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-wenkub
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【正文】 C. S., Voulgaris N. C., “A Digital Method for Sinewave Generation.” Archiv fur Electrotechnik, 72, pp 327, (1989). [6] Koukourlis Chr. S, Trigonidis V. K., Sahalos J. N., “Differential Synchronous Demodulation for Small Signal Amplitude Estimation.”, IEEE Instrumentation and Measurement, 42, No. 5, pp 926, (1993). 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) 關(guān)鍵詞 : DDS。 the voltage can be adjusted by tuning the PWM dutyfactor. The system output three PWM signals, which controls AD9850 output extent, dutyfactor and the output extent of DAC0832, respectively,. Fig. 3 shows the PWM controls DA transferring circuit. Fig. 3 PWM controlled DA converting circuit Fig. 4 Export amplification and the wave filtering circuit. (a) amplification circuit。 M accumulated step length of phase register, constant。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。 MCU。 Signal generator。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。 f out output sine wave frequency, unit: Hz。 (b) filtering circuit Amplification and wave filtering circuit The amplification circuit will export amplified wave form and modify the factor of amplification. An excellent smooth output waveform can be achieved by using the lowpass active power filtering. The amplification circuit and the filtering circuit is showed in Fig. 4. Software design And the system software mainly include AD9850 driving module, DAC0832 driving module, the stepbystep automation module, PWMconvertingDA module and uC/GUI figure supporting system implanted in procedure. The operation interface is full of humanization for the multiwindow pattern is adopted. The design process of the system software is shown in Fig. 5. Implanted uC/GUI The numerical control signal source has used the uC/GUI software sufficiently to establish many windows and control buttons. By means of invoking the corresponding windows and control with the feedback information, the peripheral equipment operated under the control of the system. The external equipment is mainly separated into two drivers, the drive being an AD9850 module and DAC0832 module drive, respectively. The two modules can be controlled by means of the outside interruption and timing interruption. AD9850 Drive AD9850 has 40 control words, among them, 32bit is used for frequency control, 5bit is used for the phase control, 1bit is used for the power source dormancy control, 2bit is used to choose operation pattern. Fig. 5 Systematic procedure flow chart This 40 control words may arrive at AD9850 by concurrence way or serial way, in the concurrenc
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