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So let's get started with shimming.
In our spectrum window we see the signal position is close to 1000 Hz.
We'll need to adjust its position so it appears in the frequency range of
+200 to +500 Hz.
We can move the signal by adjusting the transmit frequency.
Since the signal appears at approximately +900 Hz
and I would like it to be closer to +200 Hz
I need to add 700 Hz to the transmit frequency.
So I'll need to change the 4th decimal place, therefore I'll change my current
TX frequency of 44.14957 MHz
to 44.15027 MHz.
Then I'll execute the autoShim script by clicking "Start Run".
Let's zoom into the signal by adjusting the "min and max frequency to plot" values
from +/-2000 Hz
to +/-1000 Hz.
let's execute you audition skirt once more
it looks like we've done a good job position their signal close to the
target of two hundred hurts
now the summer instrument
telecheck to test from box
navigate to the start run button click it
well our instruments should make
let's examine the information scrolling buying the text window at the bottom
first we see a series of initialization parameters
such as bandwidth incident destination
sample period enough i_d_ duration ample sequencer action
the pair of legs just below these data fields displace the initial korle values
which the ocean script will adjust
the relaxed or equilibrium spectrum peak height appears on the second line
this values discarded from evaluation
datians settings will be adjusted by the audition script by some factual amount
of the increments step sizes we indicated in the linear in quadratic
increment parameter fields above
to sign the size of the step taken is within our initial parameter value how
the steps eisenstein urge us it is determined by the simplex algorithm
after evaluation of the spectrum thi chi
this information is repeated after every poll sexy cute intervention ming
the sequence of lines below the spare repeat session value aspect repeat rate
information
but now includes a third line indicating the processing of data is completed and
that the script is waiting for the remainder of the t one delay before
excuse in the next pulse
the time between pulses is determined by the t one recovery delay
and all fourier transform processing in data transferring from the instrument to
the web browser user interface
must be completed within the t one time frame
the second series of data indicates the beginning of the evaluation phase of the
audition script
this spectrum peter is a starting point
and it is the value were trying to improve upon
when an improvement in this values achieved the audition script retains the
corresponding coal oil values
assigns associate spectrum peter it is the new best value
and continues to explore in that direction
we can keep track of the scripts progress by monitoring the best spectrum
p trade value
which appears after each iteration
when we perform a full sham we optimize the three linear five quadratic shin
coils
and for any given iteration of the simplex algorithm they're up to a
possible coral adjustments or cycles
however i never tear approximately two point five cycles per your rationing
you can see in the example of this behavior between iterations twenty four
and twenty seven
we're only one quote just the preparation was made
let's check the progress of russian so far
we started as a spectrum p kind of approx more four hundred fifty five
thousand
and now or at approx missed one in seventy eight thousand after thirty year
rations
for my instrument the goal is to relax but competetive around five hundred
fifty thousand
if we choose to abort the script right now
the best values obtained so far would be written to the sham electron x
the shin premarin user interface feel would open up
and the new optimize values
would replace the old shin values
is important to note that shin values will only be overridden
it's an improvement has been made during the execution of the audition script
if one manually justice in value as an excuse to notion script
questioning his advice to set the maximum number of iterations to one
hundred
and to allow the audition scripts to run to completion
while boarding the auction script early has advantages
such as when the best possible optimize shin has already been achieved prior to
reaching the maximum number of iterations
one runs a risk in a boarding the script too early
issue advantage to allow the auditions trip
to run to completion
returning to the scrolling tax let me comments on the information contained in
the line processing complete
when executing out of the audition or one poll scraps
the fourier transform into complex data acquired is performed during the t one
delay
if we want to assist the valuation of the spectrum peak height
we need to make sure all data processing is completed within thirty one delay we
sat
if a process time extension occurs
the exciter protons will have a relaxed further and the signal intensity will
potentially be larger
and that compare a bill to other pulses
processing time is affected by the number of points we acquire
by the maximum time the plotting and by the back some points a plot parameters
for shinning thirty-one delay should be set to eight seconds
acquisition points to one thousand
maximum points plot can be set to its maximum value one thousand points and
the maximum time to plot
