JPS6165667A - Multi-scanning type image receiver - Google Patents

Abstract

PURPOSE:To form a blanking signal at a fixed ratio for a horizontal period constantly without depending upon a change of a horizontal frequency by comparing a parabolic wave signal related to a horizontal scanning with a prescribed level for the amplitude and forming a blanking signal. CONSTITUTION:A parabolic wave signal related to a horizontal scanning of a terminal 101 is supplied to a comparing part 103 at a prescribed level by removing a direct current component at a voltage dividing and direct current removing circuit 102. On the other hand, by using the value, in which the maximum amplitude of of the above-mentioned parabolic wave signal is rectified at a rectifying circuit 104, a comparing level of the comparing circuit 103 is set at a level control circuit 105, and by using an output signal 108 of the above- mentioned comparing circuit, blanking of a horizontal fly-back line of a video signal is executed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to not only normal television broadcast reception but also to scanning? fM
The present invention relates to a multi-scanning type receiver capable of receiving video signals having different horizontal frequencies from a converter or the like that doubles the horizontal frequency.

[Conventional technology]

For example, in an NTSC television signal,
Frequency is approximately 60Hz, horizontal frequency is approximately 15.75K
Images are formed at Hz. In response, 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 that will be output will have a vertical frequency of approximately 60Hz.
On the other hand, the horizontal frequency is approximately 31.5kHzK.

In addition, there are computer output signals for so-called high-resolution display that have a horizontal frequency of about 24 kHz. Furthermore, in so-called high-definition televisions, the horizontal frequency is expected to be approximately 33.75 kHz.

A multi-scanning receiver has been proposed that allows a single device to receive signals with different horizontal frequencies.

By the way, in conventional television receivers, a so-called horizontal blanking signal for erasing the video signal during the horizontal retrace period is formed with a predetermined time width between the horizontal synchronizing signals.

However, in the above-mentioned device, for example, if the number of foot blue edges mentioned above is set to 2,
If a doubled conversion signal is provided.

The ratio of the scanning period to the retrace period of such a converted signal is made equal to that of the original television signal. In other words, as shown in Figure 7, the horizontal period of the 5KNTSC television signal is 63.5.
In μ, the scanning period is 50# flag, and the retrace period is 13.5μ.
In the case of an island, the horizontal period of the signal doubled is 31.
With a reduction of 75μ, the scanning period is approximately 25μ.

The return period is 6.75 μm.

For this reason, like the conventional television receiver mentioned above.

If a configuration is adopted in which blanking of the video signal is performed at a predetermined time width between horizontal synchronizations, for example, when the blanking period is determined based on the conversion signal.

When receiving the original TV signal, proper blanking cannot be performed outside the left and right effective screens, and the electron beam hits the side of the cathode ray tube, generating unnecessary secondary electrons and impairing the quality of the display screen. There is a risk.

Conversely, if the blanking period is determined based on the original television signal, the left and right effective l1i
A part of the II city is blanked, making it impossible to perform a complete view.

[Problem that the invention seeks to solve]

A multi-scanning receiver as described above has been proposed. However, in this device, if horizontal blanking is performed using the same configuration as used in conventional television receivers, appropriate blanking cannot be performed at all horizontal frequencies.

There was a problem that the display screen could be damaged depending on the frequency.

[Means for solving problems]

The present invention provides parabolic wave signals (101
) is supplied to the comparator circuit (103) at a predetermined level (102) by removing the DC component, and the comparison level of the comparator circuit is set using the value obtained by rectifying (104) the maximum amplitude of the parabolic wave signal. Setting (105) 1. This is a multi-scanning receiver characterized in that the output signal (10g) of the comparison circuit is used to blank the horizontal return of the video signal.

[Effect]

According to the above-mentioned system, a parabolic wave signal (101) related to the horizontal movement f is compared at a predetermined level (105) with respect to its amplitude (104) (103) l, and a blanking signal is formed (108). Therefore, the blanking signal can always be formed at a constant ratio to the wateron period, regardless of changes in the horizontal frequency.

〔Example〕

First, we will explain the multi-scanning receiver proposed by the applicant.

