vhl in SAS3_EYEOPENING

Graeme Boyd why at pmcs.com
Thu Oct 24 16:44:50 PDT 2013


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1310243_f.htm">HTML-formatted message</a>

Remby
The script requires a single Tx amplitude for all Tx data files,
effectively making K0 the same and thus also assumes |C3|+ C2 + |C1| =
1.
If one allows Tx amplitude to vary, then you would be required to make
several SAS3_EYEOPENING runs (one per Tx amplitude or K0 setting). This
means that you would have to manually calculate the v1/v2/v3 & Vhl
diff's and make sure they are within specs.
At this time I have no plans on upgrading the SAS3_EYEOPENING script to
allow for multiple Tx amplitudes (one per measurement file). Note that
one could write a wrapper script that would call SAS3_EYEOPENING
multiple times and process the results.
Graeme
On Wed, 2013-10-23 at 10:40 -0700, Remby Taas wrote:
> Graeme,
> 
> Hi, would the script be updated to include the vhl then? 
> 
> also a question... in the current script would the results of v1v2v3
> be correct/accurate for the cases of independent coefficient update?
> (there was no assumption on K0 restriction?)
> 
>  
> 
> 
> thnx,
> 
> remby
> 
>  
> 
> 
> 
>  
> 
> 
> From: Newman, Harvey [mailto:Harvey.Newman at lsi.com] 
> Sent: Tuesday, October 22, 2013 3:53 PM
> To: why at pmcs.com
> Cc: Remby Taas; t10 at t10.org
> Subject: RE: vhl in SAS3_EYEOPENING
> 
> 
> 
>  
> 
> Hi Graeme,
> 
>  
> 
> Table 45 controls how a transmitter is allowed to be controlled by a
> receiver.  Independent coefficient control including reducing the
> overall amplitude using C2 is allowed. In this case there is not the
> restriction C2 = 1-|C1|-|C3|.
> 
>  
> 
> Table48 and Table 49 are controlling the simulation environment.  In
> these cases we are being more restrictive. In Table 48 the amplitude
> is controlled by K0 = 0.425 giving the minimum amplitude of 850 mVdpp.
> This is only the case if we also impose the restriction C2 = 1-|C1|-|
> C3|.	In Table 49 the end to end simulation needs to adjust the
> equalization but not reduce the amplitude in much the same was as
> Table 48. Therefore both are correct but in different cases.
> 
>  
> 
> While receivers are allowed to reduce the amplitude by adjusting C2
> most of the transmitter equalization test conditions are with
> amplitude at maximum.
> 
>  
> 
> Please let me know if there are any additional open issues.
> 
>  
> 
> 
> Regards,
> Harvey Newman
> 
> LSI Corporation
> 
> (408) 433-4028
> 
> 
> 
>  
> 
> 
> From: Graeme Boyd [mailto:why at pmcs.com] 
> Sent: Tuesday, October 22, 2013 1:58 PM
> To: Newman, Harvey
> Cc: why at pmcs.com; Remby Taas; t10 at t10.org
> Subject: RE: vhl in SAS3_EYEOPENING
> 
> 
> 
>  
> 
> 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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