PSN-L Email List Message

Subject: Re: Old hobby resurgence
From: Bob McClure bobmcclure90@.........
Date: Mon, 17 Sep 2012 16:10:29 -0400


Hi Ed,

  Amaseis also has the inverse filter which can only be used on SAC files,
so you can still try out inverse filtering on event files.

Bob


On Mon, Sep 17, 2012 at 1:10 PM, Edward Ianni  wrote:

>  Hi Bob;
>       Good to hear from you. I am using Amaseis and was looking for a
> simple circuit to hang on the back of the Seismometer (like the Black Box
> apparently has within it, to extend the period(s). I tried "Roberts's",
> years ago, but did not want to "insert/inject" it into the existing
> circuit, thus the desire to "hang" some electronics directly behind the
> seismometer(s) to increase their periods. Thanks, Ed.
>
> On 9/17/2012 9:45 AM, Bob McClure wrote:
>
> Hi Ed,
>
>    Software is available for period extension. Please note the following
> letter from Larry.
>
>  Bob
>
>
>  from: Larry Cochrane lcochrane@..............
> to: psnlist@..............
> date: Tue, Feb 7, 2012 at 1:11 AM
> subject: Robert's circuit and new WinQuake / WinSDR releases
> http://www.seismicnet.com/psnlist/120206_221156_1.html
>
>  Hi Everyone,
>
>  Last year I incorporated Bob McClure's inverse filter into WinQuake and
> WinSDR. See http://sites.google.com/site/bobmcclure90/inversefilter for
> more information on Bob's filter. You can try the filter in WinQuake if you
> install this beta release:
>
>  32-Bit: http://www.seismicnet.com/software/wq323b_32bit.exe
> 64-Bit: http://www.seismicnet.com/software/wq323b_64bit.exe
>
>  And if you have a PSN ADC board you can use the filter in real-time by
> using the current WinSDR beta release available here:
> http://www.seismicnet.com/winsdr/winsdr4x.html.
>
>  Please Note! In WinQuake the pendulum frequency is entered in seconds so
> a 4.5 Hz geophone would be entered as 0.222. In WinSDR the frequency is
> entered in Hertz, so a 20 second Lehman would be entered as .05. I should
> normalize this, I'm just not sure if I should change WinQuake or WinSDR...
>
>  In WinQuake the inverse filter can be found in the Time-Domain Filter
> dialog box and in WinSDR the Channel Settings -> Integrate / Filter tab
> dialog box.
>
>  A few days ago there were some emails on the list regarding what numbers
> to use for the pendulum frequency and high-pass filter. The pendulum
> frequency is the undamped period of your sensor. If you have a geophone
> this would normally be 4.5 Hz (WinSDR, .222 in WinQuake) or maybe 1 if you
> gave a 1 Hz geophone or AS1 type of sensor. This number sets where the
> filter starts to boost the lower frequencies to compensate for the drop off
> of sensitivity below the period of the sensor. The high-pass filter sets
> how much you want to extend the period of the sensor. It should be set to
> some number below the period of the sensor. Depending on the sensor and
> electronics, mainly the first op-amp, you might be able to extend the
> period by one decade.
>
>  Before adding the software filter to WinSDR and WinQuake I played around
> with the Robert's circuit. My results regarding using this filter, both in
> hardware and software, can be found here: http://www.seismicnet.com/epf/
>
>  Below is some information on the event files on my system that use this
> filter in WinSDR:
>
>  *.LCSV1.psn - This is a volume set from a Kinemetrics SV-1 5-Second
> intermediate-period vertical sensor. The LCZS1 channel is the raw data from
> the sensor. The LCZS2 channel has been period expended to 25 seconds
> (.04Hz) and then a 2 pole 2 Hz low-pass filter is applied to the data. This
> helicoder plot (updated every 5 min)
> http://www.seismicnet.com/quakes/images/lczs2.png shows the 24 hour graph
> from this channel. Teleseismic events show up much better on the inverse
> filter channel then the raw data channel.
>
>  *.LC45v.psn - This is a volume set from a horizontal 4.5 Hz geophone.
> The LCEG1 channel is the raw data from the sensor and the LCEG2 channel has
> been period extended to 5 seconds or .2 Hz. This PSN event file
> http://www.seismicnet.com/quakes/1201/120126.021845.lc45v.psn is a good
> example of an earthquake recorded from this sensor.
>
>  I would like to thank Bob McClure for supplying the Visual Basic code so
> I could add this feature to my programs.
>
>  Regards,
> Larry Cochrane
> Webtronics
> ====
>
> On Mon, Sep 17, 2012 at 9:22 AM, Gerald Payton  wrote:
>
>>  You may find your info at:
>> http://www.jclahr.com/science/psn/roberts/index.html
>>
>> Regards,
>>
>> Jerry
>>
>>
>>
>> *From:* Edward Ianni [mailto:edwianni1@............
>> *Sent:* Monday, September 17, 2012 5:52 AM
>> *To:* psnlist@..............
>> *Subject:* Re: Old hobby resurgence
>>
>>
>>
>> Hi Chris;
>>       I see that you are still giving out great information and advice.
>> Could you possibly " point" me to the schematic of the serial AS-1 period
>> "extender". As I recall I built the Roberts circuit years ago with limited
>> success. I'm pretty sure I did not get the component values correct. I will
>> try the Roberts circuit again after I try the AS1 "electronics". I searched
>> for the AS1 schematic/detail but only found very general info on it. I
>> haven't "played" with this "stuff" for years but I feel a very strong
>> resurgence of interest in Seismology since I started this project again.
>> Thanks, Ed.
>>
>>
>>
>> On 9/17/2012 5:22 AM, chrisatupw@....... wrote:
>>
>>  Edward Ianni  
>> To: psnlist  
>> Sent: Mon, 17 Sep 2012 0:53
>> Subject: Old hobby resurgence
>>
>> Hi all:
>>
>> I have two very old seismometers and I would like to extend their
>> "periods", electronically and EXTERNALLY if that is possible. I tried this
>> a long time ago but I am not heavy into electronics and could not come up
>> with the right values for some of the circuits that I looked at. The two
>> Seismometers are a Kinemetric SH1 "Intermediate"(about 5 second period),
>> and a Sprengnether (square box type) with a 1.5 second period. Is it
>> possible to do this easily and is there a circuit somewhere with relatively
>> simple instructions for calculating component values? Thank You. Ed.
>>
>>
>>
>> Hi Ed,
>>
>>     The short answer is Yes !
>>
>>     You can extend the period of a seismometer electronically by about
>> x10 with two stages of the parallel Robert's circuit, or you can use the
>> simpler serial type used in the AS-1. So the Sprengnether could easily go
>> out to 15 seconds and bring in the surface waves fairly respectably. I
>> suggest that you extend the SH1 only to about 25/30 seconds and this is a
>> bit more difficult since you may have to suppress 1/f noise. You have the
>> problem with requiring a 1/f^2 amplifier characteristic and this gain has
>> to go to periods beyond what you require and the excess 1/f noise has to be
>> filtered out.
>>
>> Regards,
>>
>> Chris Chapman
>>
>>
>>
>
>
>
Hi Ed,

