英语翻译1 IntroductionTHE USE of conventional,unsymmetrical ampl

英语翻译
1 Introduction
THE USE of conventional,unsymmetrical amplifier circuits in
biomedical engineering is very limited,because of their inadequacy
in suppressing power-line interference.Because one of
the patient electrodes is directly connected to the amplifier
signal ground and the other is a high impedance point,the interference
current flows only through the grounded electrode.The
grounded electrode impedance voltage drop is amplified and
leads to circuit saturation or masking of the useful biopotential
signal.
Many biosignal acquisition devices could benefit from the
use of only two electrodes.Electrocardiogram monitoring in
intensive care wards,ambulatory monitors,defibrillators etc.
are among the most common examples.
The most widely used technique for biosignal amplification
is based on an instrumentation amplifier first-stage design,
because of its ability to suppress the common mode interference
(NEUMAN,1998).In two-electrode instrumentation,the
amplifier inputs must have a differential impedance that is as
high as possible to avoid signal attenuation.On the other
hand,the amplifier should have reasonably low common
mode impedance,to create a path for the common mode interference
currents without significant voltage drop,keeping both
inputs in their specified operating voltage range.
THAKOR and WEBSTER (1980) introduced a bootstrapped
input stage.However,it has an inductive common mode
input impedance,resulting in a very poor common mode
input current range,especially for higher frequencies.
A circuit for a two-electrode,non-differential amplifier
was developed (DOBREV,2002),the performance of which isquasi-equivalent to the differential amplifier described by
DOBREV and DASKALOV (2002).Because the body as signal
source is floating and,in addition,the modern biopotential
amplifiers are isolated,it is possible to drive actively one of
the electrodes to the circuit common potential and thus to
balance the flowing interference currents.
Now,a very simple,low-cost circuit of a two-electrode nondifferential
amplifier is suggested,where the interference
current balancing is achieved by one operational amplifier
(OA) and two parallel RC networks.

翻译质量可保证,不过太长了,
1 Introduction
1.引言
THE USE of conventional,unsymmetrical amplifier circuits in biomedical engineering is very limited,because of their inadequacy in suppressing power-line interference.常规的不对称放大器电路在生物医学工程中的使用是有限的,因为它们在抑制电力线路的干扰上存在不足之处.Because one of the patient electrodes is directly connected to the amplifier
signal ground and the other is a high impedance point,the interference
current flows only through the grounded electrode.因为病人的电极中有一个直接连接到放大器信号接地,另一个是高阻抗点,所以干扰电流只流过被接地的电极.The grounded electrode impedance voltage drop is amplified and leads to circuit saturation or masking of the useful biopotential
signal.该接地电极阻抗的电压降被放大,并导致电路饱和,或者对有用生物电位信号的掩蔽.
Many biosignal acquisition devices could benefit from the use of only two electrodes.很多生物信号采集装置可以通过仅采用两个电极而得到好处.Electrocardiogram monitoring in intensive care wards,ambulatory monitors,defibrillators etc.
are among the most common examples.在重症监护病房中的心电图监控、门诊监测器、除颤器等是最常见的例子.
The most widely used technique for biosignal amplification is based on an instrumentation amplifier first-stage design,because of its ability to suppress the common mode interference
(NEUMAN,1998).最广泛使用的生物信号放大技术是基于一种仪表放大器的一级设计,因为它能抑制共模干扰（Neuman,1998）In two－electrode instrumentation,the
amplifier inputs must have a differential impedance that is as high as possible to avoid signal attenuation.在双电极仪器应用中,放大器的输入必须有尽可能高的差分阻抗,以避免信号衰减.On the other hand,the amplifier should have reasonably low common mode impedance,to create a path for the common mode interference
currents without significant voltage drop,keeping both inputs in their specified operating voltage range.另一方面,放大器的共模阻抗应该合理地低,以便为共模干扰电流创造一个通路而不致有明显的电压降,从而将两个输入都保持在它们规定的工作电压范围内.
THAKOR and WEBSTER (1980) introduced a bootstrapped input stage.However,it has an inductive common mode input impedance,resulting in a very poor common mode
input current range,especially for higher frequencies.Thakor和Webster（1980）引入了一个自举（bootstapped）输入级,产生了很差的输入共模电流范围（特别是在较高的频率下）
A circuit for a two-electrode,non-differential amplifier was developed (DOBREV,2002),the performance of which isquasi-equivalent to the differential amplifier described by DOBREV and DASKALOV (2002).Dobrev于2002年开发了一种用于双电极、无差动放大器的电路,其性能准-等效于Dobrev和Daskalov（2002）所描述的差分放大器.
Because the body as signal
source is floating and,in addition,the modern biopotential amplifiers are isolated,it is possible to drive actively one of the electrodes to the circuit common potential and thus to
balance the flowing interference currents.因为作为信号源的人体是浮动的,而且现代的生物电位放大器是隔离的,所以有可能主动地将电极中的一个激励到电路的公共电位,并因此来平衡流过的干扰电流.
Now,a very simple,low-cost circuit of a two-electrode nondifferential
amplifier is suggested,where the interference current balancing is achieved by one operational amplifier
(OA) and two parallel RC networks.现在人们提出了一种很简单而又廉价的双电极、无差动放大器的电路,其中,干扰电流的平衡是靠一个运算放大器（OA）和两个并联的RC（阻容）网络实现的.