Ask for Pentax DSLR internal craft improvement (II)

Started Nov 25, 2008 | Discussions thread
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PeterZheng Regular Member • Posts: 315
Ask for Pentax DSLR internal craft improvement (II)

EMI/EMC craft technics way and image's noise / by PeterZheng

In the summer of 2008, a Japanese media had interviewed the Pentax imaging department, including this kind of dialogs:

田中 氏「 基板からもノイズが出るんですか」

山本 氏「 そうですね。初めてのセンサーだったので、合わせながら徐々に改善して…」

田中 氏「 フレキシブルの基板からもノイズが出てくる可能性があるんですか?」

山本 氏「 画像に対するノイズという意味ではそうです。センサーの周辺なんかは影響することがあります。…」
(Japanese media) Mr. Tanaka:" the PCB also causes the image noise? "

(Pentax) Mr. Yamamoto:" It is. And it was the new sensor, while matching it and improves gradually…. "

Mr. Tanaka: "Is there a possibility that the noise occurs also from the flexible PCB (flat cable)?"

Pentax's Mr. Yamamoto:" In the image's sense to the noise is so. The image sensor's peripherals could affect the image's noise. "

Perhaps K20D had progresses, I am more anticipating Pentax K30D. I very agree with Yamamoto said words, but about EMI I still had more questions.

The influence to DSLR image's noise could be subject to several aspects:

1) The analog device's performance (image sensor CCD or CMOS, and ADE), the A/D circuit includes the analog portion.

2) Hardware's electronic craft and EMI/EMC performance, it has included the PCB wiring design, the electronic part's spatial arrangement, the image sensor cable's crafts way, the Anti-EMI craft method, etc.

3) Circuit design as well as auxiliary circuit's low-noise processing, the EMI reduces.
4) Software / firmware technology level.
5) Digital circuit and its hardware performance.

They all are important, but here will discuss 2nd point.

In the signal quantification and digital coding become the digital signal ago, that image signal is still the analog signal. In the signal to A/D converted ago, the signal amplifier is also an analog circuit, and they are some small-signal analog circuits, which vulnerable to the EMI/EMC effecting.

The camera's EMI / EMC craft it is by no means alone in order to obey with FCC or EU standards, the camera' s EMC performance achieves FCC or EU criterion is not difficult. Between the camera's EMI/EMC craft technology and its image's noise both are relevant more.

The small-signal analog circuit's low-noise design and processing are an important technology, in the digital Age, which digital circuit and small-signal analog circuit frequently mixed, and then the processing EMI/EMC is an important content.

Along with semiconductor craft tiny more, the low power loss, then the voltage is also more and more low, it is not conducive to the analog circuit and A/D circuit's SN ratio, which EMI/EMC craft will become more important.

The image's noise is along with the higher sensitivity ISO becomes more obvious. The EMI/EMC's influence is along with the higher sensitivity ISO becomes more obvious.

A front small-signal analog circuit better state would be more conducive to the image quality and noise control. When the image or audio signal has passed through the front's poor small-signal analog circuit, then attempt to use the latter's digital circuit obtains the high-quality image or the audio effect, it is impossible, with today's applied technology condition.

If the digital noise reduction to be overmuch has abused, then the image quality would be harmed.

The digital noise reduction technology no doubt is important, but this is one supplementary means, that it cannot rely on excessively.
(below continues, the pictures and text)

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(I am sorry for my poor English to could hinder your reading)
my article is also here:
Ask for Pentax DSLR internal craft improvement (II)
Ask for Pentax DSLR internal craft improvement (I)

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