Bill Johnson, Yakima WA
OK, you caught me. And it is about time I puzzled you - you have been
puzzling me since the first RVT exam.
First, I will say, I did not make up the story. My son reacted pretty
consistently to CW ultrasound. It puzzled me then, and I have never had
an explanation that made sense, except that CW delivers energy. The
only auditory manifestation since his birth that I have noticed is his
inability to listen to me, and as his parent, I assume this is not
He loves Hip-Hop but listens to "my" music as well - a lot of '60s stuff
and a lot of folk music. He must have learned to like the "oldies" when
he was turning me off and it was the only other thing to hear.
No, there was only one Doppler being used at a time. But I like your
spunk at trying to solve this problem logically.
If memory serves me, the Medsonics name change was a trademark issue
with a pacemaker maker. But my memory goes out of service occasionally.
I posted the story, waiting to see if any of our netters would realize
that your explanation involved PW Doppler and my story involved CW
Doppler, and first drafted the email to send to you offline, but as I
thought about it I realized it might be educational for all of us. You
have made it so, as you usually do. I only wish I had your explanation
22 years ago, it would have convinced my wife since physics was not her
If anyone knows the emoticon for "tongue in cheek" please let me know.
Oh, there are a few among you who have met my son Westin. He was lying
in a basket under the Hospitality table at the SNIVT meeting in San
Francisco in 1985. Time flies.
From: UVM Flownet [mailto:[log in to unmask]] On Behalf Of K. Beach
Sent: Friday, April 07, 2006 3:04 AM
To: [log in to unmask]
Subject: Re: Fetal memories
I'm still a little puzzled.
I'll guess that the midwife used a Medsonics or Medasonics FP3A Doppler
Fetoscope (Medsonics changed their name to Medasonics about that time
legal reasons that I never understood). This device was an obstetrical
version of the "pocket rocket" that was commonly used for fetal
monitoring. I'm confident that this was a CW Doppler operating at 3 MHz
(I'm guessing from the 3 in the model number). Because it was CW, there
is no Pulse Repetition Frequency to bang on the ear.
I searched on the WEB for "dog whistles" and found "The Acme Silent Dog
Whistle produces ultra high frequencies in the range of 5800Hz. to
12400Hz." with an audible example that you could play through your
computer speakers. Another site said "Typically, a dog whistle is
the range of 16000 Hz to 22000 Hz with only the frequencies below 20000
audible to the human ear." Note that your computer sound card probably
samples at 44,000 Hz so the Nyquest frequency is 22,000 Hz, the highest
frequency that cna be correctly recorded and played. The computer card
was probably designed for dog whistles.
Here is the only explanation that I can think of. Both you and the
midwife had fetal Dopplers, hers (or his, can a man be a midwife? Is my
assumption sexist?) and yours. Hers was transmitting at 3.000 MHz and
yours was transmitting at 3.001 MHz, a 1 KHz difference. Because of the
nonlinear sound propigation in the tissue and amniotic fluid, two
additional frequencies were generated, 6.001 MHz, the sum frequency and
0.001 MHz = 1 KHz) the difference frequency. The fetus was hearing the
difference frequency, when the two transmitted ultrasound sound beams
So how did this fetal experience affect your son's taste in music?
On Tue, 4 Apr 2006, Johnson, Bill wrote:
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