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Siglent SDG1000 (aka LeCroy WaveStation) firmware updates

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commongrounder:
Right there is the problem.  We, as end users, do not have access to the location where the log sweep function is stored.  It is set in firmware, and requires a change in an updated version.  I have sent an email outlining this to Siglent.  They are apparently on vacation until May 3 for "Labor Day".  I think it would be excellent to be able to create and store custom sweep curves to suit the end user's needs.

nixxon:

--- Quote from: commongrounder on April 29, 2013, 03:09:58 pm ---I went ahead and sorted out the math needed to create the proper sweep envelope for a decade "log" function.  I am attempting to contact Siglent through their web site, but I am not at all certain that the messages are getting through, as there is no auto-acknowledgement email, or anything I have seen, so far.  I surely am not the only end user who has issues with this. :-\  If anyone has a direct email address to customer service at Siglent they are willing to share, that would be great.
Here is the formula with an example of an audio sweep of 20hz to 20khz over 10 seconds.

f(t) = fstart * 10(t * c)

c = log10(ffinal / fstart) / S

 where

 f(t) = a function giving the frequency in hz at time t
 t = the current time in seconds since the start of the sweep
 S = how long the sweep lasts in seconds (e.g. 10 seconds)
 fstart = the frequency at t = 0 in hz (e.g. 20hz)
 ffinal = the frequency at t = S in hz (e.g. 20,000hz)
 c = the 'time constant', as defined above (e.g. 0.3 for the example numbers above)

--- End quote ---

I tried your function in Excel and all I got was a straight line that increases at a rate of 10*c:

      A   B   C
14  fstart   1   Hz
15  ffinal   1000   Hz
16  S   10   seconds
17  c   0,3   (=LOG(B15/B14)/B16)) ("LOG"="LOG10" option in excel)
      
      
RESULTS:      
X-axis   Y-axis   
t   f(t)   
0   0   <--- the function is: =$B$14*10*(A23*$B$17) for value 0 in box B23
0,1   0,3   
0,2   0,6   
0,3   0,9   
0,4   1,2   
0,5   1,5   
0,6   1,8   
0,7   2,1   
0,8   2,4   
0,9   2,7   
1   3   
1,1   3,3   
1,2   3,6   
1,3   3,9   
1,4   4,2   
1,5   4,5   
1,6   4,8   
1,7   5,1   
1,8   5,4   
1,9   5,7   
2   6   

Did I do something wrong here?

Galaxyrise:
nixxon, I believe commongrounder meant:
f(t) = fstart * 10^(t * c)

which would be
=$B$14*POWER(10,(A23*$B$17))

in your spreadsheet

Fennec:
Hi,

I am not the expert in Excel, so please can you attach the file here ? Thank you.

commongrounder:
Yes, that is correct.  (t*c) was originally superscripted to indicate exponentiation. I'm guessing the superscript got lost somewhere, so it appeared like 10(t*c), which is linear. It should be 10 ^ (t*c).

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