Adaptive dynamic range receiver for MRI

A receiver for a magnetic resonance imaging device, comprising:

• amplifiers with respective gain factors and inputs connectable to a resonance signal source and respective outputs;
• a respective analog-to-digital converter (ADC) connected to said respective output of each of said amplifiers, each said ADC generating a respective digital output;
• a respective multiplication/decimation filter connected to each ADC to receive said respective digital output, each multiplication/decimation filter being configured to extract a respective baseband signal from a respective one of said digital outputs to generate a respective baseband output;
• each of said respective multiplication/decimation filters being configured to demodulate a respective one of said digital outputs by numerically multiplying it by a signal from a numerical frequency generator;
• and
• a digital signal processor configured to select a one of said respective baseband outputs for output to an imaging system such that quantization noise in said digital output is a minimum fraction of said digital output and such that the ADC corresponding to said one of said digital outputs is not over-ranged thereby.

A method of digitizing an analog signal, comprising:

• receiving the analog signal along a plurality of channels;
• amplifying the signal along each channel with a respective gain;
• converting each amplified signal into a digital signal, to provide a plurality of digital signals;
• down-converting each of the plurality of digital signals to provide a plurality of down-converted digital signals;
• selecting a one of the down-converted digital signals having a lowest distortion;
• and
• correcting for lack of phase coherence and differing gain in said down-converted digital signals respective to each of said channels, whereby one of said digital signals remains normalized with respect to others of said digital signals when said others are selected.