Abstract: A channel propagation emulator includes a radio peripheral configured to receive input radio frequency (RF) data and modify the input RF data according to channel effects including signal delay, propagation loss and Doppler shift effect to generate an RF output, and a host device operably coupled to the radio peripheral. The RF output represents a modification of the input RF data based on a propagation model. The host device operably coupled to an external controller and is configured to define emulation parameters based on the propagation model. The propagation model is selected at the external controller. The external controller is configured to provide instructions for implementing the Doppler shift effect to include spreading that is multiplicative in frequency.

Abstract: The disclosed spark source is adapted to generate electrical sparks to produce light for spectroscopic analysis of materials placed on the spark gap electrodes or introduced into the sparks. The disclosed spark source comprises a high voltage transformer having a secondary winding for supplying alternating current at a high voltage, a storage capacitor, a charging circuit including a rectifier connected between the secondary winding and the capacitor for charging the capacitor, spark gap electrodes having a spark gap therebetween, a discharge circuit including an electronic switching device connected between the capacitor and the spark gap electrodes for discharging the capacitor across the spark gap and control means for supplying a sequence of variably spaced triggering pulses to the input means of the electronic switching device for producing a sequence of spark cycles in which the capacitor is charged to substantially the same voltage for all of the spark cycles.