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Simulation results show that the Filter and VGA system has gain of 6~48 dB, variable gain of 42 dB,6 dB/Step, THD54 dBc at 100 mV peak-to-peak input voltage, IIP3 of-6.35 dBV. The NF is less than 25 dB and current dissipation is 30 mA from 1.8 V voltage supply.

电路的仿真结果表明滤波器和VGA系统的增益为6~48 dB，可变增益为42 dB，6 dB/step，在输入电压峰峰值为100 mV时THD小于-54 dBc，线性度为-6.35 dBV，噪声系数在通带内小于25 dB，消耗电流为30 mA。

7 To 3.3 V operating supply voltage 44.1 kHz sampling frequency 16.9344 MHz (384fs) system clock Built-in crystal oscillator circuit 16-bit, MSB rst, rear-packed serial data input format ( 64 fs bit clock) 8-times oversampling digital lter · 32 dB stopband attenuation ·+0.05 to -0.05 dB passband ripple Deemphasis lter operation · 36 dB stopband attenuation ·-0.09 to +0.23 dB deviation from ideal deem- phasis lter characteristics Attenuator · 7-bit attenuator (128 steps) set by microcontrol- ler Soft mute function set by parallel setting ·(approximately 1024/fs total muting time) Mono setting · Left or right channel mono selectable by micro- controller Built-in innity-zero detection circuit , two-channel D/A converter · 3rd-order noise shaper · 32fs oversampling Built-in 3rd-order post-converter low-pass lters 24-pin VSOP package Molybdenum-gate CMOS process

2.7至3.3 V工作电源电压为44.1千赫的采样频率16.9344兆赫（384fs）系统时钟内置晶体振荡器电路的16位，MSB在前，后包装的串行数据输入格式（64飞秒位时钟）8倍超采样数字滤波器·32分贝的阻带衰减·+0.05至-0.05分贝通带纹波去加重滤波器的运作·36 dB抑制频宽衰减·-0.09到0.23 dB的偏差认为不理想，症状困扰评估滤波特性衰减器·7位衰减器（128级）集由单片机在-莱尔软静音功能的平行设置·（共约1024/fs静音时间）单声道设置·左或右声道单声道微控制器可选的内置的无限零检测电路Δ，两通道的D / A转换器·第三阶噪声整形·32fs过采样内置三阶后转换器的低通滤波器24引脚VSOP封装钼栅CMOS工艺

Results Postoperative hearing threshold was 25 dB for speech frequencies with a gain of 47dB for the elder brother, and hearing threshold of 28 dB with a gain of 52 dB for the younger sister.

结果 兄语言频率气导听力提高47 dB，听阈为25 dB；妹提高52 dB，听阈为28 dB，分别随访8年及1年余，听力稳定。

Results The average value of the hearing threshold was 70.67±20.43 dB HL in group A and 67.58±36.18 dB HL in group B(P＞0.05)before treatment.The average value of the hearing threahold reduced to 30.09±20.43 dB HL in group A and 18.42±18.05 dB HL in group B(P＜0.05) after treatment.

结果 治疗前A组和B组的平均听阈分别为70.67±20.43 dB HL和67.58±36.18 dB HL(P＞0.05)，治疗后两组听力平均提高分别为30.09±20.43 dB和18.42±18.05 dB(P＜0.05)。

Pre-operative audiometric testing revealed a mean air conduction pure tone average of 51.93 dB and a mean bone conduction PTA of 23.17 dB. The mean post- operative air conduction and bone conduction PTA were 36.59 dB and 24.23 dB, respectively.

术前临床测试平均气导51.93 dB，平均骨导23.17 dB；术后平均气导36.59 dB，平均骨导24.23 dB，术前、术后骨气导差距分别为28.76 dB和12.36 dB，骨气导差距改善了16.40 dB，68%的病人骨气导差距缩小到20 dB以内，无听力下降者。

Pre-operative audiometric testing revealed a mean air conduction pure tone average of 51.93 dB and a mean bone conduction PTA of 23.17 dB. The mean post- operative air conduction and bone conduction PTA were 36.59 dB and 24.23 dB, respectively. The mean pre- and post- operetive air-bone gaps were 28.76 dB and 12.36 dB, respectively, with a gain of 16.50 dB. Sixty-eight percent of patients closed their ABGs to within 20 dB.

