Single-frequency lasing in monolithic crystals of holmium-thulium-doped YLF (Ho,Tm:YLF) is reported. A maximum single-frequency output power of 6 mW at a wavelength of 2.05 microm is demonstrated. Frequency tuning is also described.

Least-squares slne-flt algorithms are used extensively in signal processing applications. The parameter estimates produced by such algorithms are subject to both random and systematic errors when the record of input samples cor_Ists of a fundamental sine wave corrupted by harmonic distortion or nolse. The errors occur because, in general, such sine-fits will incorporate a portlon of the harmonic distortion or noise into their estimate of the fundamental. Bounds are developed for these errors for least-squares fourparameter (amplitude, frequency, phase, and offset) slne-fit algorithms. _e errors ere functions of the number of periods in the record, the number of samples in the record, the harmonic order, and fundamental and harmonic amplitudes and phases. The bounds do not apply tO cases in which harmonic components become aliased. This work wa_ supported by the United States Deparlment of Energy under lntroductlon Conlr_ct DE-AC _4-94AL_ 50n0.

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A high accuracy sampUng voltmeter, designed to span thefrequency range of 10Hz to 200 MHz, is described. The instrument operates autonomously, at a measurement updaterate of at leastoneper second. A novel quasi-equivalent time sampUng process is used, with a custom strobed comparatoras the sampUng device and decision element The architecture and control are presented, along with the timebasedesignprinciples.Major error sources associated with the time-base are also discussed.