obtain the optimal screen.

[Means for solving problems]

In the present invention, in a video signal receiving device capable of receiving a plurality of types of video signals, two or more vertical effective screen adjustment volumes 78, 79 or more are provided,
These two or more vertical effective screen adjustment volume 7
One of 8 and 79 is made adjustable by the user, and the other 78 is a semi-fixed resistor, and the mode in which the regulators 78 and 79 are enabled is set to one of these multiple types of video signals. It is designed so that it can be selected depending on the video signal to be received.

[Operation] According to the present invention, when receiving a video signal for which the display range of the video screen is determined, the vertical effective screen adjustment volume 78 in which the vertical effective screen is adjusted and fixed in advance is selected to adjust the optimal video screen. When receiving a video signal for which the display range of the video screen is not determined, an optimum video screen is obtained by selecting a vertical effective screen adjustment volume 79 that can be adjusted by the user and adjusting it.

〔Example〕

Hereinafter, one embodiment of the video signal receiving apparatus of the present invention will be described with reference to FIG. In FIG. 1, parts corresponding to those in FIGS. 2 and 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, a vertical deflection system is constructed as shown in FIG. 1 in a television receiver as shown in FIG.

That is, in FIG. 1, the output terminal of the vertical output amplification circuit 67 in FIG. 4 is connected to the vertical deflection yoke 9, S
It is grounded through a series circuit of a capacitor 68 for character correction and a resistor 69 for current detection. The connecting point of resistors 80 and 82 is connected to the negative feedback terminal of the output amplification circuit 67 through a circuit, and the connection point of the resistors 80 and 82 is connected to one of the changeover switches 81 through a semi-fixed resistor that constitutes the vertical effective screen adjustment volume 78. Contact 8
1L, and the connecting point of the resistors 80 and 82 is connected to the other fixed contact 81M of the changeover switch 81 via a variable resistor constituting the vertical effective screen adjustment volume 79.
The movable contact 81a is grounded. In this case, the semi-fixed resistor of the vertical effective screen adjustment volume 78 is adjusted and fixed in advance to the optimum vertical screen size when receiving the composite video signal of the television broadcast signal, and the vertical effective screen adjustment volume 78 is adjusted and fixed in advance. A knob is provided so that the user can adjust the movable element 79. In addition, in this example, this changeover switch 81
The movable contact 81a is controlled by a video/RGB switching signal supplied to the video/RGB switching signal input terminal 4. In this case, when receiving composite video signals such as those from television broadcasting, the vertical display range is determined, so this movable contact 81a is connected to one fixed contact 81L, and a vertical effective screen adjustment volume 78 made of a semi-fixed resistor is connected. This movable Connect the contact 81a to the other fixed contact 81M
The vertical effective screen adjustment volume 79, which can be adjusted by the user, becomes effective.

Further, the connection point between the vertical deflection yoke 9 and the capacitor 68 is connected to the negative feedback terminal of the output amplifier circuit 67 via a series circuit of resistors 84 and 85, and the connection point between the resistors 84 and 85 is connected to the resistor 86 and the capacitor. It is grounded through a series circuit of 87. The rest of the structure is the same as that shown in FIG.

In this example, the regulators 78 and 79 that attenuate the negative feedback current flowing through the vertical deflection yoke 9 are inserted into the negative feedback circuit.
By adjusting the resistance values of 8 and 79, the current flowing through the vertical deflection yoke 9 can be adjusted, and the vertical effective screen of the color cathode ray tube 6 can be adjusted.

In this case, in this example, when receiving a composite video signal of television broadcasting, the movable contact 81a of the changeover switch 81 is connected to one fixed contact 81L, so in this case, the vertical effective screen adjustment is made of a semi-fixed resistor. The control volume 78 becomes effective, and an optimal video screen can be obtained without requiring any adjustment. Furthermore, when receiving the three primary color signals of R, G, and B signals from a personal computer or the like, the movable contact 81a of the changeover switch 81 is connected to the other fixed contact 81M, so that the vertical effective screen adjustment volume 79 that can be adjusted by the user is Even if the range of the display screen varies, the vertical effective screen is adjusted by the user adjusting the vertical effective screen adjustment volume 79, thereby making it possible to obtain an optimal video screen.

In the above embodiment, two volumes 78 and 79 are used, but it is also possible to provide two or more volumes corresponding to the range of the display screen of the video signal that receives the video signal. Of course.
Further, in the above embodiment, in order to adjust the effective screen in the vertical direction of the color cathode ray tube 6, the adjusters 78 and 79 for adjusting the negative feedback current are inserted into the negative feedback circuit for the current flowing through the vertical deflection yoke 9. Instead, the resistor for detecting the current flowing through the vertical deflection yoke 9 may be configured with two or more resistors, and the resistors may be switched depending on the received video signal, or the vertical sawtooth wave oscillator 61 A circuit for changing the oscillation level of the sawtooth wave oscillator 61 and the output amplifier circuit 67 may be configured such that two or more volumes are provided and the volume is switched depending on the received video signal. It is easy to understand that the same effect as described above can be obtained even if an attenuator is constructed using two or more volumes and these are switched and used depending on the received video signal. Furthermore, 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 present invention, when receiving a video signal for which the display range of the video screen has been determined, the vertical effective screen is adjusted in advance, and the fixed vertical effective screen adjustment volume 78 is selected so that the user can adjust the optimal video screen. can be obtained without adjustment. Further, when receiving a video signal for which the display range of the video screen is not determined, the vertical effective screen adjustment volume 79, which can be adjusted by the user, is selected, and by adjusting this, there is an advantage that an optimum video screen can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the essential parts of an embodiment of the video signal receiving device of the present invention, FIG. 2 is a block diagram showing an example of a television receiver, and FIGS.
FIG. 2 is a configuration diagram showing an example of a main part of the figure. 1 is a composite video signal input terminal, 3 is an RGB process circuit, 5 is an output circuit, 6 is a color cathode ray tube, 8
9 is a vertical deflection circuit, 9 is a vertical deflection yoke, 13 is a horizontal deflection circuit, 14 is a horizontal deflection yoke, 20R, 2
0G and 20B are digital R, G and B signal input terminals respectively, 21R, 21G and 21B are analog R, G and B signal input terminals respectively, 69, 80 and 82 are resistors respectively, 78 and 79 are vertical effective screens respectively The adjustment volume 81 is a changeover switch.

Claims (1)

[Claims] 1. In a video signal receiving device capable of receiving multiple types of video signals, two or more vertical effective screen adjustment volumes are provided,
One of the two or more vertical effective screen adjustment volumes is adjustable by a user, and the other is a semi-fixed resistor, so that each of the two or more vertical effective screen adjustment volumes is enabled. A video signal receiving device characterized in that a mode can be selected depending on a video signal to be received from among the plurality of types of video signals.