KR100189052B1 - Palm form color ccd camera - Google Patents

Abstract

The present invention relates to a PAL-M type color CCD camera, comprising: first clock generating means for generating a main clock frequency through a crystal oscillator and a frequency divided by 1/2 of an output frequency of the first clock generating means; A timing generator for generating the second clock generator; a second clock generator for generating a PAL-M type color synchronization clock frequency; and output frequencies of the second clock generator and the timing generator; Phase comparison means for comparing the phases and outputting a phase difference between the two signals, phase synchronization means for varying the main clock frequency output from the first clock generating means by the phase difference, and color synchronizer outputted from the phase comparison means It consists of an encoder that receives signals and burst signals and outputs composite video signals. The PAL-M is configured to fit the specifications of the scheme relates to a color CCD camera, PAL-M, which can be easily used without any special measures in PAL-M broadcast area the way.

Description

Arm-M Color CD Camera

1 is a block diagram of a conventional NTSC-M color CD (CCD) camera,

2 is a block diagram of a PAL-M type color CCD camera according to an embodiment of the present invention.

The present invention relates to a PAL-M type color CCD camera, and more specifically, to a PAL-M type color CCD camera applicable to a PAL-M (Phase Alternation by Line-M) broadcasting standard (Brazil broadcasting standard). It is about.

Hereinafter, a conventional NTSC-M type color CCD camera will be described with reference to the accompanying drawings.

1 is a block diagram of a conventional NTSC-M type color CCD camera.

As shown in FIG. 1, in the conventional NTSC-M (National Television System Committee-M) system, 1/2 of the main clock frequency (frequency of the crystal oscillator) output from the main clock generator 10 is 28.6363 [MHz]. A frequency of 14.318 [MHz] is input to the synchronization generator 30 and used as a color synchronization signal.

Therefore, if one crystal oscillator is used when configuring the camera's internal system, it becomes possible to configure a CCD camera applicable to the NTSC-M method.

However, in the PAL-M system, the frequency of 14.318 [MHz], which is 1/2 of the frequency 28.6363 [MHz] output from the main clock generator 10, is equal to 14.302 [MHz], which is the color synchronization frequency of the PAL-M system. Since there is no coincidence, the phases of the two frequencies must be matched every horizontal period.

Therefore, in order to use a color CCD camera in a PAL-M broadcasting area, it is inconvenient to configure a system using a phase locked loop circuit for synchronizing the phases of the two frequencies every horizontal period. .

Accordingly, an object of the present invention is to solve the conventional inconvenience as described above, and according to the PAL-M broadcasting standard because the phase of the main clock frequency input through a simple circuit matches the phase of the color synchronization frequency of the PAL-M system. The present invention is to provide a PAL-M type color CCD camera designed to be applied.

A configuration of this invention for achieving the above object comprises: first clock generating means for generating a main clock frequency through a crystal oscillator; Generates a frequency divided by 1/2 of the output frequency of the first clock generating means, and generates a timing for outputting a control signal for controlling the shutter speed according to the input synchronization signal by receiving the vertical and horizontal synchronization signals. Means; Second clock generation means for generating a PAL-M type color synchronization clock frequency; Phase comparing means for receiving the output frequencies of the second clock generating means and the timing generating means, comparing the phases of the two input frequency signals and outputting a phase difference between the two signals; A phase synchronizing means for varying the main clock frequency output from the first clock generating means by the phase difference by integrating the phase difference signal outputted from the phase comparing means and converting it into an analog amount and outputting it to the first clock generating means and; And an encoder for receiving a color synchronizing signal and a burst signal output from the phase comparing means and outputting a composite video signal.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention in detail.

2 is a block diagram of a PAL-M type color CCD camera according to an embodiment of the present invention.

