JP2001245183A - Multi-scan electronic view finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-scan electronic view finder capable of supporting plural high-vision signals. SOLUTION: In the multi-scan electronic view finder for inputting a video signal by choosing from among plural high-vision video signals, a blanking pulse rocking the frequency of the inputted signal is created, by using two mono-multi vibrators according to the reference signal which is a horizontal synchronizing signal, obtained by synchronizing separation from the inputted video signal, and then the video signal is controlled by the blanking pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-scan electronic viewfinder.

[0002]

2. Description of the Related Art A conventional high-definition electronic view finder (hereinafter referred to as EVF) is 33.75 KHz / Hz.
Only one type of input signal of 60 Hz (33.72 KHz / 59.94 Hz) can be operated (displayed).

[0003] In the standard electronic viewfinder, NTSC (15.734 KHz / 60H) is also used.
z), there is no electronic viewfinder that can support both PAL (15.625 KHz / 50 Hz), and NTSC or PAL is set for each destination. The circuit is designed to be compatible with NTSC and PAL, and is fixed to one of them by jumper land or resistor short or open when adjusting.
The configuration was not adapted to both C and PAL.

FIG. 1 is a circuit block diagram mainly showing a deflection circuit of a high-definition electronic viewfinder according to the prior art. The horizontal synchronizing signal HD is synchronously separated from the VIDEO signal input to the HDTV electronic viewfinder by the synchronizing separation circuit 1, the horizontal synchronizing signal 11 is taken out from the synchronizing separation circuit 1, and input to the blanking pulse generator 9. A blanking pulse 12 created by setting a blanking period with a capacitor and a resistor externally connected to the monomultivibrator 10 is output and input to the signal processing circuit 15.

[0005] The VIDEO signal 13 is input to the deflection circuit 2. The deflection circuit 2 has a horizontal free-run frequency setting circuit 3, a vertical free-run frequency setting circuit 4, a horizontal image position setting circuit 5, a vertical blanking width setting circuit 6, a vertical screen size setting circuit 7, and a luminance setting circuit 8. , Each circuit is VI
The horizontal / vertical free-run frequency, horizontal image position, vertical blanking width, vertical scan size, and luminance are adjusted in accordance with the DEO signal 13. The VIDEO signal 14 output from the deflection circuit 2 is input to the signal processing circuit 15, subjected to blanking at the timing of the blanking pulse 12, and output. The signal 16 output from the signal processing circuit 15 becomes the G1 signal of the CRT 17.

FIG. 2 is a timing chart of a VIDEO signal, HD (horizontal synchronization signal), and BLK (blanking pulse) of a circuit according to the prior art. VIDEOA is a Hi-Vision signal having a frequency of 33.75 KHz / 60 Hz. The HDA generated by the horizontal synchronizing separation circuit from the video signal on which the horizontal synchronizing signal is superimposed is input to the mono multivibrator, and the mono multivibrator outputs the HDA.
A blanking signal synchronized with the rising edge of the video signal is generated using the rising edge of A as a trigger. The blanking time is set by constants of a capacitor and a resistor externally connected to the mono multivibrator. The next blanking pulse rises at the next rising edge of HDA. In a single mono-multi vibrator, a time A (a time during which blanking is not performed) from the end of the video signal to the rise of the next blanking pal occurs. However, the time A is minute, and the next blanking period ends after the blanking period ends. This is about 2% of the total time A before entering the ranking period, which is a level without any problem.

[0007]

The frequency of a Hi-Vision signal conforming to SMPTE 274M is 33.75 KH.
z / 60 Hz, 28.125 KHz / 50 Hz, 27.
Although there are 00KHz / 48Hz, etc., the following problems occur in the circuit of the conventional high-vision-compatible electronic viewfinder when a high-vision signal having a different frequency is input. For example, an electronic viewfinder corresponding to a frequency of 33.75 KHz / 60 Hz has a frequency of 28.125 KH.
When a signal of z / 50 Hz or 27.00 KHz / 48 Hz is input, 1) Blanking pulse cannot be created. 2) Since the horizontal free-run frequency and the vertical free-run frequency are shifted, synchronization is not achieved. 3) The horizontal position of the image is shifted. 4) The vertical blanking width becomes short, and the vertical blanking period appears on the screen. 5) The vertical scan size increases. 6) Since the flyback pulse becomes large, the heater bias voltage changes and the screen brightness becomes bright.

