function Elec = AA_AI_filters()
Elec = containers.Map;
[z,p,k] = butter(3,2*pi*1e4,'low','s');
Elec('Analog_AA') = zpk(z,p,k);
Elec('Digital_AA') = zpk(z,p,k);
Elec('Analog_AI') = zpk(z,p,k);
Elec('Digital_AI') = zpk(z,p,k);