From caniglia at eecs.ucdavis.edu  Tue Jun 23 16:27:57 1992
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Date: Tue, 23 Jun 92 16:27:55 -0700
From: caniglia at eecs.ucdavis.edu (Michael Caniglia)
Message-Id: <9206232327.AA25331 at madrone.eecs.ucdavis.edu>
To: ptolemy-hackers at ohm.Berkeley.EDU
Status: O
Subject: help_please
Status: O
Content-Length: 1659

Dear "Giants of Ptolemy",

I'm trying to measure the BER of a communications model with an exclusive-OR gate
made from gates located in the DE domain.  However, my model is constructed of  
SDF stars from the main and dsp palettes and thus an error like this
results:

 vem> Unknown star 'Invert' in current domain, trying to load it...
 Error: star 'Invert' belongs to an incompatible domain.
 Check the galaxy's domain using edit-domain
 run finished 
 vem>

1) So, my question is: How do you guys at Berkeley track the BER?


 Note: (in the hardware lab we used an exclusive-OR to compare the input
 sequence with the data that was passed through the system.  We knew
 there was an error when the two sequences differed because the truth
 table: 

       ex-OR                        BER= bits in error/total bits
       00 0                              
       01 1
       10 1
       11 0
            ...and the total amount of bits were tallied 
	    by a digital frequency counter.)

2) I have the EE123 & 225A reader from Copy Central
and it seems as though some pages are missing.  Is there a bigger more complete
bound version of documentation for Ptolemy? 



3) I have an NRZ (non-return-to-zero) signal source made from the IIDUniform and Sgn stars.
In theory the Tb is the distance of the shortest pulse in the NRZ stream.  Thus, the bit rate 
should be 1/Tb? Right?  When I try to run this, the dialog window pops up and asks the user to
specify how many iterations.  I put in 100 and do not know what I am doing! Does sample rate
equal iterations?
How are iterations related to the bit rate (i.e. bits/sec)?

Thanks for your time,

Michael