The digital signal processing revolution began around 1980 as the first dedicated digital signal processors began to appear. Since that time DSP has been incorporated into just about every aspect of modern electronics. Oscilloscopes are no exception. Digital storage oscilloscopes have almost totally replaced analog oscilloscopes. They use DSP in acquisition modes, averaging, interpolation, display, bandwidth enhancement filters, optical reference receivers, mask testing, measurements, waveform math, FFT spectral analysis, and other applications. This paper discusses various attributes of bandwidth enhancement, optical reference receivers, and interpolation. The application allows current oscilloscope technology to obtain bandwidths up to 15 GHz.