The overall block diagram is shown in the fourth button. In this figure, a normal television broadcast chainer or video tape recorder,
When receiving a normal video signal from a video disc player, satellite broadcast channel, some personal combiators, etc., the video signal supplied to the input terminal The video/RGB switching signal supplied to the input terminal (4) is supplied to the process circuit (3), thereby forming the three primary color signals from the selected video signal. The three primary color signals are supplied to the cathode capillary (6) through the output circuit (51).

In addition, the video signal from the input terminal il+ is transferred to the sync separation circuit (
71k is supplied, and vertical and horizontal synchronization signals are separated.

Furthermore, the switching signal from the input terminal (41) is sent to the separation circuit (7).
A vertical synchronizing signal from a video signal selected by this signal is supplied to a vertical deflection circuit (8), and the vertical deflection signal thus formed is sent to a vertical deflection yoke (61) of a cathode ray tube (61).
91. Further, the horizontal synchronizing signal from the video signal selected by the separation circuit (7) is supplied to the AFC circuit alK, and the signal from this AFC circuit αG is supplied to the horizontal oscillation circuit fu.
At the same time, the normal control signal from the mode detection circuit C'a is supplied to the oscillation circuit (IIIc).The signal from this oscillation circuit (111) is then supplied to the horizontal deflection circuit (IIIc).
13, and the formed horizontal deflection signal is sent to the cathode ray tube (
61 horizontal deflection yokes α4i are supplied.

Further, the signal from the deflection circuit 031 is supplied to a high voltage generating circuit a9' such as a flyback transformer, and the generated high voltage is supplied to the high voltage terminal a5VC of the cathode ray tube (61), and part of the signal is supplied to the high voltage terminal a5VC of the cathode ray tube (61). supplied to

Further, commercial power from the Vc power input a is supplied to the power supply circuit a&, and a normal voltage according to the signal from the detection circuit Q2 is supplied to the horizontal deflection circuit 1131. In addition, the commercial power from the source input system is supplied to another power supply circuit a9, and the generated voltage is supplied to other circuits.

This allows normal video signal reception. On the other hand, when receiving digital or analog RGB signals from some personal computers, so-called captain demodulators, teletext demodulators, or scan converters, input terminals (20R) (20GM20B
) and the digital RGB signals supplied to the input terminal (21
Analog RG supplied to R) (21G) (21B)
The B signal is selected by the changeover switch and supplied to the RGB process circuit (3)K, and selected by the changeover signal from the input terminal (4) and supplied to the output circuit 151 VC.

Further, the digital synchronization signal from the input terminal (208) and the analog synchronization signal from the input terminal (218) are selected by the changeover switch (c) and supplied to the synchronization separation circuit (7), and the input terminal (4) (on the vertical deflection circuit) and is supplied to the FC@path aα. Furthermore, the signal from the separation circuit (7) is supplied to the mode detection circuit Q3, and a control signal according to the frequency of the horizontal synchronization signal is formed, and the horizontal oscillation circuit au, the horizontal deflection circuit a3, and the power supply circuit Q
81.

As a result, digital or analog RGB signals are received. Furthermore, when performing so-called superimposed image reception in which the above-mentioned normal video signal Kfi is multiplied to display an RGB signal, the switching signal supplied to the input terminal +41ic is set to RGB mode, and the input terminal r241IIC is supplied to the Ys multiplied signal indicating the position of the signal to be superimposed and the Ya scratch signal indicating the range to be superimposed. and R.G.
Switching with the B signal, etc. is performed.

Various signals are received in the manner described above.

In the above-mentioned apparatus, the horizontal deflection system is specifically constructed as follows. In Figure 5, one separation circuit (7
) is supplied to a frequency-voltage conversion circuit (FVC) C311 that constitutes the mode detection circuit Q21 to form a voltage according to the horizontal frequency. This voltage is supplied to a voltage controlled oscillator (VCO) 64) which constitutes a horizontal oscillation circuit an through a limiter circuit 113 which determines the lower limit and a buffer (B) amplifier field. This vCO (ro)
The oscillation output is supplied to the switching transistor (161) constituting the °C horizontal deflection circuit a3 through the drive circuit (2).

