PSN-L Email List Message

Subject: Re: My first Sensor
From: "Geoffrey" gmvoeth@...........
Date: Wed, 20 Sep 2006 23:03:29 -0700

Hello Ted;

The only thing I can add is that
below Frq:1Hz or Per:1Sec You usually use
Period which is seconds and above that
you use Hertz. You get an infinite range
between 1 and zero for period and
1 and infinity for CPS. But if you want
to do filter calculations I find using
only HZ works just fine. Use a calculator like
the TI 36X Solar or whatever programs
to help you with the filters. I can recommend
a filter ARRL filter program as well as
as LT Spice which are both free, or used to be,
also a spectra program to analyze your noise/filters.
! Hz or !sec is a kind of natural division point
between two worlds so to keep from getting
confused just use Hz if you do any calcs.
The formulas work quite well provided you
have the decimal places to work with (10 or more).
Do not round any intermediate calcs until you
get your final answers.

If your system is set up right then damping is probably
your troubles. But any motion you can see
with the naked eye should send your signal
into saruration and cutoff (clipping)
making a square wave. Overdriving the amplifier
makes good to get first time of arrival
but you cant really see anything else.

I read where Robert Kennedy Played games
with Mr. President (Johnson) not long before
he (R.Kennedy) was Assassinated by placing a
(assumed) ultra-sonic mechinism into a brief case
and holding it on his lap so no recording could
be made. I thing the mechanism he used
Jammed the microphones in the room
driving the preamp into a square wave
essentially deafining the recorders.
This upset the secret service to no end.
Or so i read. This was back in the Early 1960s.
The time of the Buffalo Springfield song
called "For What Its Worth"
Your system should be so sensitive
just blowing on it should drive it into

Good Luck.


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