RE: Interesting the 1st comment

Posted by Ugly (A) on July 22, 2015 at 09:57:15

In Reply to: RE: Interesting the 1st comment posted by jkeny on July 22, 2015 at 07:27:22:

In general transformers are designed to reject common mode signals while passing differential mode signaling, though nothing is perfect. Based on the construction and limitations set forth by mother nature, there is no such thing as a perfect transformer. Most common mode noise will be blocked by even crappy pulse type transformers as far as I know.

A problem with Ethernet circuitry CAN be common mode noise, sure. Diff signaling in itself only increases signal to noise ratio compared with the diff noise. However, the impedance "balancing" typically used in this type of circuitry allows for some amount of common mode noise rejection. Together they work to limit the negative affects of noise of both types.

The nature of the sum of the noise (common mode noise component plus differential mode noise component = sum of noise problem) problem will depend on the noise source and the victim circuits ability to reject it. In my experience the types of power supplies and high speed digital circuitry used in typical PC's can cause significant common mode and/or differential mode problems if not treated with care. Especially with low cost power supplies the diff mode and common mode filtering often employed to reduce these emissions and there are eliminated for cost reasons.

Poorly implemented circuits will be more susceptible. Awesomely implemented circuits will be less susceptible but not to the point of zero susceptibility, that would be impossible.

Depending on the source of the noise there is no guarantee you wont have differential mode noise problems in Ethernet circuitry nor is there any guarantee you wont have common mode problems...it all depends.

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Follow Ups Full Thread

Topic - Ars Technica listens to Audiophile Ethernet Cables - Jaundiced Ear 16:06:15 07/16/15 (34)

Milking it - Bromo33333 13:14:17 07/27/15 (0)

Just curious... - Jaundiced Ear 17:43:12 07/17/15 (1)

RE: Just curious... - Dave_K 08:00:25 07/19/15 (0)

Prepares to listen! - fmak 07:37:24 07/17/15 (0)

Interesting the 1st comment - beppe61 22:22:14 07/16/15 (26)

RE: Interesting the 1st comment - jkeny 01:48:05 07/17/15 (10)

RE: Interesting the 1st comment - Ugly 07:19:52 07/22/15 (4)

RE: Interesting the 1st comment - jkeny 07:27:22 07/22/15 (3)

RE: Interesting the 1st comment - Ugly 09:57:15 07/22/15 (2)

RE: Interesting the 1st comment - jkeny 10:24:53 07/22/15 (1)

RE: Interesting the 1st comment - Ugly 14:19:14 07/22/15 (0)

" isolation from RF noise " - beppe61 01:53:18 07/17/15 (4)

RE: " isolation from RF noise " - jkeny 02:28:44 07/17/15 (3)

RE: " isolation from RF noise " - beppe61 04:17:22 07/17/15 (2)

RE: " isolation from RF noise " - jkeny 04:48:35 07/17/15 (1)

RE: " isolation from RF noise " - beppe61 05:24:13 07/17/15 (0)

I liked this bit from the third comment: - Jaundiced Ear 23:16:53 07/16/15 (14)

RE: I liked this bit from the third comment: - beppe61 01:48:42 07/17/15 (13)

You are missing my point - Jaundiced Ear 02:31:55 07/17/15 (12)

RE: You are missing my point - Ryelands 03:34:24 07/17/15 (10)

Again, You are missing my point - Jaundiced Ear 03:58:53 07/17/15 (9)

RE: Again, You are missing my point - Ryelands 05:26:47 07/17/15 (7)

Hey Ryelands: Thank You - Sordidman 09:11:00 07/17/15 (6)

RE: Hey Ryelands: Thank You - Ryelands 09:21:23 07/17/15 (5)

RE: Hey Ryelands: Thank You - Sordidman 09:47:37 07/17/15 (4)

RE: Hey Ryelands: Thank You - Ryelands 10:14:24 07/17/15 (3)

RE: Hey Ryelands: Thank You - Bob_C 14:32:49 07/17/15 (0)

Ha!! Yipes, - i need a break.... :-) thanks -t - Sordidman 10:22:15 07/17/15 (1)

RE: Ha!! Yipes, - i need a break.... :-) thanks -t - Bob_C 14:36:41 07/17/15 (0)

RE: Again, You are missing my point - Mercman 05:03:18 07/17/15 (0)

RE: You are missing my point - beppe61 03:31:41 07/17/15 (0)

James Randi Alert! - Ivan303 18:13:43 07/16/15 (2)

Amazing !.................................nt - Cut-Throat 05:13:26 07/17/15 (1)

LOL! [nt] - Chris from Lafayette 11:05:19 07/17/15 (0)

Follow Ups

RE: Interesting the 1st comment - Ugly 09:57:15 07/22/15 (2)

RE: Interesting the 1st comment - jkeny 10:24:53 07/22/15 (1)

RE: Interesting the 1st comment - Ugly 14:19:14 07/22/15 (0)

RE: Interesting the 1st comment

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