Further, the voltage from the FVCC 11l is supplied to, for example, a Y-2 type parametric power supply circuit 01 constituting the power supply circuit aa through a limiter circuit C371 that determines upper and lower limits and a gain control (GC) amplifier (to). The output voltage of the power supply circuit 0 is fed back to the amplifier W through the voltage dividing circuit 0 to stabilize the output voltage. This output voltage is supplied to the flyback transformer I.

A transistor (
) is connected. Further, a series circuit consisting of a damper diode member 2, a resonance capacitor IA3, a horizontal deflection yoke α center, and a figure-8 correction capacitor G14 is connected in parallel with this transistor (to) k.

In addition, a horizontal synchronizing signal is supplied to the detection circuit forming the AFC circuit aα, and a signal from the voltage dividing circuit connected in series to the AFC circuit aα is supplied to the detection circuit ta. A signal is formed. This signal is supplied to the control terminal of the VCO (to) through a low pass filter (LPP) (4?).

Furthermore, a capacitor decoy is connected in parallel to the resonant capacitor through a switch circuit (to). Further, a capacitor 63a1 is connected in parallel to the figure-8 correction capacitor through a switch circuit 611. Also, the voltage from FVCaυ is, for example, at the input horizontal frequency of 20kHz and 30kHz.
The voltage is supplied to a comparison circuit 64 for binary comparison corresponding to the voltage of z, and comparison outputs corresponding to each range of 20 kHz or less, 20 to 30 kHz, and 30 kHz or more are formed. Control is performed so that both of the two built-in switches are turned off or one of them is turned on.

Therefore, in this horizontal deflection system, VCO (b) K [15 to 34 kHz in synchronization with the input horizontal synchronizing signal
An oscillation signal that is varied by K is formed to perform horizontal deflection, and a voltage that is varied from 58 to 123 volts depending on the horizontal frequency is formed in the 14f source circuit (to) K, so that the amplitude of the horizontal deflection is varied. Control is performed to keep it constant.

In addition, the resonant capacitor +41 and the S-shaped sleeve positive capacitor (4
In parallel with 41, depending on the horizontal frequency range, a capacitor f
415G and 54■ are connected, and the characteristics of each are corrected.

Further, in the above-mentioned device, the vertical deflection system is specifically constructed as follows. In FIG. 6, a vertical synchronizing signal from a separation circuit (7) is supplied to a sawtooth wave oscillator 611 constituting a vertical deflection circuit (81). This sawtooth wave is supplied to a binary comparison circuit (product) to form a comparison output indicating a predetermined voltage range and below or above, and this comparison output is sent to an up-down counter (UDC).
(to) is supplied to the control terminal. A vertical synchronizing signal is supplied to the counting terminal of this UDC. The count value of each UDCi is supplied to a DA conversion circuit (DAC) IQ, and the current source is controlled by the changed analog value.

Therefore, a sawtooth wave whose peak value (amplitude) is controlled within a predetermined voltage range is extracted from the oscillator regardless of the frequency IBL of the vertical synchronizing signal. This sawtooth wave is supplied to the vertical deflection yoke (9) through the front of the output circuit.

Furthermore, a series circuit of a capacitor and a resistor is connected in series to this deflection yoke (91), and a voltage dividing circuit σα is connected to this resistor II K series.This voltage dividing circuit σ(2)
The divided voltage output is supplied to the output circuit 6'OK.

This ensures that vertical deflection always has a constant amplitude even if the vertical frequency changes. Furthermore, by making the 10,000 resistors making up the voltage dividing circuit aα variable, the amplitude of the vertical deflection can be arbitrarily controlled.

Furthermore, another set of oscillator ευ~DAC− circuits (oscillator συ~DACσ [9) is provided, and the DACσe of this circuit is
When the output value of is supplied to the bin distortion correction signal forming circuit σDK, for example, a parabolic signal with a vertical period from the connection midpoint between the deflection yoke (9) and the capacitor is formed by the forming circuit σ7)K.
applied to form a bin distortion correction signal. This signal is supplied to the bin distortion correction circuit.

In this way, in the eVC described above, the necessary horizontal and vertical deflections are performed according to various different horizontal and vertical frequencies, and the signals of each frequency are received.

