Abstract: A triggerable, pipelined 40-bit high speed accumulator includes trigger and continuous modes which can be operated at 50 MHz clock frequency. The high speed accumulator can be combined with static random access memory (SRAM) so as to be applied to digital frequency synthesizer, function generator and arbitrary waveform generator, etc. The high speed accumulator has two operation modes-trigger mode and continuous mode. Under trigger mode, the accumulator waits for a trigger signal to initiate its operation, while under continuous mode, the accumulator works without any trigger signal.