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RE: SJTP: Minutes from 08-May meeting




Well, I agree with both of your arguments.  But I still have a problem in that I don't know if the test procedure will work under modulation (as well as additional unnecessary testing).  My own tests were done without implementing FOTP 203 using a camera which is the intended methodology.  I will ask the 2.2.1 group for additional insight to see if they think it actually will work.  

So let me try a different line of argument.  Encircled flux is a component (i.e. transceiver), not a system test for which we already have a test procedure called out, namely FOTP 203.  We have a number of other component specifications which do not seem to require a test procedure description.  So then why does encircled flux need to have a description added?  I have tested 1 Gb transmitters without modulating them (which by the way I don't remember seeing any difference there either, with versus without modulation).  

Again, I apologize if I am missing something.  I am not trying to be argumentative, but rather trying to avoid potential problems in the future and possibly additional unnecessary costs from testing transceivers.  

mike

> ----------
> From: 	jmw[SMTP:jmw@bayarea.net]
> Sent: 	Tuesday, May 08, 2001 8:33 PM
> To: 	Bill Reysen
> Cc: 	Hackert, Michael J; serialpmd; 'Ben Brown'
> Subject: 	Re: SJTP: Minutes from 08-May meeting
> 
> i agree that tests which are done with anything that simulates a real end-use
> condition will return better indication than any DC condition (i don't have data
> either, it's just a combination of logical reasoning and personal experience).
> 
> but for this effort, isn't it also true that you must either describe a set of common 
> electrical characteristics for a transmitter or describe a common set of drive 
> conditions?  i expect the latter is a better choice, but don't know whether or not 
> the group is already working on that.
> --
> jmw
> 
> At 04:58 PM 08-05-01 -0600, Bill Reysen wrote:
> 
> 
> 
> 	[...]It also stands to reason that a modulated
> 	measurement would be a more accurate indicator of link perfromance but I don't
> 	know if data exists to support this.
> 
> 	"Hackert, Michael J" wrote:
> 
> 	> Ben,
> 	>
> 	> Hi.  Having only scanned minutes, I hate to sound ignorant.  However, I was
> 	> wondering if there was really a need to have the source modulated during the
> 	> encircled flux measurements as implied in your slide 3.
> 	>
> 	> TIA 2.2.1 never did any experimentation with modulation of the transceivers
> 	> during our development process.  I have done some tests myself which says
> 	> that the difference if any is hard to detect.  Not being a manufacturer of
> 	> transceivers and lacking that expertise, I will concede if the experts say
> 	> that it is necessary.  However, I am reluctant to add a requirement if it is
> 	> really only being included as a nice to have.
> 	>
> 	> mike
> 	>
> 
>