In this device, the following circuit is provided in the row 5 portion for forming a blanking signal.

In FIG. 1, an input terminal (101) is supplied with a horizontally periodic parabolic wave from, for example, the connection midpoint between the horizontal deflection yoke +141 and the S-shaped correction capacitor @4.

This parabolic wave is supplied to comparison circuit # (103) K through a voltage division and DC removal circuit (102). Further, the parabolic wave from the input terminal (101) is supplied to a rectifier circuit (104) that rectifies peak-to-peak, and this rectified value is supplied to a level control circuit (105) to form a predetermined level. This level value is supplied to an adder circuit (106). Further, the signal from the voltage dividing and direct current removal circuit (102) is supplied to a low pass filter (lO7) to form an integrally delayed signal, and this signal is sent to the adder circuit (106).
). The signal from this adder circuit (106) is supplied to a comparator circuit (103), and the comparison output is taken out from an output terminal (108).

Therefore, in this circuit, when a parabolic wave such as the human song 111Ia in FIG. 2 is supplied, when this signal is rectified, a level as shown by the broken line is formed. From this level b, a controlled level such as 1lIIC is formed, and an integrally delayed signal such as this level cK curve d is added. Then, the signal of curve d and the parabolic wave of curve a are compared, and the output terminal (10
8), a pulse signal corresponding to the horizontal planning period as shown in FIG. 2B is extracted. Note that if the low-pass filter (107) system is not provided here, the starting end of the pulse signal to be extracted will be shown by a broken line.

That is, by providing the low-pass filter (107) system, the phase of the start end is advanced, and it is possible to counteract delays in the subsequent circuit.

Furthermore, in the above-mentioned circuit, when a parabolic wave like the curve e of the second C is supplied, the addition circuit (106)
provides a comparison level as shown by curve f. Here, the amplitude of the parabolic wave of the curve e has been increased by shortening the period, while the comparison level of the curve f has become a level corresponding to this change in amplitude. As a result, the comparison output in this case becomes a pulse signal as shown in the second diagram.

In the above circuit, by arbitrarily determining each constant, the period of the parabolic wave of curve a is set to T.

The pulse width of the output for this is T2, the period of the parabolic wave of the song ffMe is T3s, and the pulse width of the output for this is T4, T2 'r.

'r, T3 It can be done.

That is, according to the above-mentioned device, since the blanking signal is formed by comparing parabolic wave signals related to horizontal scanning at a predetermined level with respect to their amplitudes, the blanking signal is always compared with respect to the horizontal period regardless of changes in the horizontal frequency. A blanking signal can be formed at a constant ratio.

Furthermore, Figure @3 shows a specific connection diagram. In the figure, the same parts as in FIG. 1 are given the same reference numerals. Further, the value attached to each element l'c is an example of the element value, and the above-mentioned circuit can be constructed using this value.

〔Effect of the invention〕

According to the present invention, a parabolic wave signal (
101) at a predetermined level (105) with respect to its amplitude (104) to form a blanking signal (10g). Therefore, regardless of changes in the horizontal frequency, the blanking signal is always constant with respect to the horizontal period. It is now possible to form a blanking signal with a ratio of 5.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of the present invention, FIGS. 2 to 6 are diagrams for explaining the same, and FIG. 7 is a diagram for explaining a conventional device. (101) is an input terminal, (102) is a voltage division and DC removal circuit, (103) is a comparison circuit, (104) is a rectifier circuit,
(105) is a level control circuit, (106) is an addition circuit,
(lo7) is a low-pass filter, and (108) is an output terminal. Hidemori Matsukuma ゛Figure 1 Figure 2-1, 1- Figure 3

Claims (1)

[Claims] 1. A parabolic wave signal related to horizontal scanning is supplied to a comparator circuit at a predetermined level after removing a DC component, and a value obtained by rectifying the maximum amplitude of the parabolic wave signal is used to 1. A multi-scanning type receiver, characterized in that a comparison level of a comparison circuit is set, and the output signal of the comparison circuit is used to perform horizontal retrace blanking of a video signal. 2. Claim 1, characterized in that a signal obtained by integrating and delaying the parabolic wave signal is superimposed on the comparison level.
The multi-scanning receiver described in Section 1.