术前临床测试平均气导51.93 dB，平均骨导23.17 dB；术后平均气导36.59 dB，平均骨导24.23 dB，术前、术后骨气导差距分别为28.76 dB和12.36 dB，骨气导差距改善了16.40 dB，68%的病人骨气导差距缩小到20 dB以内，无听力下降者。

Pre-operative audiometric testing revealed a mean air conduction pure tone average of 51.93 dB and a mean bone conduction PTA of 23.17 dB. The mean post- operative air conduction and bone conduction PTA were 36.59 dB and 24.23 dB, respectively. The mean pre- and post- operetive air-bone gaps were 28.76 dB and 12.36 dB, respectively, with a gain of 16.50 dB. Sixty-eight percent of patients lunwen114closed their ABGs to within 20 dB.

术前临床测试平均气导51.93 dB，平均骨导23.17 dB；术后平均气导36.59 dB，平均骨导24.23 dB，术前、术后骨气导差距分别为28.76 dB和12.36 dB，骨气导差距改善了16.40 dB，68%的病人骨气导差距缩小到20 dB以内，无听力下降者。

With ILO-92 Otodynamics Analyzer,distortion product otoacoustic emissionsat the 2 f1-f2 frequency were recorded from 86 normally hearing ears in response to four groups of different primary levels (L1=L2=75 dB SPL ; L1=L2=65 dB SPL ; L1=L2=60 dB SPL ; L1=65 dB SPL , L2=50 dB SPL).The average DPOAEs-gram demonstrated a bilobed contour with two peaks at approximately 1.5 kHz and 5 kHz and a "notch" between 2.5 kHz and 3 kHz.Moreover,the contour of DPOAEs-gram had no obvious changes with sex,ear or primary stimulus levels differences.

利用耳动态分析仪ILO-92，对48例听力正常人(86耳)在4组不同原始刺激强度下(L1=L2=75 dB SPL；L1=L2=65 dB SPL；L1=L2=60 dB SPL；L1=65 dB SPL，L2=50 dB SPL)进行畸变产物耳声发射检查，结果发现平均DPOAEs图呈双叶型轮廓：在1.5 kHz和5 kHz附近，2 f1-f2 DPOAEs存在两个高峰，在2.5～3 kHz附近存在一个低谷，此图型结构无性别、耳别差异。

Results The mean value of DPOAE decreased from 41.3 dB to 13.7 dB after perfusion of fluid devoid of calcium ion, it revived to 36.7 dB after reperfusion with normal perilymphatic fluid.

结果 用无钙人工外淋巴灌流后DPOAE的均值从41.3 dB SPL降至13.7 dB SPL，再用正常钙浓度的外淋巴灌流后又可回升到36.7 dB SPL。

Noise can be reduced by about 2 dB by using oil-resistant rubber isolator to reduce solid-borne sound transmission; the setting-up of semienclosed noise barriers can not only reduce the work region's noise of workshop by 13 dB, but also adapt to the gas's characteristic involved with H2S, CO, and other poisonous components without supplied mandatory ventilation; locating the noise absorbers on the walls and ceiling of workshop can reduce noise by 8 dB; the exhaust silencer's elimination volume can reach above 30 dB which is designed in accordance with the exhaust noise spectrum characteristic of gas-combustion generator. By the combination of these measures, the noise of the gas- combustion generator will be under effective control, so that the gas power plant's noise pollution problems can be resolved.

通过选用耐油性好的橡胶隔振器减少固体传声，可降低噪声约2 dB；设置半封闭式机组隔声屏障可降低生产车间工作区域内的噪声达13 dB，并且适合瓦斯发电气源中含有H2S、CO等有毒有害气体的特点，不需增加强制通风措施；在生产车间四周墙壁和顶棚上敷设吸声体，最大可降低空间噪声8 dB；根据瓦斯发电机排烟噪声频谱特性设计的阻抗复合式消音器的消音量可以达到30 dB以上。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。