Mr. Bhardwaj,

Based upon your description, the highest
frequency used or generated by this digital
device is 1 Ghz.  In accordance with the chart in
Section 15.33(b)(1), this digital device must be
tested to 5 Ghz.  Scanning the frequency range
up to 10 times the operating frequency is
reserved for transmitters or intentional radiators
not unintentional radiators (digital devices).

Rich Fabina

>>> "Chaman Bhardwaj"
<Chaman_Bhardwaj@mw.3com.com> 02/24/98
04:16pm >>>
Mr.  Fabina;

I  am   asking  for  the interpretation  of  the
section  15.33  as
applies  to   unintentional  radiators;

The   digital  circuit  under  question  is   the  
external  clock
circuit  freq. which  operates  at   100MHZ,  in 
other  words   external
data  and  address   lines   speed  is  100MHz, 
however,  the   internal
data  and  address  lines  on  the   silicon  die 
of  the  microprocessor
are  running  at  1GHZ.  In  other  words, 
external  clock   signal  is
multiplied  inside  the    microprocessor  to 
supply 1GHZ  clock  for
internal  operation  of  the  microcontroller  (A 
and  D  bus).  Now  the
question  is  to  find  out  the  highest  frequency
  to  be  scanned  for
radiated  emissions  testing. Should it    be 
equal  to    10x100= 1GHZ
or   1GHZ  x 10  =  10 GHZ   ?

Regards,

Chaman





RFABINA@fcc.gov on 02/24/98 02:16:02 PM

To:   Chaman Bhardwaj/MW/US/3Com
cc:
Subject:  Re: More UK IEE Seminars -Reply