In contrast to the general operational amplifier (op amp) noise model widely used, we propose a more complete and applicable noise model, which considers the correlation between equivalent input voltage noise source and current noise source . Based on the super-position theorem and equivalent circuit noise theory, our formulae for the equivalent input noise spectrum density of an op amp noise a...

This chapter is devoted to the realization of some novel active circuits by using transconductance amplifiers. The transconductance amplifier can be realized by the widely used device Op-Amp and specially designed operational transconductance amplifier (OTA). By using single Op-Amp in one circuit itself we can get two filter responses. The first circuit realizes first order low pass – high pass...

In this paper we have describes the design of current mode instrumentation amplifier (CMIA) for bio-signal Acquisition system. The current mode instrumentation amplifier technology is based on voltage mode operational amplifier (op amp) power supply current sensing technique. There are two design challenges of this topology. First one is the Op amp mismatch and second is precise current mirrors...

The current-conveyor has precise unity gain between Z and X (Fig. 1), rather than the high ill-defined open-loop gain of the voltage op-amp, therefore in amplifier applications the current-conveyor is generally used without any overall negative feedback. The advantage of this approach is that the traditional closed-loop gainbandwidth conflict of negative feedback voltage op-amp circuits is avoi...

This paper describes the design of Current Mode Instrumentation Amplifier (CMIA) for ECG signal Acquisition system. The CMIA topology is based on voltage mode operational amplifier (op-amp) power supply current sensing technique. Op amp mismatch and precise current mirrors are two design challenges of this topology. High Common Mode Rejection Ratio (CMRR) and Power Supply Rejection Ratio PSRR i...

In this work a low power, low voltage and high gain operational amplifier is proposed. For this purpose a negative resistance structure is used in parallel with output to improve the achievable gain. Because of using self cascode transistors in the output, the proposed structure remains approximately constant in a relatively large output voltage swing causing an invariable gain. To evaluate the...

This article is an excellent introduction to analog filters. It covers the basic first and second order filter types as well as the advantages and disadvantages of passive and active filters. It derives and analyzes the basic biquad implementation using several op amp implementation examples. The world of filter design is often thought of as black magic because of the myriad of configurations, ...

In recent years, Electrical Bioimpedance (EBI) methods have gained importance. These methods are often based on obtaining impedance spectrum in the range of β-dispersion, i.e. from a few kHz up to some MHz. To measure EBI a constant current is often injected and the voltage across the tissue under study is recorded. Due to the performance of the current source influences the performance of the ...