As shown in FIG. 2, the configuration of the color CCD camera of the PAL-M system according to the embodiment of the present invention,

A main clock generator 10 for generating a frequency of the main clock 28.6363 [MHz] through the crystal oscillator;

A frequency CL of 14.318 [MHz] is generated by dividing the output frequency f1 of the main clock generator 10 by 1/2, and the vertical and horizontal synchronization signals VD and HD are input to the input synchronization signal. Therefore, the timing generator 20 for outputting a control signal for controlling the shutter speed;

A voltage controlled oscillator 50 (hereinafter referred to as VCO) for generating a frequency f2 of 14.302 [MHz], which is a PAL-M color synchronization clock frequency;

A synchronization generator (30) for receiving the output frequencies (f2, CL) of the VCO (50) and the timing generator (20), comparing the phases of the two input frequency signals, and outputting a phase difference between the two signals;

By integrating the phase difference signal output from the synchronization generator 30 and converting it into an analog amount and outputting it to the main clock generator 10,

A low pass filter (LPF) (hereinafter referred to as LPF) for varying the main clock frequency f1 outputted from the main clock generator 10 by the phase difference;

The encoder 40 is configured to receive a color sync signal and a burst signal output from the sync generator 30 and to output a composite video signal.

Operation of the PAL-M type color CCD camera according to the embodiment of the present invention made as described above is as follows.

In general, in processing an image signal, a complete image signal may be obtained only when the phases of the main clock frequency and the color synchronization frequency coincide with each other. Accordingly, the PAL-M type color CCD camera according to the embodiment of the present invention is configured to synchronize the phase of the crystal oscillator's clock frequency (28.6363 [MHz]) with the phase of the color synchronizer frequency (14.302 [MHz]). It is.

As described above, in order to synchronize the phases of two clock frequencies, the phases of two clock frequencies must be compared first. The comparison method is as follows.

As shown in FIG. 2, first, the main clock frequency (f1 = 28.6363 [MHz]) oscillated from the main clock generator 10 is input to the timing generator 20, and the timing generator 20 The frequency divided by 1/2 of the main clock frequency f1 (CL = 14.318 [MHz]) is output.

Next, the frequency CL is inputted to the synchronization generator 30, and the color synchronizing frequency f2 = 14.302 [MHz] generated through the VCO 50 is also simultaneously inputted to the synchronization generator 30. The phase difference function of the two clock frequencies is output to the output terminal Hcomout by the phase comparison function of the synchronization generator 30.

The output phase difference signal is input to the LPF 60, and the LPF 60 performs a function of integrating the input signal into an analog amount, thereby making the main clock 28.6363 [MHz] linear ( Linear) enables stable oscillation.

Here, the phase difference signal output from the synchronization generator 30 is a horizontal frequency divided by the output frequency CL = 14.318 [MHz] of the timing generator 20 and an output frequency f2 = 14.302 of the VCO 50. [MHz]) is a pulse type signal (DC voltage type) having a width equal to the phase difference between the divided horizontal frequencies.

In addition, the LPF 60 integrates the signal so as to become an analog value and outputs the result to the main clock generator 10 again, whereby the main clock frequency oscillated through the main clock generator 10 is changed by the phase difference, so that the main Ensure that the phase of the clock frequency coincides with the phase of the color sync frequency every horizontal period.

That is, the color CCD camera of the PAL-M system according to the embodiment of the present invention allows the synchronization of two clock frequencies by synchronizing only the main clock frequency without changing the color synchronization frequency.

Therefore, the effect of the color CCD camera of the PAL-M system according to the embodiment of the present invention operating as described above is configured to meet the standard of the PAL-M system, which is a Brazilian broadcasting system, so that there is no special means even in the PAL-M broadcasting region. It is easy to use.

Claims (3)

First clock generating means for generating a main clock frequency through the crystal oscillator; Generates a frequency divided by 1/2 of the output frequency of the first clock generating means, and generates a timing for outputting a control signal for controlling the shutter speed according to the input synchronization signal by receiving the vertical and horizontal synchronization signals. Means; Second clock generation means for generating a PAL-M type color synchronization clock frequency; Phase comparing means for receiving the output frequencies of the second clock generating means and the timing generating means, comparing the phases of the two input frequency signals and outputting a phase difference between the two signals; A phase synchronizing means for varying the main clock frequency output from the first clock generating means by the phase difference by integrating the phase difference signal outputted from the phase comparing means and converting it into an analog amount and outputting it to the first clock generating means and; And an encoder for receiving a color synchronizing signal and a burst signal outputted from the phase comparing means and outputting a composite image signal. The PAL-M type color CCD camera according to claim 1, wherein said phase synchronization means comprises a low pass filter. The PAL-M type color CCD camera according to claim 1, wherein the main clock frequency is 28.6363 [MHz].