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Hi all,
I've never understood what he meant by 'Liebhazet' - I presume it is the
name of someone who first developed the method of beating two signals
together to get a beat?
Anyway ... I agree with George that a 22 Hz difference requires a BIG
difference in mag. field between the two sensors. My interpretation of this
sentence is that there were 22 beats observed in the whole decay cycle which
takes, say 10 seconds or so. That would give a difference of about two
beats per second or two Hz. This would still be much much larger than 0.1
nT difference. I've used a Dalton gradiometer and, as I've said so many
times before, it is very hard to tell the difference between, say, 1 beat
per second and 1.1 beat per second.
The whole method of using the beat frequency to measure mag. field
gradients was first proposed, I believe, by Aitken and Tate in 1962
following a suggestion by Waters and Francis, 1958. The first of these
references is cited in my long 56 page document.
Jim
----- Original Message -----
From: George Davidson
To: The Proton Mag Forum
Sent: Tuesday, April 18, 2000 6:55 AM
Subject: Re: Dalton Magnetometer theory
> The Proton Mag Forum
>
>
> Hi Proton Mag forum,
>
> Any idea how Liebhazet does brings in the beat frequency? They
> mention 22 "beats" in the 1975 text contributed by Dale. These
> cannot be Hz as 1Hz = bout 22 nT and they claim 0.1 nT res.
>
> George Davidson
>
>
> __________________________________________________ ____________________
I've never understood what he meant by 'Liebhazet' - I presume it is the
name of someone who first developed the method of beating two signals
together to get a beat?
Anyway ... I agree with George that a 22 Hz difference requires a BIG
difference in mag. field between the two sensors. My interpretation of this
sentence is that there were 22 beats observed in the whole decay cycle which
takes, say 10 seconds or so. That would give a difference of about two
beats per second or two Hz. This would still be much much larger than 0.1
nT difference. I've used a Dalton gradiometer and, as I've said so many
times before, it is very hard to tell the difference between, say, 1 beat
per second and 1.1 beat per second.
The whole method of using the beat frequency to measure mag. field
gradients was first proposed, I believe, by Aitken and Tate in 1962
following a suggestion by Waters and Francis, 1958. The first of these
references is cited in my long 56 page document.
Jim
----- Original Message -----
From: George Davidson
To: The Proton Mag Forum
Sent: Tuesday, April 18, 2000 6:55 AM
Subject: Re: Dalton Magnetometer theory
> The Proton Mag Forum
>
>
> Hi Proton Mag forum,
>
> Any idea how Liebhazet does brings in the beat frequency? They
> mention 22 "beats" in the 1975 text contributed by Dale. These
> cannot be Hz as 1Hz = bout 22 nT and they claim 0.1 nT res.
>
> George Davidson
>
>
> __________________________________________________ ____________________