A high-power, untuned radio-frequency transmitter for pulsed nuclear magnetic resonance spectroscopy.

Abstract

A gated radio-frequency transmitter suitable for pulsed nuclear magnetic resonance spectroscopy is described. It has a wide frequency response (3 dB from about 20-50 MHz) and can deliver pulses of greater than 900 v peak to peak into 180 Ω resistive loads with rise and fall times of less than 01 μs. The circuitry described includes a gated radio-frequency mixer-amplifier with two variable phase inputs, and a gated radio-frequency power amplifier. The gating circuits used are d.c. coupled throughout to prevent droop in long pulses and interaction between the pulses.