Study On Weak Signal Amplification And A/D Conversion Method Based On Chaos

The weak signal detection technique is the process of extracting weak signalthrough the use of electronics, information theory, computer and physics series ofmethods.Through some new technologies and new ways improve the signal to noiseratio of the detection system. As the signal is very weak, it must be magnified beforemeasured.Operational amplifier is the main reason for the introduction of weaksignal detection noise,so the noise figure of the preamplifier in weak signal detectionrequirements as small as possible.Furthermore chose the appropriate detectionmethod is very important.The traditional weak signal detection method mainlyincludes:correlation detection method,dual de-noising method,spectral analysis inthe frequency domain and so on.Using these methods to detect weak signalsgenerally require a higher threshold of signal to noise ratio. Due to the limitations oftraditional detection methods and the need for weak signal detection is increasinglyurgent,finding a new weak signal detection method become the hot topic now, wherechaotic, stochastic resonance, harmonic wavelet in weak signal detection has openedup a new way of thinking.Firstly, this paper designs a kind of weak signal cycle amplification circuit.Thecircuit is mainly composed of a main amplifier, two sample and hold circuit andanalog switch.By controlling the switching achieve weak signal cycle amplifying.The process is error self-compensation.Through the mathematical the weak signalcircuit is feasible through the method of mathematical formulas. Calculate the deviceparameters and give the results.Secondly, this paper design A/D conversion circuit based on chaotic theory.Theoutput of main amplifier compared zero potential and then output0or1, at the sametime input the reference voltage (V Ror V R) by controlling the analog switch for thenext comparison.So the cycle output symbol sequence.Establish correspondencebetween the input signal and the output sequence by the use of symbolic dynamicstheory.and then detect the weak signal.Simulation analysis of circuit system usingPSPICE software,mainly includes the selection of operational amplifier, sample andhold circuit and analog switch devices,besides, test some of its performance Thecycle amplifying circuit andA/D conversion circuit chaos is verified by simulation.Finally, put forward hardware design scheme, Including:the selection ofFPGA,power circuit design, amplification and A/D conversion circuit design.Using the verilog HDL language write the time sequence logic program in Xilinx ISEdevelopment environment and give simulation results.