[SAC-HELP] a question about transfer command in Sac

Arthur Snoke snoke at vt.edu
Sun Jul 12 13:15:32 PDT 2009

I have been working on the transfer function, so I looked at your example.

A few comments:

It is not clear which version of sac you are using, as your command is 
sac2000.  It probably does not matter.

The command sequence


could be replaced by


only.  Try both ways and compare the lh output.

The command FREQ (short for FREQLIMITS) should have 4 arguments.  I am not 
sure what it means if you put in only two.  I am guessing that you want 
the filter response flat between 1 and 10 Hz.

Here is a run with settings I think do what you want.  I did not do all 
the tests.  Recall that a second call to transfer with no FREQ will 
probably use the values from the first time.  Not sure that is what you 

SAC> r 2000-08-03-0620-19S.TBZ___001_SP_E_TBZ___SP_E_SAC
SAC> rtr
  Slope and standard deviation are: -0.00089445 0.14512
  Intercept and standard deviation are: 0.13525 22.458
  Data standard deviation is: 1300.1
  Data correlation coefficient is: 5.3244e-05
SAC> transfer from polezero subtype ss1rd3_2.pz to WA FREQ 0.1 1.0 10.0 
  Extracting polezero response for TBZ  SP , SP E    ...

Station (TBZ  SP ), Channel (SP E    )
         Waveform multiplied by 1.000000 after deconvolution.
SAC> p1
SAC> ppk
SAC> write wa.sac
SAC> quit

Let me know if you (aor anyone else) have questions about what I am doing 
or claiming, as I want the next writeup on transfer to be both complete 
and accurate.

Arthur Snoke

On Sun, 12 Jul 2009, reza rezaei wrote:

> Hi
> I have a problem with transfer command in Sac.
> I have removed an instrument response and applied Wood Anderson to a
> wave in two different ways but I  saw some problems.
> First, I removed SS1 response with: transfer from polezero subtype
> $resp freq 1 10, then I applied WA response with this command:
> transfer to WA
> Furthermore, I did both with this command:  transfer from polezero
> subtype $resp to WA freq 1 10
>> From the above you might got idea that the result should be similar,
> but the results from the first and the second method are not similar.
> I have attached a file. Please run and look at the script in it. You
> can change parameters and test it. I am very grateful if you help me.
> Thanks,
> Reza

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