伝送符号 [C2] 2B1Q

　更新 2013年1月3日

符号に関する概要は、「伝送符号とは」をご覧ください。

❑ C2.　Multilevel code　多値符号　4値の形式

多値符号は3値以上の電圧とパルスの組み合わせで表現するものをここに分類しました。ここで解説するのは4値の形式です。

C2-1.　2B1Q

　　
2B1Qは、DSL (IDSL, SDSL, HDSL) に使われた符号化方式です。いずれもDSLが普及し始めた初期の頃のものです。

DSL
Digital Subscriber Line
ADSLはDSLの一種。
ADSL＝Asymmetric Digital Subscriber Line
参考記事
ADSLについて詳細は、モデムとはをどうぞ。

符号化は、2ビットのデータと4種類の信号電圧レベルを組み合わせます。この方式の伝送容量（速度）の平均値はNRZ-Lに比べ2倍で、一つの符号あたり２つのデータを伝送できます。（NRZ-Lについて詳細は、伝送符号　[A2] Polar NRZ　ポーラーNRZの記事をどうぞ。）

2B1Q (2 Binary 1 Quaternary)
・m　　＝2　00, 01, 10, 11　データは4つのうちのどれか一つ
・B　　binary
・n　　＝1　データを表現する符号の長さ
・L　　＝4　信号レベルは4値（Quaternary「4つの要素」）

「多値符号」は「mBnL」の形式で名前が付いているものがあります。一般化するとそれぞれ文字の意味は次のとおりです。

Multilevel code　多値符号
・m　　データのバイナリーパターンの長さ
・B　　バイナリー (binary)
・n　　符号の長さ
・L　　信号レベル（電圧振幅）の数
2B1Q
2B1Q code
2B1Q code

「伝送符号 [C2] 2B1Q」への4件のフィードバック

  1. I would like to show thanks to you just for bailing me out of such a dilemma. Because of looking through the the web and seeing suggestions that were not productive, I figured my entire life was over. Living without the presence of solutions to the problems you’ve solved through your blog post is a crucial case, as well as those which may have negatively affected my entire career if I had not noticed your website. Your primary expertise and kindness in controlling a lot of stuff was very useful. I’m not sure what I would have done if I had not discovered such a point like this. I am able to now relish my future. Thanks for your time very much for this professional and effective guide. I won’t be reluctant to recommend the website to anyone who desires support about this topic.

    1. > I would like to show thanks to you just for bailing me out of such a dilemma. Because of
      > looking through the the web and seeing suggestions that were not productive, I figured my > entire life was over. Living without the presence of solutions to the problems you’ve solved
      > through your blog post is a crucial case, as well as those which may have negatively
      > affected my entire career if I had not noticed your website. Your primary expertise and
      > kindness in controlling a lot of stuff was very useful. I’m not sure what I would have done
      > if I had not discovered such a point like this. I am able to now relish my future. Thanks for
      > your time very much for this professional and effective guide. I won’t be reluctant to
      > recommend the website to anyone who desires support about this topic.

      I thouhght I would have a something to show my part of life. The topics in my blog was one
      of my interests, then I started to write related to communications engineering. Because
      of many people need to communicate by devices today. I studied again much things to write those
      articles. Thank you for your message. I hope my blog help you!

  2. Heya! I just wanted to ask if you ever have any trouble with hackers? My last blog (wordpress) was hacked and I ended up losing months of hard work due to no back up. Do you have any solutions to protect against hackers?

    1. > Heya! I just wanted to ask if you ever have any trouble with hackers? My last blog
      > (wordpress) was hacked and I ended up losing months of hard work due to no back up. Do > you have any solutions to protect against hackers?

      No, I never have a trouble with hackers. I have no idea of effective solution to protect.
      I have backup of each articles and whole of the site.

コメントは停止中です。