PSN-L Email List Message
Subject: Re: digital filtering
From: ChrisAtUpw@.......
Date: Thu, 2 Feb 2006 06:07:18 EST
In a message dated 02/02/2006, jonfr500@......... writes:
Hi all
I have started digital filtering my gif files online. With a lowpass
filter cutoff of 10Hz. Any suggestion on that move is welcomed by me,
since i am still learning on this.
Hi Jon,
Your amplifier Low Pass Filter is actually set to 20 Hz, so there should
be very little data above about 22 Hz. This should be well suited to you
local quakes.
Sorry that I got it wrong, but I was reading the characteristics from
the psn website.
Regards,
Chris Chapman
In a message dated 28/01/2006, lcochrane@.............. writes:
Chris wrote:
> The low pass filter on your amplifier board should be 10 Hz and have 8
> poles. In practice, a signal at 13.4 Hz will be reduced to 1/10 and one
at 18
> Hz to 1/100.
> The amplifier has a high pass filter set at 0.05 Hz = 20 sec., which
is
> well below the lowest response of your geophones.
Actually Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I
usually set the
filter to 20 Hz instead of the 10 Hz if I know that the filter board will be
used
with a geophone to record local events.
Regards,
Larry Cochrane
In a message dated 02/02/2006, jonfr500@......... writes:
<=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Hi=20
all
I have started digital filtering my gif files online. With a=20
lowpass
filter cutoff of 10Hz. Any suggestion on that move is welcomed=20=
by=20
me,
since i am still learning on this.
Hi Jon,
Your amplifier Low Pass Filter is actually set=20=
to=20
20 Hz, so there should be very little data above about 22 Hz. This should be=
=20
well suited to you local quakes.
Sorry that I got it wrong, but I was reading th=
e=20
characteristics from the psn website.
Regards,
Chris Chapman
=20
In a message dated 28/01/2006, lcochrane@.............. writes:
<=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Chris=20
wrote:
> The low pass filter on your amplifier board should be=
10=20
Hz and have 8
> poles. In practice, a signal at 13.4 Hz will be red=
uced=20
to 1/10 and one at 18
> Hz to 1/100.
> &nbs=
p;=20
The amplifier has a high pass filter set at 0.05 Hz =3D 20 sec., whi=
ch is=20
> well below the lowest response of your geophones.
Actually=
=20
Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I usually set t=
he=20
filter to 20 Hz instead of the 10 Hz if I know that the filter board w=
ill=20
be used
with a geophone to record local events.
Regards,
Lar=
ry=20
Cochrane
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