Re: What exactly is a Gradient Amp ???? help please
December 31, 2006 11:30
Hello Mss. Lynette
Gradient amplifier is a system which amplifies the signals that comes from the spectrometer and pulse sequenceer and send them to a coil that is inside the main magnet to create the frequency resolution.
Re: What exactly is a Gradient Amp ???? help please
January 01, 2007 11:33
More simply explained, Lynette -
A gradient amplifier in essence is nothing more than a high powered audio amplifier. In fact some of the earlier MRI's used amps made by Crown (Techron), a popular industrial audio amplifier mnaufacturer of concert PA systems and such used in rock concerts and other events. Instead of driving voice coils against magnets like a speaker to reproduce sound, the coils a gradient amplifier pulses are locked in place ( usually in some type of epoxy or fiberglass ) and the pulses driving through them are used to do 3 things (because there are 3 axis). They are slice select, frequency encode (also refered to as read), and phase encode. The knocking sounds you hear are actually from the effect of the magnetic field's interaction with air. If the magnet is off you will not hear any knocking sound.
In short, think of it as a VERY high powered audio amp, like 5000 watts and up.
Regards, Dave
Re: What exactly is a Gradient Amp ???? help please
January 02, 2007 05:26
very well explained by DAVE, i may add the whole system of gradients and magnet is a giant speaker, you got the magnet and audio coil ( gradient coils x,y, and z) and the audio frequency, pulsed to the coils at high amplified power makes the speaker noize. as a matter of fact we injected the output of a radio into the gardient amplifier input and had the magnet singing.
jim
calscam medical
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Lynette Hendrix
What exactly is a Gradient Amp ???? help please
December 31, 2006 05:11
I need to know exactly what a gradient amp is and what it does ....can anyone please help me ? Thanks Lynette
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Bagher Mahdavi
Re: What exactly is a Gradient Amp ???? help please
December 31, 2006 11:30
Hello Mss. Lynette
Gradient amplifier is a system which amplifies the signals that comes from the spectrometer and pulse sequenceer and send them to a coil that is inside the main magnet to create the frequency resolution.
Best
Bagher
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Dave Adams
Re: What exactly is a Gradient Amp ???? help please
January 01, 2007 11:33
More simply explained, Lynette -
A gradient amplifier in essence is nothing more than a high powered audio amplifier. In fact some of the earlier MRI's used amps made by Crown (Techron), a popular industrial audio amplifier mnaufacturer of concert PA systems and such used in rock concerts and other events. Instead of driving voice coils against magnets like a speaker to reproduce sound, the coils a gradient amplifier pulses are locked in place ( usually in some type of epoxy or fiberglass ) and the pulses driving through them are used to do 3 things (because there are 3 axis). They are slice select, frequency encode (also refered to as read), and phase encode. The knocking sounds you hear are actually from the effect of the magnetic field's interaction with air. If the magnet is off you will not hear any knocking sound.
In short, think of it as a VERY high powered audio amp, like 5000 watts and up.
Regards, Dave
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James Fower
Re: What exactly is a Gradient Amp ???? help please
January 02, 2007 05:26
very well explained by DAVE, i may add the whole system of gradients and magnet is a giant speaker, you got the magnet and audio coil ( gradient coils x,y, and z) and the audio frequency, pulsed to the coils at high amplified power makes the speaker noize. as a matter of fact we injected the output of a radio into the gardient amplifier input and had the magnet singing.
jim
calscam medical
to rate and post a comment