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Formulas are derived for the solution of the transient currents of dissipative low-pass T-type electric wave filters. Oscillograms taken by cathode ray oscillograph for d-c. and a-c. cases are found to agree with results calculated from these formulas. From these calculations, the following conclusions are derived. When terminating resistance is gradually increased from O, the damping constants of the sine terms begin to differ from each other, ranging in decreasing magnitude from term of the lowest frequency... Formulas are derived for the solution of the transient currents of dissipative low-pass T-type electric wave filters. Oscillograms taken by cathode ray oscillograph for d-c. and a-c. cases are found to agree with results calculated from these formulas. From these calculations, the following conclusions are derived. When terminating resistance is gradually increased from O, the damping constants of the sine terms begin to differ from each other, ranging in decreasing magnitude from term of the lowest frequency to the last term of cut-off frequency. Hence the transient is ultimately of the cut-off frequency. At cut-off frequency, this constant is near to but greater than R/2L. For each increase of section, there is introduced an additional sine term with smaller damping constant. Therefore transients die out faster in filters of smaller number of sections. Since transient amplitudes are of the same order of magnitude before and after cut-off, filtering property only exists in the steady states. 此篇先推求收端加电阻时,低频滤波器瞬流之公式。依此公式算出之图与用阴极光示波器映出之曲线相符合。自推算之结果,可得下列结论: (一)在滤波器收端电阻渐加时,瞬流各项之挫率渐互异,其数量由低频项至隔阻频之项顺序渐减;其最小数仍比收端无电阻时之挫率(R/2L)为大。故瞬流终必变为隔阻频之电流;而较收端无电阻时易于消减。 (二)当滤波器增加一段时,瞬流之项数亦加一。所加项之挫率皆比前有者为小。故少段滤波器之瞬流易于消减。 (三)在隔阻频後瞬流之数量与在其前者相彷恒较隔阻频後之安定数量大数十倍,故滤波之特性仅能见之于安定状态。 The assignment of the fundamental frequencies of C4H2 given by Timm and Mecke is discussed and a new assignment in accord with the selection rules is suggested. Nine force constants for the molecule are calculated according to Timm and Mecke's assignment, while the new assignment gives no reasonable constants for the deformation vibrations. Further study of the Raman spectrum and the infrared absorption is necessary for a final classification of the deformation frequencies. 按Timm Mecke之C_4H_2基本振动率,吾人求得一含有九个常动之势能式中各常数之值。 The circumferential vibration of a hollow quartz cylinder has been thoroughly studied. The empirical relation connecting the dimensions of the cylinder and the frequency of vibration has been formulated, and the temperature coefficients of the frequency determined. The temperature coefficient is practically zero for a wide range of temperature, when the ratio of the internal radius to the external radius of the cylinder approaches a value which is very close to 0.5. 以纯粹水晶割成空心圆柱,令圆柱之轴平行於晶体之光轴。于其里外二面,敷以铜质管状电极、置诸最简单之Pierce式振荡线路中,即能自生振动其振动之方式繁多,俱经吾人详细阐求,已在另文发表,茲不复赘。 各种振动方式中,以绕周振动发生最易。设圆柱内径与外径之比小于一去0.5极近之数,则绕周分三段而振动;设大于此数,则分六段而振动, 绕周振动之温度系数,亦经测定其法置圆柱於一特制之电炉中,连其二电极於振荡电路,令生振动。以所生高周率电流与一周率甚近之水晶片所生之高周率电流相干涉,由 是而生之低周率音差,复与一低周率振荡器相比较,若是则加热后圆柱振动周率之变化,可在该低周率振荡器上直接读之。 若是所得之结果绕周振动之温度系数,随其内外径之比而异。圆柱之绕周分三段而振动者,其温度系数常为正;内外径之比率增加,则温度系数减少。圆柱之线周分六段而振动者,其温度系数常为负;内外径之比率愈高,则温度系数愈大。惟适当三段振动告终六段振动肇端之时,则亘十馀度其周率几不以温度而变合二十馀度而平均计之其温度系数约为0.5... 以纯粹水晶割成空心圆柱,令圆柱之轴平行於晶体之光轴。于其里外二面,敷以铜质管状电极、置诸最简单之Pierce式振荡线路中,即能自生振动其振动之方式繁多,俱经吾人详细阐求,已在另文发表,茲不复赘。 各种振动方式中,以绕周振动发生最易。设圆柱内径与外径之比小于一去0.5极近之数,则绕周分三段而振动;设大于此数,则分六段而振动, 绕周振动之温度系数,亦经测定其法置圆柱於一特制之电炉中,连其二电极於振荡电路,令生振动。以所生高周率电流与一周率甚近之水晶片所生之高周率电流相干涉,由 是而生之低周率音差,复与一低周率振荡器相比较,若是则加热后圆柱振动周率之变化,可在该低周率振荡器上直接读之。 若是所得之结果绕周振动之温度系数,随其内外径之比而异。圆柱之绕周分三段而振动者,其温度系数常为正;内外径之比率增加,则温度系数减少。圆柱之线周分六段而振动者,其温度系数常为负;内外径之比率愈高,则温度系数愈大。惟适当三段振动告终六段振动肇端之时,则亘十馀度其周率几不以温度而变合二十馀度而平均计之其温度系数约为0.5×10~(-6)/C,小於寻常水晶片者五十馀倍。割制此种圆柱,并无繁难,且电极简单,装置便利以之控制振荡,校准周率,对无线电通讯,裨益实多也。
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