Embedded Systems Conference
Breaking News
Comments
Newest First | Oldest First | Threaded View
JanineLove
User Rank
Author
IEEE EMC2013
JanineLove   8/5/2013 3:25:35 PM
NO RATINGS
Ken's in Denver this week for EMC. Ken, be sure to let us know how it goes.

Kenneth Wyatt
User Rank
Author
Re: EMC Questions
Kenneth Wyatt   8/4/2013 10:46:32 AM
NO RATINGS
Hi Sanjib.A, you pose several questions and I'll answer the best I can. As I'm not completely familiar with GTEMs, except from what I've read, you may need to consult other experts in the field.

I believe there is a "best" lower limit with GTEMS, depending on their size. So assuming the product you're testing does not exceed the size recommendation and the frequencies in question are - say - above 150 MHz, I've read they can be accurate enough for pre-compliance testing. Please correct me if I'm wrong...

As for your second question, there are "sources" of RF energy, such as devices producing fast edges (oscillators, buffers, ASICs, A/D, D/A, etc.) and these sources can couple via conductive, radiative, inductive or capacitive means to "radiating structures", such as cables, enclosure seams, etc.

Typically, it is common-mode currents that radiate via these radiating structures. As long as the loop area between the differential mode source and return currents is small, then DM emissions is usually a second-order effect.

A horizontal emission might come from a horizontal cable or a vertical seam, and visa versa with vertical emissions. You can also have a combination of the two.

Kenneth Wyatt
User Rank
Author
Re: Detailed
Kenneth Wyatt   8/4/2013 10:37:00 AM
NO RATINGS
Thanks elctrnx_lyf. You might also check The EMC Blog at: http://www.edn.com/electronics-blogs/4376432/The-EMC-Blog for additional Q&A following my webinar.

Sanjib.A
User Rank
Author
EMC Questions
Sanjib.A   8/4/2013 2:45:16 AM
NO RATINGS
Hello,

I missed the webinar, but thanks for sharing the link and Q&A. I have the following questions for which I have not got satisfactory answers:

1. Is it okay to use a GTEM cell to do the pre-compliance testing? I saw a big difference in the results when we tried to fix a power supply issue in GTEM cell vs when we tried the same fix in an anechoic chamber. Would you suggest avoiding GTEM cell for pre-compliance testing?

2. How to interpret about the source of the noise (PCB or Cable; Common-mode or diff mode) if a frequency component is appears in Horizontal scan but not in the vertical scan or vice-versa or appears in both?

Best Regards, 

elctrnx_lyf
User Rank
Author
Detailed
elctrnx_lyf   7/31/2013 1:19:56 PM
NO RATINGS
These extensive details are definitely helpful to understand the basic of Emc precompliance testing.



Radio
LATEST ARCHIVED BROADCAST
As data rates begin to move beyond 25 Gbps channels, new problems arise. Getting to 50 Gbps channels might not be possible with the traditional NRZ (2-level) signaling. PAM4 lets data rates double with only a small increase in channel bandwidth by sending two bits per symbol. But, it brings new measurement and analysis problems. Signal integrity sage Ransom Stephens will explain how PAM4 differs from NRZ and what to expect in design, measurement, and signal analysis.

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Most Recent Comments
David Ashton
 
rick merritt
 
rick merritt
 
Wilco1
 
KarlS01
 
KarlS01
 
TonyTib
 
perl_geek
 
The MicroMan
Like Us on Facebook
Special Video Section
The LTC®6363 is a low power, low noise, fully differential ...
Vincent Ching, applications engineer at Avago Technologies, ...
The LT®6375 is a unity-gain difference amplifier which ...
The LTC®4015 is a complete synchronous buck controller/ ...
10:35
The LTC®2983 measures a wide variety of temperature sensors ...
The LTC®3886 is a dual PolyPhase DC/DC synchronous ...
The LTC®2348-18 is an 18-bit, low noise 8-channel ...
The LT®3042 is a high performance low dropout linear ...
Chwan-Jye Foo (C.J Foo), product marketing manager for ...
The LT®3752/LT3752-1 are current mode PWM controllers ...
LED lighting is an important feature in today’s and future ...
Active balancing of series connected battery stacks exists ...
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 ...