Embedded Systems Conference
Breaking News
Comments
Newest First | Oldest First | Threaded View
Guru of Grounding
User Rank
Author
re: Electrical noise and mitigation - Part 2: Ground loops, noise transmission and shielding
Guru of Grounding   9/3/2010 7:13:18 PM
NO RATINGS
What I was told by Belden (and it makes perfect sense) is that different color wires must have insulation applied by different extruders (where liquid PVC coats bare wire pulled through a small die). The tolerances on the die, and therefore, insulation thickness can vary by .001". Using 8451 as an example, this makes capacitance change by about 5%. However, by grounding a (balanced interface) cable shield only at the source end, most of the CMRR-degrading effects of the capacitance imbalance disappear. My generic seminar (see http://www.jensen-transformers.com/an/generic%20seminar.pdf) explains in detail.

Guru of Grounding
User Rank
Author
re: Electrical noise and mitigation - Part 2: Ground loops, noise transmission and shielding
Guru of Grounding   9/3/2010 5:21:56 AM
NO RATINGS
I fail to see how the circuit in Figure 8.19 is "balanced". When one of the signal lines is grounded, the interface is unbalanced by definition. Also, anyone who believes that two conductors in a shielded cable have equal capacitance to the shield is a fool! If the wires are different colors (no joke), their capacitances can easily differ by 5% or more. I've measured this myself on many commercial cables (try Belden 8451, for example). Bill Whitlock, president & chief engineer of Jensen Transformers www.jensen-transformers.com and Fellow of the Audio Engineering Society

chcuk
User Rank
Author
re: Electrical noise and mitigation - Part 2: Ground loops, noise transmission and shielding
chcuk   12/24/2008 2:50:11 AM
NO RATINGS
It is very good and comprehensive. But it seems to me that we need have a different approach for electrostatic or magnetic problem. Sometimes they are even against each other. The point is what is the scenario of which, electrostatic or magnetic play more dominant role.



Top Comments of the Week
Flash Poll
Radio
LATEST ARCHIVED BROADCAST
EE Times Senior Technical Editor Martin Rowe will interview EMC engineer Kenneth Wyatt.
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Special Video Section
After a four-year absence, Infineon returns to Mobile World ...
A laptop’s 65-watt adapter can be made 6 times smaller and ...
An industry network should have device and data security at ...
The LTC2975 is a four-channel PMBus Power System Manager ...
In this video, a new high speed CMOS output comparator ...
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
10:29
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...
TE Connectivity's clear-plastic, full-size model car shows ...
Why culture makes Linear Tech a winner.
Recently formed Architects of Modern Power consortium ...
Specially modified Corvette C7 Stingray responds to ex Indy ...
Avago’s ACPL-K30T is the first solid-state driver qualified ...
NXP launches its line of multi-gate, multifunction, ...