Patent ID: 7595697
Filing Date: 2009-09-29
Classification: G01R

Abstract:
1. A magnetic and radio frequency field tolerant amplifier for use in a time varying radio frequency field, said time varying radio frequency field having a predetermined frequency, said magnetic and radio frequency field tolerant amplifier comprising: an amplifier stage, said amplifier stage comprising a pair of differential input terminals and a pair of differential output terminals; a differential to single ended output amplifier stage, said differential to single ended output amplifier stage comprising a pair of differential input terminals and an output terminal, each of said differential input terminals of said differential to single ended output amplifier stage in electrical communication with a respective differential output terminal of said amplifier stage; and a delay line having a delay line output terminal and a delay input terminal, said delay line output terminal of said delay line in electrical communication with an input terminal of said pair of differential input terminals of said amplifier stage and said delay line input terminal of said delay line configured for connection to an input signal source, said input signal source having an input signal comprising a signal of interest and a component resulting from effects of a radio frequency field; wherein said delay line is configured to produce an 180 degree phase shift at the predetermined frequency in the component of said input signal resulting from the effects of the radio frequency field at said delay line output terminal to thereby cancel the component of the input signal resulting from the effects of the radio frequency field having the predetermined frequency and leave the signal of interest of the input signal substantially unaffected.