Magnetometer for detecting a magnetic field associated with nuclear magnetic spins or electron spins

A magnetometer for measuring a magnetic field associated with nuclear magnetic spins or electron spins, comprising:

• a measurement volume adapted to receive a specimen of a material that exhibits resonance selected from the group consisting of nuclear magnetic resonance and electron spin resonance, said material having a resonant frequency that is dependent on a magnetic flux density of a magnetic field, associated with the resonance, which is to be measured;
• a transmission device disposed for emitting a transmission signal into said specimen in said measurement volume at a selected transmission frequency having a frequency spacing from said resonant frequency;
• and
• a reception device disposed for receiving a mixed signal from said specimen containing mixed frequencies including the resonant frequency and the transmission frequency, said reception device filtering out said resonant frequency from said mixed frequencies in said mixed signal to obtain a filtered out signal which is representative of said magnetic flux density.