Frequency Sweep, Field-Frequency Stabilized, Double Resonance Spectrometer

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Abstract
A description is given of circuits which improve both the performance and the versatility of a high resolution nuclear magnetic resonance spectrometer. Separate channels are provided for stabilization of the field-frequency ratio, for irradiation of any resonance, and for observing the spectrum in the frequency sweep mode. To maintain the operating frequencies of the observation and irradiation channels in constant proportion to the stabilization channel, all signals are derived from a single frequency synthesizer system. Essentially modular equipment is described to stabilize the base line and to isolate the receiver from the transmitter by the time sharing technique. The design and construction of a solid state (integrated circuit), field-frequency stabilizer is discussed in detail. Finally, the design of a stable audio frequency sweep oscillator, built from a voltage-to-frequency converter, is described along with a device for periodic repetitions of the sweep.