为了满足大动态范围、高精度、低噪声地磁数据采集的发展需求,采用一种24位Σ-Δ型ADC7192用于三路数据采集的方法。该方法通过使用可编程增益阵列调理交流放大部分减小了整体电路规模和功耗。针对野外等特殊应用场所引入二次数字(模拟...为了满足大动态范围、高精度、低噪声地磁数据采集的发展需求,采用一种24位Σ-Δ型ADC7192用于三路数据采集的方法。该方法通过使用可编程增益阵列调理交流放大部分减小了整体电路规模和功耗。针对野外等特殊应用场所引入二次数字(模拟)电源、自校准、满量程校准和ADC内部滤波器,降低其噪声的同时又抑制了50 Hz工频干扰。后期硬件测试对采集数据进行了对比分析,功耗为4.35 m A、测量精度可达70μG的技术指标。展开更多
Delta Scuti stars are variables of spectral types A to F with a pulsation period less than 0.3 days and light variation amplitudes smaller than 0,8 and mostly less than 0 02 mag. in V band. In the history, they have b...Delta Scuti stars are variables of spectral types A to F with a pulsation period less than 0.3 days and light variation amplitudes smaller than 0,8 and mostly less than 0 02 mag. in V band. In the history, they have been called by some one as dwarf Ceipheids, ultra-short period Cepheids or AI Vel type and Delta Scuti type. Rcently some of them with lower metal Content and higher space velocity are called as SX Phe type varial ies. In this artical we give a general review on these types of variables. At first we give out some statistic results of them by using the catalogue of P.Lopez et al. published in AApSS 83(1990), 51-69 and other sourse.Those are the period distribution, the period-amnlitude and the rotational; velocity. We also give out the period variations by using our own observations and other's collected in the years between 1980 to 1992 for 18 stars (28 And, GP And, BS Aqr, CY Aqr, YZ Boo, BL Cam, AD CMi, VZ Cnc, XX Cyg, RS Gru, DY Her, KZ Hya, EH Lib, SZ Lyn, HD 79889, ZZ Mic, DY Peg, SX展开更多
<正> Chaos is universal phenomenon in the nature. Some scientists think that chaos theory is the third revolution in physics of this century, following relativity theory and quantum mechanics. The δSct type sta...<正> Chaos is universal phenomenon in the nature. Some scientists think that chaos theory is the third revolution in physics of this century, following relativity theory and quantum mechanics. The δSct type stars are pulsating variable stars with light amplitudes in Ⅴ from 0~m.003to 0~m.9 and periods from 0~d.01 to 0~d.2. The spectral types are A0-F5Ⅲ-Ⅴ. Some stars such as ρ Puppis and AD CMi show light curves which repeat beautifully from cycle to cycle.The light curves of many stars, especially the small-amplitude variables, often appear vari-展开更多
文摘为了满足大动态范围、高精度、低噪声地磁数据采集的发展需求,采用一种24位Σ-Δ型ADC7192用于三路数据采集的方法。该方法通过使用可编程增益阵列调理交流放大部分减小了整体电路规模和功耗。针对野外等特殊应用场所引入二次数字(模拟)电源、自校准、满量程校准和ADC内部滤波器,降低其噪声的同时又抑制了50 Hz工频干扰。后期硬件测试对采集数据进行了对比分析,功耗为4.35 m A、测量精度可达70μG的技术指标。
文摘Delta Scuti stars are variables of spectral types A to F with a pulsation period less than 0.3 days and light variation amplitudes smaller than 0,8 and mostly less than 0 02 mag. in V band. In the history, they have been called by some one as dwarf Ceipheids, ultra-short period Cepheids or AI Vel type and Delta Scuti type. Rcently some of them with lower metal Content and higher space velocity are called as SX Phe type varial ies. In this artical we give a general review on these types of variables. At first we give out some statistic results of them by using the catalogue of P.Lopez et al. published in AApSS 83(1990), 51-69 and other sourse.Those are the period distribution, the period-amnlitude and the rotational; velocity. We also give out the period variations by using our own observations and other's collected in the years between 1980 to 1992 for 18 stars (28 And, GP And, BS Aqr, CY Aqr, YZ Boo, BL Cam, AD CMi, VZ Cnc, XX Cyg, RS Gru, DY Her, KZ Hya, EH Lib, SZ Lyn, HD 79889, ZZ Mic, DY Peg, SX
文摘<正> Chaos is universal phenomenon in the nature. Some scientists think that chaos theory is the third revolution in physics of this century, following relativity theory and quantum mechanics. The δSct type stars are pulsating variable stars with light amplitudes in Ⅴ from 0~m.003to 0~m.9 and periods from 0~d.01 to 0~d.2. The spectral types are A0-F5Ⅲ-Ⅴ. Some stars such as ρ Puppis and AD CMi show light curves which repeat beautifully from cycle to cycle.The light curves of many stars, especially the small-amplitude variables, often appear vari-