=C2=A0 Amaseis also has the inver= se filter which can only be used on SAC files, so you can still try out inv= erse filtering on event files.

=
Bob
<= div>

On Mon, Sep 17, 2012 at 1:10 PM, Edward Ianni <edwianni1@...........> wrote:
=20 =20 =20
Hi Bob;
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Good to hear from you. I am using Amas= eis and was looking for a simple circuit to hang on the back of the Seismometer (like the Black Box apparently has within it, to extend the period(s). I tried "Roberts's", years ago, but did not want to "= ;insert/inject" it into the existing circuit, thus the desire to "hang" som= e electronics directly behind the seismometer(s) to increase their periods. Thanks, Ed.

On 9/17/2012 9:45 AM, Bob McClure wrote:
Hi Ed,

=C2=A0 Software is available for period extension. Please no= te the following letter from Larry.

Bob


date: Tue, Feb 7, 2012 at 1:11 AM
subject: Robert's circuit and new WinQuake / WinSDR releases

Hi Everyone,

Last year I incorporated Bob McClure's inverse filter into WinQuake and WinSDR. See http://sites.google.co= m/site/bobmcclure90/inversefilter for more information on Bob's filter. You can try the filte= r in WinQuake if you install this beta release:


And if you have a PSN ADC board you can use the filter in real-time by using the current WinSDR beta release available here:

Please Note! In WinQuake the pendulum frequency is entered in seconds so a 4.5 Hz geophone would be entered as 0.222. In WinSDR the frequency is entered in Hertz, so a 20 second Lehman would be entered as .05. I should normalize this, I'm just not sure if I should change WinQuake or WinSDR...

In WinQuake the inverse filter can be found in the Time-Domain Filter dialog box and in WinSDR the Channel Settings -> Integrate / Filter tab dialog box.

