Design of bessel low pass filter in direct digital synthesizer 直接數字合成器中貝塞爾低通濾波器設計
Through the research of direct digital synthesizer ( dds ) used as a divider in phase lock loop ( pll ) , a frequency synthesizer with small frequency resolution ratio and high purity frequency spectrum can be realized 摘要通過對直接數字合成器在鎖相環路中作為分頻器應用的研究,使頻率合成器可以在實現超細頻率分辨率的同時達到高的頻譜純度。
This paper studies the system and hardware design of the arbitrary waveform generator based direct digital synthesizer in detail . and a theoretical analysis of the system performance is also given 本文主要研究了基于直接數字合成( directdigitalsynthesizer )技術的任意波形發生器( arbitrarywaveformgenerator )的整體方案和核心部分的硬件設計。
The developed module are the arbitrary waveform generator based on dos ( direct digital synthesizer ) technology as a signal source of testing system and the common testing device such as virtual spectrum analyzer - , virtual digital storage oscilloscopes virtual frequency counter etc 所開發的模塊有,采用dds技術實現的任意波形發生器作為測試系統中的信號源,以及常見的信號測量設備,如虛擬頻譜分析儀,虛擬數字存儲示波器,虛擬頻率計數器等虛擬儀器。
This paper deals with fundamental principles and characters of direct digital synthesizer ( dds ) , analyzes the principle of dds in modulation , also presents various basic schemes to implement gmsic 4dqpsk and qam , and makes an initial analysis on their performances 本文介紹了直接數字頻率合成( directdigitalsynthesizer , dds )的基本原理及特性,分析了dds用于調制的原理,并給出了實現gmsk 、 / 4dqpsk和qam等調制的多種方案,同時對其性能進行初步分析。