New triggering system and signal processing in digital oscilloscopes

The authors have developed a 200-M sample/s digital oscilloscope that realizes the multigate triggering function and incorporates a 32-b RISC-(reduction-instruction-set-computer-) type processor and a floating-point coprocessor to execute various functional calculations and to display data on the screen. They describe a unique waveform triggering system (multigate triggering) and discuss the implementation and applications of a RISC-type processor for sophisticated signal processing functions. Multigate triggering is a real-time qualifying system that enhances the conventional level-crossing trigger. In digital oscilloscopes the digitized data are prestored in acquisition memory before the trigger occurs. In multigate triggering these prestored data are used by the digital comparator array for selecting the desired waveform. The RISC-type processing system has realized fast and accurate computations, including the Hilbert transform and digital filtering.<>