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Δ-ΣA/D转换技术及在地震勘探中的应用 被引量:6
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作者 袁子龙 李婷婷 《地球物理学进展》 CSCD 2004年第2期300-303,共4页
 Δ调制型A/D转换技术是Δ-ΣA/D转换技术的基础.本文阐述了Δ调制型A/D转换器的基本原理,对信噪比和Δ-ΣA/D转换器的噪声成形作用进行了分析与推导,深入探讨了Δ-ΣA/D阶次、信噪比及采样率之间的关系,并由此得出结论:当代遥测地震...  Δ调制型A/D转换技术是Δ-ΣA/D转换技术的基础.本文阐述了Δ调制型A/D转换器的基本原理,对信噪比和Δ-ΣA/D转换器的噪声成形作用进行了分析与推导,深入探讨了Δ-ΣA/D阶次、信噪比及采样率之间的关系,并由此得出结论:当代遥测地震仪采用24位四阶Δ-ΣA/D转换器是高分辨率地震勘探精度的基本要求(瞬时动态范围或信噪比为120dB). 展开更多
关键词 A/D转换器 △调制采样率 采样 信噪比 噪声成形
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A 5mW 1.8V Low Over-Sampling Ratio ΣΔ Modulator with 81dB Dynamic Range 被引量:2
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作者 徐栋麟 赵晖 +2 位作者 王照钢 任俊彦 闵昊 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第1期12-18,共7页
This work demonstrates that the ΣΔ modulator with a low oversampling ratio is a viable option for the high-resolution digitization in a low-voltage environment.Low power dissipation is achieved by designing a low-OS... This work demonstrates that the ΣΔ modulator with a low oversampling ratio is a viable option for the high-resolution digitization in a low-voltage environment.Low power dissipation is achieved by designing a low-OSR modulator based on differential cascade architecture,while large signal swing maintained to achieve a high dynamic range in the low-voltage environment.Operating from a voltage supply of 1.8V,the sixth-order cascade modulator at a sampling frequency of 4-MHz with an OSR of 24 achieves a dynamic range of 81dB for a 80-kHz test signal,while dissipating only 5mW. 展开更多
关键词 ∑△ modulator low over sampling ratio low power low voltage
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Spectral Calculation of the Output Voltage of an Inverter with Bipolar Pulse Width Modulation
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作者 Mreela V. Sunde Z. Beneie 《Journal of Energy and Power Engineering》 2010年第8期48-56,共9页
Converters with pulse width modulation are used for connections between the direct current (DC) and alternating current (AC) networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for power... Converters with pulse width modulation are used for connections between the direct current (DC) and alternating current (AC) networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for powering induction furnaces, in audio technique. Spectrum of signals sampled by pulse amplitude modulation and output voltage spectrum of the converter with pulse width modulation have similar properties. Spectrum of signals sampled by pulse amplitude modulation contains a harmonic of frequency equal to the frequency of the modulating signal and the harmonics of frequencies equal to the sum of frequency of the modulating signal and multiples of the sampling frequency. The output voltage spectrum of the converter with bipolar pulse width modulation contains harmonic of frequency equal to the frequency of the modulating signal and harmonics of frequencies equal to sum of the frequency of the modulating signal and multiples of the frequency of the carrier signal. It also contains harmonics of frequencies equal to the sum of the multiples of the frequency of the modulating signal and the multiples of the carrier signal. The comparison analysis was carried out for the harmonics of the output voltage of the converter with bipolar pulse width modulation in time domain. The dependency of the amplitudes and frequency spectrum on the wave forms of the carrier signal and modulating signal was shown. Similarity of the output voltage spectrum of the converter and signal spectrum sampled by the pulse width modulation was also shown. Key words: Output voltage converter with bipolar pulse width modulation, spectral analysis, Fourier series, carrier signal, reference signal. 展开更多
关键词 Output voltage converter with bipolar pulse width modulation spectral analysis Fourier series carrier signal referencesignal.
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