can be set to its maximum value of two hundred fifty milliseconds
selling these values properly will prevent the script from experiencing
process extension delays
now the ceo shin script is completed let's evaluate our f eight d inspection
first let's take note of the optimize specter pete item five hundred twenty
five thousand
that's pretty good value for my cartridge
recall that our goal is approximately five hundred fifty thousand
so what's different
the lower signal intensity after shipment has to do with the fact that
the protest signal is not a fully relaxed want
remember
we're pulse in the arabs oil every eight seconds
all water protons enough fully relax back to their equilibrium magazine issue
within that time period
so long as the recycle time between pulses this fix
we don't have to wait for the protons to fully relax when we sham
if we weighed about thirty seconds after the audition script ends our water
protons will hopefully relax bhakti librium
and if we execute a test run
to spectrum peak height we obtain will be compare both to the test report value
yes i do looks quite good
it has the appearance of the slowly damp sine wave
d_f_ i_d_ displays here only the real or absorp tive component of the complex
data in the time-domain
when we sham
we're trying to make homogeneous magnetic field volume around the i_r_s_
oil
within which is our sample
as we improve the magnetic field homogeneity
our signal become stronger and the signal decay rate slows
we can see half i d that at two hundred fifty milliseconds we still have about
fifty percent of our signal intensity
more signal intensity we have
the betters are shim
and that is what we're trying to chief election
fourier transform complex data produces a spectrum of our signal in the
frequency domain
when monitoring our spectrum
we look for some a tree in our signal as well as intensity
signal resolutions determined by many factors both instrumental and chemical
and listening we improve our signal resolution insensitivity by maximizing
the intensity and minimizing the asymmetry of our signal
let's finish our shinning procedure by saving action values to file
if we click the aboard run button
or the audition scriptures run to completion
the shins user interface will appear
the caesar face will not appear unless there's an improvement in the shin
currents
that's navigate to the shame name field the providers file name that is the
script of our sham
i'd like to use my initials
mega temperature
and cereal value in case i want to save other shin files today
by clicking the save button asian values will be written to a file which will be
stored on our instrument
we can access this file by navigating to and clicking the files button
this was the files page
scrolling down to the shins section we can see the file we just saved
i can access this file like liking it
wants a page refreshes we can see our states shin values
we now have the option to download the file for storage on our computer by
clicking the download shin splint
the file is now in the download rec room a computer and we can open a like any
other text file
we can also choose to leak decision file by clicking the delete decent spot
i mean the select no in this case
or we can reload mission values into the rampage user interface by clicking to
use the shins that run button
this will automatically open the run page
and make the shins active for whichever script was use last
and in our case this would be the audition script
if i executed test run station premise will be written to the ship electron ics
overwriting previously stored values
but in this case the the sanction values has since we just save them to this file
since has been at least thirty seconds
the specter peak height we obtained is a relaxed value
anthem parable to the test report
our goal was to achieve a value of five and fifty thousand
and after she made with a five hundred fifty-four thousand
tissue nishant and ready to go
the main mission the procedure described here uses very robust settings that will
work in all cases
if your instrument is left power down all the time annisten it rarely
you may find that you get the same results was a quicker procedure
where you only had just three grady actions x_y_ and z_
and only run thirty forty or fifty iterations
you do this by setting the linear recommends to zero point zero zero two
the quadratic increments to zero point zero
and the maximum iterations two fifty
if you get into the habit of gradient only shimmy be sure to still run the
full make mission atleast weekly
or whenever the unit has been moved or the power has been cycles
in this video we explored the topic of shinning using the audition script
we describe various parameters their meeting an optimum values for shamik
we examined the texas played in the scrolling text window
as well as the time in frequency domain plots
efi sommelier with the system you'll find they keep your unit indigenous very
simple
you just love the audition strip
justice center frequency and had to start run button
remember there is a detailed description of the summing process and system
maintenance section of the deepest and forty-five user manual
under the heading titled shipment
this documentation is located on the documentation section of the support
page of our website
w_w_w_ dot peterson dot com
both html d f versions of the documentation available