A few days ago there were some emails on the list regarding what numbers to use for the pendulum frequency and high-pass filter. The pendulum frequency is the undamped period of your sensor. If you have a geophone this would normally be 4.5 Hz (WinSDR, .222 in WinQuake) or maybe 1 if you gave a 1 Hz geophone or AS1 type of sensor. This number sets where the filter starts to boost the lower frequencies to compensate for the drop off of sensitivity below the period of the sensor. The high-pass filter sets how much you want to extend the period of the sensor. It should be set to some number below the period of the sensor. Depending on the sensor and electronics, mainly the first op-amp, you might be able to extend the period by one decade.

Before adding the software filter to WinSDR and WinQuake I played around with the Robert's circuit. My results regarding using this filter, both in hardware and software, can be found here: http://www.seismicnet.com/epf/

Below is some information on the event files on my system that use this filter in WinSDR:

*.LCSV1.psn - This is a volume set from a Kinemetrics SV-1 5-Second intermediate-period vertical sensor. The LCZS1 channel is the raw data from the sensor. The LCZS2 channel has been period expended to 25 seconds (.04Hz) and then a 2 pole 2 Hz low-pass filter is applied to the data. This helicoder plot (updated every 5 min) http://www.seismicnet= ..com/quakes/images/lczs2.png shows the 24 hour graph from this channel. Teleseismic events show up much better on the inverse filter channel then the raw data channel.

*.LC45v.psn - This is a volume set from a horizontal 4.5 Hz geophone. The LCEG1 channel is the raw data from the sensor and the LCEG2 channel has been period extended to 5 seconds or .2 Hz. This PSN event file
http://www.seismicnet.com/quakes/1201/12012= 6.021845.lc45v.psn is a good example of an earthquake recorded from this sensor.

I would like to thank Bob McClure for supplying the Visual Basic code so I could add this feature to my programs.

Regards,
Larry Cochrane
Webtronics
=3D=3D=3D=3D

On Mon, Sep 17, 2012 at 9:22 AM, Gerald Payton <jerry@...........> wrote:

You may find your info at:=C2=A0 http://www.jclahr.com/sc= ience/psn/roberts/index.html

Regards,=

Jerry

=C2=A0

Fr= om: Edward Ianni [mailto:edwianni1@...........]
Sent: Monday, September 17, 2012 5:52 AM
To: psnlist@..............
Subject: Re: Old hobby resurgence

=C2=A0

Hi Chris;
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 I see that you are sti= ll giving out great information and advice. Could you possibly " point" me to the schematic of the serial AS-1 period "extender". As I recall I built the = Roberts circuit years ago with limited success. I'm prett= y sure I did not get the component values correct. I will try the Roberts circuit again after I try the AS1 "electronics". I searched for the AS1 schematic/detail but only found very general info on it. I haven't "played" with this &qu= ot;stuff" for years but I feel a very strong resurgence of interest in Seismology since I started this project again.=C2=A0 Thanks, Ed.



On 9/17/2012 5:22 AM, chrisatupw@....... wrote:

Edward Ianni <edwianni1@...........>
To: psnlist <psnlist@..............>
Sent: Mon, 17 Sep 2012 0:53
Subject: Old hobby resurgence

Hi all: =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0

I have two very old seismometers and I would like to extend their "periods", electronically and EXTERNALLY if that is possible. I tried this a long time ago but I am not heavy into electronics and could not come up with the right values for some of the circuits that I looked at. The two Seismometers are a Kinemetric SH1 "Intermediate"(about 5= second period), and a Sprengnether (square box type) with a 1.5 second period. Is it possible to do this easily and is there a circuit somewhere with relatively simple instructions for calculating component values? Thank You. Ed.=

=C2=A0

Hi Ed,

=C2=A0=C2=A0=C2=A0 The short answer is Yes ! <= /p>

=C2=A0=C2=A0=C2=A0=C2=A0You can extend the period of a seismometer electronically by about x10 with two stages of the parallel Robert's circuit, or you can use the simple= r serial type used in the AS-1. So the Sprengnether could easily go out to 15 seconds and bring in the surface waves fairly respectably. I suggest that you extend the SH1 only to about 25/30 seconds and this is a bit more difficult since you may have to suppress 1/f noise. You have the problem with requiring a 1/f^2 amplifier characteristic and this gain has to go to periods beyond what you require and the excess 1/f noise has to be filtered out.=

Regards,

Chris Chapman<= /span>

=C2=A0





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