基于dds和單片機(jī)數(shù)字控制信號(hào)發(fā)生器的設(shè)計(jì)外文翻譯、中英對(duì)照、英漢互譯(已修改)
2024-11-26 16:04 本頁(yè)面
【正文】 Design of Digital Controlled Signal Generator Based on DDS and MCU Yinjun Chena, Zehuai Yuan Faculty of Electronic Information and Mechanical Electrical Engineering, Zhaoqing University, Zhaoqing 526061, China Keywords: DDS。 MCU。 Signal generator。 Phase Accumulator。 DAC Abstract. Its advantage to use DDS chip is output signal frequency bigger, and precision higher, But users can39。t change the output signal waveforms. The MCU can produce the required arbitrary waveforms, but its program execution of the order limit the we use their Synergy to design the digital controlled signal generator. The System has the advantage of output good quality waveform, frequency of precision and stability ,and high frequency, empty, amplitude and phase is to step into the need. Introduction The digitally synthesized sine waveform (Direct Digital Synthesis, DDS) is a wellknown method and has been applied to many embedded applications [1]. This technique can be used to create a positive digital sine waveform. Compared to other frequency posing method, Direct Digital Frequency Synthesis(DDS) has been the most popular trend in modern frequency synthetic technique for its excellent characteristics. The signal source that the DDS technology realizes can carry out accurate controlling on DDS frequency , extent , phase exporting wave form39。s etc. by numerical control circuit, the system making use of this method has many merits such as stability, reliably and accuracy. The mercial DDS chip can only export a sine wave for the data in the ROM form already has been solidified. If needing to e into being any wave form, it may e true by the way that FPGA adopts DDS IP core or hardware describe language etc, however,the cost of This way cost is high。 on the other hand, any wave form can be achieved by making use of micro controller unit (MCU) to carry out figure frequency bining and DA converting. The experiment and applying testing have shown that the numerical control signal source posed of STM32 micro controller and DDS chip can work well. DDS and wave form programming pattern The core of DDS system is phase accumulator carriage, and it is posed of a ADR and one unit phase register. When any clock es, the phase register increases by with the step length, phase register output and phase control word add together, and then the output is imported to sine inquiry form address. The sine inquiring form includes the numeral extent information of oneperiod sine wave, each address corresponds to the phase dot of 0~360 degrees of the sine wave. The mapping digital signal drives DAC and outputs analog value. The output sine circle and frequency are The phase register will return to the original state when the 2N/M fc clock is finished. Accordingly, the DDS system output a sine wave when the sine inquiring form finish a circle. The output sine circle and frequency is TO output sine wave circle, unit: s。 TC external referenced clock circle, unit: s。 M accumulated step length of phase register, constant。 f out output sine wave frequency, unit: Hz。 f c external referenced clock frequency, unit: Hz。 N phase accumulator digit, constant. The relationship among the frequency control word, and the output signal frequency and the referenced clock frequency are: Frequency control word is directly proportional to the output signal frequency. In order to describe clearly, the sine wave form is as one vector turns around phase circle, the phase circle matches along with a cycle sine wave. Every sampling pots in wave form corresponds to a phase dot of the phase circle. To synthesis the required frequency signal, it needs to acplish the follow
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