In FIG. 2, a circuit that generates a blanking pulse in accordance with VIDEOA is added to SMPTE2.
High-definition signal conforming to 74M and frequency 28.12
The lower half of the timing chart shows the input of VIDEOB of 5 KHz / 50 Hz. The HDB generated by the horizontal synchronizing separation circuit from the video signal on which the horizontal synchronizing signal is superimposed is input to the mono multivibrator, and the mono multivibrator generates a blanking signal synchronized with the rising of the video signal using the rising of the HDB as a trigger. . Since the blanking time is set by the constant of the capacitor and the resistor externally connected to the monomultivibrator, there is no change. The next blanking pulse is HDB
Get up at the next rise. With one mono-multi vibrator, a time B (a time during which blanking is not performed) from the end of the video signal to the rise of the next blanking pulse occurs, and from the end of the blanking period to the start of the next blanking period. 20% of total time B
The blanking time is too long to play the role of blanking. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a multi-scan electronic viewfinder that can handle a plurality of high-definition signals.

[0009]

SUMMARY OF THE INVENTION In a multi-scan electronic viewfinder for selectively selecting and inputting a plurality of high definition video signals, a horizontal synchronization signal obtained by synchronizing and separating an input video signal is used as a reference signal. , A blanking pulse that follows the input signal frequency is created using two mono-multi vibrators, and a multi-scan electronic viewfinder that controls a video signal with the blanking pulse is used.

There are a plurality of horizontal free-run frequency setting circuits, a vertical free-run frequency setting circuit, a horizontal image position setting circuit, a vertical blanking width setting circuit, a vertical screen size setting circuit, and a luminance setting circuit corresponding to a plurality of HDTV signals. And an input frequency selection circuit for selecting an input frequency according to a frequency mode switching signal from the camera body, a horizontal free-run frequency setting circuit, a vertical free-run frequency setting circuit, and a horizontal image position corresponding to the selected input frequency. A multi-scan electronic viewfinder for selecting a setting circuit, a vertical blanking width setting circuit, a vertical screen size setting circuit, and a luminance setting circuit.

[0011]

FIG. 3 is a block diagram of a circuit of a multi-scan electronic viewfinder according to an embodiment of the present invention, and FIG. 4 is a VIDEO of the circuit according to the present invention.
(A, B, C) signal, HD (A, B, C) (horizontal synchronization signal), M / M1 (A, B, C) (output of mono multivibrator 1), BLK (A, B, C) 5 is a timing chart of (a blanking pulse and M / M2 output), in which three types of A, B, and C are described. A is 3
3.75KHz / 60Hz, B is 28.125KHz /
50 Hz, C is a timing chart of 27.00 KHz / 48 Hz. Hereinafter, a circuit used in the present invention will be described with reference to FIGS. A horizontal synchronizing signal HD is synchronously separated from the VIDEO signal input to the electronic viewfinder by a synchronous separating circuit 20, and a horizontal synchronizing signal 21 is output from the synchronous separating circuit 20. The horizontal synchronizing signal 21 is input to a blanking pulse generation circuit 29, and is input to a mono multivibrator M / M1. M / M1 is triggered by the rising edge of HD and returns at a predetermined time (return timing is at the rising edge of the video signal), and is repeatedly triggered by the next rising edge of HD and returns at a predetermined time. M
/ M2 is triggered by the rising edge of M / M1, and outputs a blanking pulse that has been restored in a predetermined time. The return timing is the timing at which the video signal disappears. The period of the video signal is the same for A, B, and C. Also, HD
The same applies to the period from the rise of the video signal to the rise of the video signal.

The difference is in the periods A, B and C during which blanking is not applied in the prior art, but the blanking start is adjusted by M / M2 at the end of the video signal, and the blanking end timing is M / M1. Thus, the timing is adjusted to the timing at which the video signal starts, so that a blanking pulse that follows the input VIDEO signal can be created.

The deflection circuit 22 includes a horizontal free-run frequency setting circuit 23, a vertical free-run frequency setting circuit 24, a horizontal image position setting circuit 25, a vertical blanking width setting circuit 26, a vertical screen size setting circuit 27, and a luminance setting circuit. 28
Each circuit has three (A, B, C) horizontal free-run frequency setting circuits (23A, 23B, 23C) adjusted according to VIDEO signal frequencies A, B, and C, and a vertical free-run frequency setting. Circuits (24A, 24B, 24C),
Horizontal image position setting circuits (25A, 25B, 25C), vertical blanking width setting circuits (26A, 26B, 26)
C), a vertical scan size setting circuit (27A, 27B,
27C) and a luminance setting circuit (28A, 28B, 28C). A, B, and C of each circuit are set, and when a frequency mode switching signal is input to the frequency selection unit 30 from the video camera, A, B, and
One is selected from the set of C. Therefore, the circuit adjusted for the type of the input VIDEO signal can be selected, and the problems [2] to 6) described in [0007], which are problems of the related art, are solved. The VIDEO signal 32 is input to the signal processing circuit 34, subjected to blanking by a blanking pulse 31, and output. The signal 35 output from the signal processing circuit 34 becomes the G1 signal of the CRT 17.

