[SAC-HELP] Transfer problem

Robert Casey rob at iris.washington.edu
Fri Feb 21 07:33:55 PST 2014 

	Thanks for the helpful reply, Philip.  I had Mary Templeton looking at it and she came the same conclusion as you.  She made a plot to illustrate:





	So the recommendation, I take it, is for the frequency of sensitivity, Blockette 58, stage 0, field 5 to be changed to 1.00000E+00.

	What I noticed was that the Normalization frequency of stage 1 is in fact set to 1 Hz, so I wonder if this is a product of merging the sensor to a datalogger response and then not seeing a trickle-down alteration of the frequency of sensitivity to stage 0?  The PDCC tool doesn't handle this, for example, but I do recall having discussions about this and seeing the solution as ambiguous.

	So if Blaine edits the RESP file, is that the way to proceed?

	-Rob


> 
> Hi
> 
> Responses are at best confusing, but you need to remember that the gain is not just a value, it is a value at a particular frequency. 
> 
> The last stage (stage zero) is supposed to be the overall gain and should be the product of the gains at each stage, but only if the frequency of each stage is the same. In this case the stage zero gain is +1.25829E+09, but it is given at freq of 5e-2. The stage 1 gain is 1.5e3, but at a freq of 1Hz. So to be proper, you must adjust the gain based on the poles and zeros from 1Hz to 5e-2 Hz before you multiply. Looking at the response plot here:
> 
> http://service.iris.edu/irisws/evalresp/1/query?net=ET&sta=CPCT&loc=00&cha=HHZ&time=2009-06-07T00:00:00&units=def&annotate=true&output=plot
> 
> it looks like 5e-2 is just barely beyond the flat part of the response, which explains why evalresp says that the stage 1 gain is  1.369329E+03 instead of 1.5e3. It has rolled off just a bit at 5e-2 Hz compared to 1Hz which is in the flat part of the response.
> 
> To be honest, I think that the mistake in this response is not in the gain numbers, but rather in the frequency reported in the stage zero. It probably should have the frequency in the stage zero as 1Hz instead of 5e-3Hz . So, likely in this case the 1.25829E+09 is the gain you want to use even though evalresp complains.
> 
> Hope this helps,
> Philip
> 
> 
> 
> On Thu, Feb 20, 2014 at 1:44 PM, Brian Savage <savage at uri.edu> wrote:
> Dear Blaine,
> 
> This error is generated by evalresp.  You should be able to confirm this by running evalresp on your RESP file.
> 
> For example
> % evalresp CPCT HHE 2010 001 0.001 20 -v -f RESP.ET.CPCT.HHE.2
> << EVALRESP RESPONSE OUTPUT V3.3.3 >>
>  WARNING (norm_resp): computed and reported sensitivities differ by more than 5 percent. 
> 	 Execution continuing.
>  --------------------------------------------------
>   RESP.ET.CPCT.HHE.2
>  --------------------------------------------------
>   ET CPCT 00 HHE  2009,001,00:00:00 2011,026,00:00:00
>    Seed units: Velocity(in)->Counts(out)
>    computed sens=1.14868E+09 (reported=1.25829E+09) @ 5.00000E-02 Hz
>    calc_del=8.92261E-01  corr_app=8.92261E-01  est_delay=8.92261E-01  final_sint=0.01(sec/sample)
>       stage  1: LAPLACE     A0=6.259322E+08 NZeros=  2 NPoles=  5 Sd=1.369329E+03
>       stage  2: GAIN        Sd=1.000000E+00
>       stage  3: FIR_SYM_1   H0=1.000000E+00 Ncoeff=  1 SamInt=1.953125E-06 Sd=8.388610E+05
>       stage  4: FIR_SYM_2   H0=1.000000E+00 Ncoeff= 36 SamInt=1.953125E-06 Sd=1.000000E+00
>       stage  5: FIR_SYM_2   H0=1.000000E+00 Ncoeff=  6 SamInt=1.562500E-05 Sd=1.000000E+00
>       stage  6: FIR_SYM_1   H0=1.000000E+00 Ncoeff=  7 SamInt=3.125000E-05 Sd=1.000000E+00
>       stage  7: FIR_SYM_2   H0=1.000000E+00 Ncoeff= 48 SamInt=6.250000E-05 Sd=1.000000E+00
>       stage  8: FIR_SYM_2   H0=1.000000E+00 Ncoeff=126 SamInt=2.500000E-04 Sd=1.000000E+00
>       stage  9: FIR_SYM_1   H0=1.000000E+00 Ncoeff=501 SamInt=5.000000E-04 Sd=1.000000E+00
>       stage 10: FIR_SYM_1   H0=1.000000E+00 Ncoeff=501 SamInt=1.000000E-03 Sd=1.000000E+00
>       stage 11: FIR_SYM_1   H0=1.000000E+00 Ncoeff=501 SamInt=2.000000E-03 Sd=1.000000E+00
> --------------------------------------------------
> %
> 
> Possibly someone at IRIS can comment on this further.  I think the first gain value is being modified due to a Analog PoleZero.
> 
> Brian
> savage at uri.edu
> 
> On Feb 18, 2014, at 4:57 PM, Blaine Bockholt (bbckholt) wrote:
> 
>> I am attempting to remove the instrument response of some data.  I downloaded the RESPFILE from IRIS and while using the evalresp option of transfer, I get the following error:
>> 
>> "WARNING (norm_resp): computed and reported sensitivities[ET.CPCT.00.HHE] differ by more than 5 percent."
>> 
>> I thought the final sensitivity at the end of the file is the product of all the different gain/sensitivities of each stage.  When I calculate it by hand, I get the sensitivity reported.  I am not sure where this error is coming from, nor I am sure how SAC calculates the sensitivity.  Thanks.
>> 
>> Blaine
>> 
>> Here is the command I use
>> 
>> trans from evalresp fname ET.CPCT.resp to none freqlim 0.001 0.002 15 20
>> _______________________________________________
>> sac-help mailing list
>> sac-help at iris.washington.edu
>> http://www.iris.washington.edu/mailman/listinfo/sac-help
> 
> 
> _______________________________________________
> sac-help mailing list
> sac-help at iris.washington.edu
> http://www.iris.washington.edu/mailman/listinfo/sac-help
> 
> 
> _______________________________________________
> sac-help mailing list
> sac-help at iris.washington.edu
> http://www.iris.washington.edu/mailman/listinfo/sac-help

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.iris.washington.edu/pipermail/sac-help/attachments/20140221/864297cc/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ET.CPCTresp.png
Type: image/png
Size: 125428 bytes
Desc: not available
URL: <http://www.iris.washington.edu/pipermail/sac-help/attachments/20140221/864297cc/attachment.png>

More information about the sac-help mailing list