The Arbitrary Waveform Generator Based On SOPC

This subject has designed an arbitrary waveform generator equipment based onSOPC. The waveform generator uses the Cyclone device, and uses the directdigital frequency synthesis technique, which is DDS. The DDS signal generator acheivesthe function of output arbitrary waveform. And the embedded NOIS Ⅱ core could controlthe FPGA target hardware.The core module of the system is DDS, which is a digital direct frequency synthesizer.It constitute from the phase accumulator, waveform storage ROM, D/A converters andlow-pass filter. When the clock frequency is fixed, the output signal frequency determinesby the frequency word, the output phase is determines by the phase control word, andwhich one waveform to be chosen determines by waveform control word. The median ofthe frequency accumulator determines the frequency resolution, and the depth of the ROM,as storage points of the waveform, determines the phase resolution.In the hardware design, FPGA chip uses EP1C6, which comes from Altera’s CycloneI, and use the NIOS Ⅱ processor as the core integrates into the FPGA chip to build SOPCsystem. All these to form a flexible embedded system, and the system can option his ownperipherals. The design of peripheral circuits, including power supply circuit, the AD5424analog to digital conversion circuit, the serial circuit, the keyboard display circuit andexternal expansion SDRAM circuit. SOPC system, who can be designed differentfunctions to the waveform generators, has a custom peripherals function. That make itadapt to different environments, and improve system’s integration, else enhance thesystem’s anti-jamming capability. Coupled with the programmability of FPGA, fullyconfirmed the superiority of the SOPC.In the duration of the software design, firtly, the generator module can be realized inFPGA using VHDL programming language. On-chip rom stores commonly used fourwaves, they are sine wave, square wave, triangle wave and sawtooth wave. NIOS Ⅱ cernelcontrols these waves’s default values and steps of frequency and phase, and controlskeyboard to select output wave.