FIG. 5 is an example of a horizontal free-run frequency setting circuit diagram. The free-run frequency setting circuit 23 includes free-run frequency setting circuits 23A, 23B, and 23C preset for frequencies A, B, and C. When B or C is selected from the video camera by the frequency mode switching signal, the transistor TB or the transistor T
By C, the free-run frequency setting circuit 23B or the free-run frequency setting circuit 23C is selected. If B or C is not selected by the frequency mode switching signal, the free-run frequency setting circuit 23A is used.

A vertical free-run frequency setting circuit (24A,
24B, 24C), horizontal image position setting circuit (25A, 2C)
5B, 25C), vertical blanking width setting circuit (26
A, 26B, 26C), a vertical scan size setting circuit (27A, 27B, 27C), a luminance setting circuit (28A,
28B, 28C) are similarly adjusted and selected.

[0016]

By using two monomultivibrators in the blanking pulse generation circuit, the start of blanking can be adjusted at the end of the video signal, and the end of blanking can be adjusted at the start of the video signal. A blanking pulse that follows the input VIDEO signal can be created.

A plurality of horizontal free-run frequency setting circuits, a vertical free-run frequency setting circuit, a horizontal image position setting circuit, a vertical blanking width setting circuit, a vertical screen size setting circuit, and a luminance setting circuit corresponding to a plurality of HDTV signals are provided. Further, an input frequency selection circuit for selecting an input frequency according to a frequency mode switching signal from the camera body is provided, and a horizontal free-run frequency setting circuit, a vertical free-run frequency setting circuit, and a horizontal image position setting circuit corresponding to the selected input frequency are provided. Since a vertical blanking width setting circuit, a vertical screen size setting circuit, and a luminance setting circuit are selected, a multi-scan electronic viewfinder that can handle a plurality of high-definition signals can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a portion mainly including a deflection circuit of an electronic viewfinder according to a conventional technique.

FIG. 2 shows a VIDEO signal, HD of a circuit according to the prior art;
(Horizontal synchronization signal), BLK (blanking pulse) timing chart

FIG. 3 is a block diagram of a multi-scan circuit of the electronic viewfinder according to one embodiment of the present invention;

FIG. 4 shows a VIDEO (A, B, C) of the circuit according to the invention.
Signal, HD (A, B, C) (horizontal synchronization signal), M / M1
(A, B, C) (output of mono multivibrator 1),
BLK (A, B, C) (Blanking pulse, M
/ M2 output timing chart

FIG. 5 is a circuit diagram for setting a horizontal free-run frequency.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronization separation circuit 2 Deflection circuit 3 Horizontal free-run frequency setting circuit 4 Vertical free-run frequency setting circuit 5 Horizontal image position setting circuit 6 Vertical blanking width setting circuit 7 Vertical screen size setting circuit 8 Brightness setting circuit 9 Blanking pulse generator Reference Signs List 10 mono multivibrator 11 horizontal synchronization signal 12 blanking pulse 13 VIDEO signal 14 VIDEO signal 15 signal processing circuit 16 signal 17 CRT 20 synchronization separation circuit 21 horizontal synchronization signal 22 deflection circuit 23 horizontal free-run frequency setting circuit 24 vertical free-run frequency setting Circuit 25 Horizontal image position setting circuit 26 Vertical blanking width setting circuit 27 Vertical screen size setting circuit 28 Brightness setting circuit 29 Blanking pulse creation circuit 30 Frequency selection unit 31 Blanking pulse 32 VIDEO signal 33 VIDEO signal 34 signal processing circuit 35 signal VIDEO video signal HD horizontal synchronization signal BLK blanking pulse

Claims (2)

[Claims] 1. A multi-scan electronic viewfinder for selectively selecting and inputting a plurality of high-definition video signals, a mono-multivibrator using a horizontal synchronization signal obtained by synchronizing and separating an input video signal as a reference signal. A multi-scan electronic viewfinder characterized in that a blanking pulse following an input signal frequency is created using two of the above and a video signal is controlled by the blanking pulse. 2. A plurality of horizontal free-run frequency setting circuits, a plurality of vertical free-run frequency setting circuits, a horizontal image position setting circuit, a vertical blanking width setting circuit, a vertical screen size setting circuit, and a luminance setting circuit corresponding to a plurality of HDTV signals. Having an input frequency selection circuit for selecting an input frequency by a frequency mode switching signal from the camera body,
A horizontal free-run frequency setting circuit, a vertical free-run frequency setting circuit, a horizontal image position setting circuit, a vertical blanking width setting circuit, a vertical screen size setting circuit, and a brightness setting circuit corresponding to the selected input frequency are selected. The multi-scan electronic viewfinder according to claim 1, wherein