A general purpose differential digital modulator implementation incorporating a direct digital synthesis method

1993 ◽  
Vol 39 (4) ◽  
pp. 383-389 ◽  
Author(s):  
C.S. Koukourlis ◽  
P.H. Houlis ◽  
J.N. Sahalos
Keyword(s):  
Synthesis Method ◽  
General Purpose ◽  
Direct Digital Synthesis ◽  
Digital Synthesis

A Method on Realizing Signal Generator for Arbitrary Waveform

2013 ◽  
Vol 333-335 ◽  
pp. 661-665
Author(s):  
Deng Rong Zhou ◽  
Yu Rong Zhou ◽  
Jian Chun Gong ◽  
Da Xing Chen
Keyword(s):  
High Speed ◽  
Synthesis Method ◽  
Sine Wave ◽  
Waveform Generator ◽  
Direct Digital Synthesis ◽  
Waveform Data ◽  
Field Programmable ◽  
Digital Synthesis ◽  
Arbitrary Waveform ◽  
Hardware Circuit

The basic approach of generating arbitrary waveform is the digital synthesis method. Appling this method, one first samples and quantifies a period of the signal waveform to be generized, memorizes the obtained binary waveform data in a memory, and then reads it via hardware circuit in certain sequence, converts the data via digital-to-analog (DA) circuit, finally output the analog waveform through a filter. In this work, an arbitrary waveform generator (AWG) is designed based on the theory of direct digital synthesis (DDS)[1-7]and on the analysis of the performance of the output signal. The design uses a field programmable-gate-array (FPGA)[3]chip to utilize the AWG. The preset and display of the output frequency and phase are controlled by a micro computer unit (MCU). The artribary waveform data can be downloaded and updated from a communication interface. The AWG can produce a high-resolution arbitrary waveform. The dissertation focuses on hardware circuit design, which has been accomplished, including power supply module, MCU system, high-speed DA converter, and filter, etc. The experimental prototype of the AWG has been made and tested systemly.At the end of the dissertation, the measurement result of the system is given and its error is analyzed. It is shown the AWG can output a sine wave, a triangle wave, a sawteeth wave, or a square wave within the frequency range from 0.01Hz to 15MHz with the step of 10mHz, or output an arbitrary waveform within the range from 0.01Hz to 20kHz.

An Improved Doppler Shift Simulation Method Based on Third-Order DDS

2014 ◽  
Vol 614 ◽  
pp. 356-362 ◽  
Author(s):  
Rui Li ◽  
Yuan Long Cai ◽  
Xin Bei Bai ◽  
Ming Quan Lu
Keyword(s):  
Doppler Shift ◽  
Dynamic Range ◽  
Doppler Frequency ◽  
Simulation Method ◽  
Global Navigation Satellite Systems ◽  
Direct Digital Synthesis ◽  
Third Order ◽  
Satellite Systems ◽  
Digital Synthesis ◽  
Global Navigation Satellite

A method to simulate the Doppler frequency shift of high dynamic signals of Global Navigation Satellite Systems (GNSS) is provided in this paper. The methodology of the method based on third-order Direct Digital Synthesis (DDS) is introduced and the efficient implementation architecture is proposed. The design criteria of the DDS are investigated according to the precision and dynamic range of the Doppler shift. The simulation results are also demonstrated, which indicate that the method is available for the high precision Doppler shift simulation of GNSS signals.

Simulation of Stepped-Frequency LFM Radar Echo Based on FPGA

2012 ◽  
Vol 198-199 ◽  
pp. 948-953
Author(s):  
Jian Ping Ou ◽  
Sheng Qi Liu ◽  
Wei Niu
Keyword(s):  
Moving Target ◽  
Direct Digital Synthesis ◽  
Implementation Framework ◽  
Radar Echoes ◽  
Radar Echo ◽  
Digital Synthesis ◽  
Physical Simulations ◽  
Stepped Frequency ◽  
Logic Resource

An implementation framework of stepped-frequency LFM (SF-LFM) radar echoes simulator is presented in the paper based on the decomposition and calculation of SF-LFM radar echoes of a moving target. The proposed method can be implemented conveniently with direct digital synthesis (DDS) logic resource. The feasibility of this resolution is verified with computer and semi-physical simulations experiments.

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