Topband: Filters and grounding

[Jim Brown]

For those of you unable (or unwilling) to chase down Whitlock's 
JAES papers, here's a link to the pdf of a tutorial that I 
presented to an IEEE EMC conference three years ago. It includes a 
presentation of Whitlock's work on balanced interfaces. That 
material isn't in the other pieces on my website because Whitlock 
and I did several tutorial workshops together, and he presented 
his own work. He wasn't able to fit the IEEE conference into his 
schedule, so I did it for him.  My presentation used four ppt 
files. The one below is the one with Whitlock's balanced interface 
work. 

http://audiosystemsgroup.com/IEEE-Tutorial05.pdf

BTW -- one thing I failed to include in an earlier post is a 
definition of "hybrid" bonding for balanced shielded cables, the 
long standing good practice of a DC bond of the shield of a 
balanced cable at one end, and a bond through a capacitor at the 
other end. The Neutrik EMC XLR connector described in several of 
my presentations started out life as my invention, developed and 
turned into a product by Neutrik. It's essentially a 
"feedthrough" for the shield, with a very low impedance to at 
least 1 GHz. (I haven't seen data for how high it remains low, but  
it is known to be effective in suppressing problems with 1.8 GHz 
cell phones). It can be wired so that the shield has only a 
capacitive termination to the shell (chassis), or with a 
termination to pin 1 at DC and to the chassis above about 30 MHz. 
The connector is available in both male and female versions. 

73,

Jim Brown K9YC