EMI from 30 to 100mhz

Hi! I have a fast ethernet design that does not pass EMI from 30 to 100mhz and based on the scan it is common mode noise. In my design i have the phy connected to xfmr1--choke1---connector---I/O card---xfmr2choke2---rj21---cables---patch panel---rj45. Now, if I use shielded cables from RJ21 to

Re: Meeting CISPR in Fast Ethernet board

ith unshielded cables, we have found that > on multi-layer PCBs that has > a good low impedence multi-point grounding system, > the use on a continuous 0 > volt plane across the whole PCB works the best. > > Hope this helps > > Kind regards, > Chris. > > > > &

Meeting CISPR in Fast Ethernet board

Hi! I had a question regarding meeting EMI on my board for CISPR. I have a Fast Ethernet card and the 125MHz Fast Ehternet fails the CISPR in the 30Mhz to 100Mhz limit. In the layout care has been taken to isolate the chassis or quiet ground from Digital ground by isolating the ground from the se

Use of resistor on the front end of E1design

Hi! I had a question regarding the use of a resistor between TIP/RING of E1 interface before the protection circuitry. 1)on the E1 interface there is protection circuitry but the designer wants to put befoer this circuitry i.e. on line side a 120ohm resistor between TIP/RING. The resistor mfgr. gu

T1/E1 compliance requirements

Hi! I had recently posted a question to SI on the testing requirements for T1/E1 i.e. EMC requirements and I wanted to get some more feedback from this list to make some decisions. For our current T1/T3 products we don't for any lightning tests since our product sits in the CO and presumably we wi