A dual-output, coherent signal generator using direct digital synthesis

This paper reports the design, performance and applications of a prototype low-cost, dual-output signal generator in which the two outputs are synchronised but may be set to different frequencies and/or different relative phase. The instrument uses direct digital synthesis (DDS) for each output and, under microprocessor control, provides convenient numerical (keypad) selection and readout of frequency and phase. A modest performance specification was set to suit the use of low-cost components and to meet, in the first instance, educational and demonstration requirements