A high performance digital receiver for home-built nuclear magnetic resonance spectrometers

The design and construction of a high-performance, low-cost, and easy to assemble quadrature digital receiver for a home-built nuclear magnetic resonance (NMR) spectrometer is described. Critical synchronization and timing issues are considered and solutions are discussed. The performance of the receiver is compared to that of a modern commercial NMR spectrometer. Advantages of this system include excellent passband flatness and delay flatness, very sharp filter cutoff, high dynamic range, bandwidths up to 30 MHz, and perfect balance between the quadrature channels with no component matching or adjustment.