A Guide for Signal Processing of Sensors and Transducers Himanshu Dehra American Institute-Industry Forum on Energy 1-140 Avenue Windsor, Lachine, Québec, H8R 1P7 Canada Introduction The gastrointestinal tract, the lungs, the kidneys, and skin make exchange of materials and energy between the internal and the external environments. A steady state is achieved by regulatory mechanisms involving the balance between the inflow and outflow of the internal environment that stabilizes the composition of the internal environment [1]. The tendency to regulate the internal environment so that it is maintained in a steady state is called homeostasis. Our bodies have feedback systems that regulate our internal environment. The feedback systems make use of storage depots and numerous feedback loops. The monitoring of plasma calcium is a good example of negative feedback. The bones constitute large storage depots for calcium, for the plasma to withdraw these storage supplies in times of need. Our body’s homeostatic regulatory systems are represented by feedback loops. The feedback is considered negative, when it is compensating or negates any change. The negative feedback is essential to stabilize a system. The objective of the paper is to present an analogy for signal processing of our sensory organs, our communications through speech, our written words, and our associated pictures. The circuit analysis and synthesis for sensory organs of a human body is achieved by analog mixed-signal circuit design of a parallel plate photovoltaic amplifier [3, 6]. The logic NOT gate for a parallel plate photovoltaic amplifier is a source, sink matrix inverse constituting noise filters that offers immunity to the internal environment. A parameter that is closely related to the logic 0 and logic 1 levels is the noise margin. Noise Filters The noise filters are classified as per source signal of unwanted frequencies from solar power, electric power, light power, sound power, heat power, fluid power and fire power [5]. An acoustic filter is an electrical analog circuit of various combinations of RC feedback circuit with an operational amplifier and is used to filter unwanted frequencies of oscillations from a power system [4]. It is a network with selective transmission for currents from a power system of varying frequency. The unwanted frequencies generated from a power system are removed by using an operational amplifier with different combination of filter arrangements. An operational amplifier is an integrated circuit that consists of several bipolar transistors, resistors, diodes, and capacitors, interconnected so that amplification can be achieved over a wide range of frequencies [4]. The action of filtering the frequency from a power system is based on the variation in the reactance of an inductance or a capacitance with change in frequency [4]. The band of frequencies that can be removed from a power system can be at the low frequency end of frequency spectrum, at the high frequency end, at both ends, or in the middle of the spectrum. The filters to perform each of these operations are known respectively as low-pass filters, high-pass filters, band-pass filters and band-stop filters [4]. There are many configurations of design of filters. The filters are divided into passive and active configurations. The passive filters are less effective simple circuits constructed with resistors, capacitors, and inductors. The active filters are useful in providing an effective filtering action than passive filters. The active filters require a source of operating power. The criteria for definitions of filters for noise filtering is based on areas of energy stored in a wave due to noise interference, speed of wave and difference of power between two intensities of