英语翻译数据的采样和保持当某一通道进行A/D转换时,由于A/D转换需要一定的时间,为了保证A/D转换的精度,必须在A/D

英语翻译
数据的采样和保持
当某一通道进行A/D转换时,由于A/D转换需要一定的时间,为了保证A/D转
换的精度,必须在A/D转换时保持该值不变.考虑到A/D转换的转换时间以及系统所允许的最大采样时间,在A/D转换前使用采样/保持电路,
采样/保持电路有采样和保持两个工作状态,受方式控制端的数字信号值控制.当方式控制端输入信号为“0"(低电平),开关K闭合,采样/保持电路处于采样状态,运算放大器A1输出电流经电阻R限流后给电容C充电,Vout也会跟随Vin的变化而变化;当方式控制端输入信号电平为高电平“1”时,电子开关K打开,由R和C组成的采样/保持电路就处于“保持”状态,输出端Vout保持Vin在K打开时的电平值.电容C的值对采样保持的精度影响颇大.电容C选的过大会影响VouT对V}的跟随特性,过小会使VouT在保持期间发生变化.因此,电路中采用运算放大器A1和A2,以提高输入阻抗和减小输出阻抗.

The sample of the data and keep
When the some passage carries on the conversion of A/ D,because the A/ D conversion needs certain time,for the sake of the assurance the A/ D turn
Accuracy of change,must at the A/ D convert keep and should be worth constantly.In consideration of biggest sample time that conversion time and systems of the A/ D conversion allow,in the A/ D before convert use the sample/ hold circuit,
Sample/ the hold circuit has sample and keeps two work appearances,being subjected to the numerical signal value control that the way control carry.When the way control carries to input the signal to"0"( the low electricity is even),the switch K shuts to match,sample/ the hold circuit is placed in to sample the appearance,the operation enlarger A1 refreshes for the electric capacity C after output the electric current was flow by the electric resistance R limit,the Vout also will follow behind the Vin variety but varietieses; be the way control to carry to input the signal electricity even is even for high electricity"1",the electronics switch K open,the sample/ hold circuit constitute by R and C is placed in to" keep" the appearance,outputting to carry the even value of the electricity that the Vout keeps the Vin to open in the K.The value of the electric capacity C is to the accuracy influence that sample keep rather big.The electric capacity C chooses over the conference to affect the VouT to the V} of follow behind the characteristic,lead small will make the VouT take place the variety during the period of keep.Therefore,the adoption operates the enlarger A1 and A2s in the electric circuit,to raise to input the resistance and let up the exportation resistance.