vhl in SAS3_EYEOPENING

Graeme Boyd why at pmcs.com
Tue Oct 22 13:58:00 PDT 2013


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1310222_f.htm">HTML-formatted message</a>

Thanks Harvey
So in looking at the spec more I have an issue:
	Table 45 allows C1, C2 & C3 to be controlled independently (for
	example only one of them can be "dec" while the other two are in
	a "hold" state)
	Yet the notes in tables 48/49 states: C2 = 1-|C1|-|C3| which
	does not allow the coefficients to be independently controlled
	(the peak-to-peak voltage is controlled by the K0 gain as shown
	in figure 137).
Which is correct?
If "|C1| + C2 + |C3| = 1" is correct, then Vhl should not change with
changing C1/C2/C3 (so for noise, a +/-20mVpp should be allowed). In
which case Vhl would be 2 times K0 as reported by the script (K0 in the
script is in mVpd rather than mVpp) and table 45 would need to be
updated. Further we may want to add an extra table to bound Vhl when K0
is changed (incremented/decremented).
If independent control of C1/C2/C3 is allowed, then figure 137 & Tables
48/49 need to be fixed up, and Vhl becomes much more complex to extract
|from the script (have to do multiple runs with different Tx amplitudes
and subtract twice the reported K0's).
Graeme
On Mon, 2013-10-21 at 17:11 +0000, Newman, Harvey wrote:
> Hi Graeme,
> 
>  
> 
> The definition of Vhl for SAS-3 is the largest peak to peak voltage
> over any 80 UI since this is the defined measurement interval. It is
> not intended to include noise on the measurement so averaging is
> allowed.
> 
>  
> 
> 
> Regards,
> Harvey Newman
> 
> LSI Corporation
> 
> (408) 433-4028
> 
> 
> 
>  
> 
> 
> From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Graeme
> Boyd
> Sent: Monday, October 21, 2013 8:15 AM
> To: Remby Taas
> Cc: why at pmcs.com; t10 at t10.org
> Subject: RE: vhl in SAS3_EYEOPENING
> 
> 
> 
>  
> 
> Remby
> 
> I would need someone (maybe Harvey or Alvin) to clarify the
> definiation of Vhl as used within SAS3.
> 
> Graeme
> On Fri, 2013-10-18 at 17:59 -0700, Remby Taas wrote: 
> 
> 
>  
> Graeme,
> Hi, would you have suggestion for the calculation of vhl(as defined by SAS3
spec) using any script output parameters?  or would the SAS3_EYEOPENING get
updated?
>  
> thnx,
> remby
>  
>  
> -----Original Message-----
> From: Graeme Boyd [mailto:Graeme.Boyd at pmcs.com] 
> Sent: Friday, October 18, 2013 5:32 PM
> To: Remby Taas; t10 at t10.org
> Subject: RE: vhl in SAS3_EYEOPENING
>  
> The definition of Vhl from sas3r05g is "the peak-to-peak voltage
measurement in the interval t1 to t1+80T", which I originally thought was the
same thing as "Maximal Peak Low-frequency Amplitude (K0)" as reported by the
script. However the values for Vhl(k+1)-Vhl(k) in table 45 vary between the 3
values (-20 to +20; -40 to -10; +40 to +10) - only the first makes any sense
based on Vhl being the same thing as K0.
>  
> Graeme
> ________________________________________
> From: owner-t10 at t10.org [owner-t10 at t10.org] on behalf of Remby Taas
[rembyt at marvell.com]
> Sent: October-17-13 3:04 PM
> To: t10 at t10.org
> Subject: vhl in SAS3_EYEOPENING
>  
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Remby Taas <rembyt at marvell.com>
> *
> I'm doing TX-char sim with 3x waveforms(incl. no-eq ref), and I get the
following results...
>  
> TX_FFE_diff =
>     0.1875   -0.2940	 -0.1066
>   -31.7138  -33.1855	  2.0598
>  
> K0 =
>     0.3702
>     0.3703
>     0.3699
>  
> V1V2V3_diff =
>     0.0997	0.0208	 -0.1181
>   -25.1636  -23.6397	 -0.1779
>  
>  
> How/Where do I calculate/get the equivalent VHL?
>  
>  
> The given/resulting V1V2V3 are the SAS3's v1, v2, v3 deltas, but the vhl is
not given for each case.
>  
>  
>  
> *
> * For T10 Reflector information, send a message with
> * 'info t10' (no quotes) in the message body to majordomo at t10.org



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