When maximum performance is demanded from communications systems, test equipment, or any other frequency sensitive systems it is imperative to get the point where the filter response is -3dB (the breakpoint of the low pass filter placed exactly right. Placing the breakpoint correctly insures minimum distortion in the pass band, while yielding maximum attenuation of unwanted frequencies in the stop band. This is very hard to do in multiple frequency systems because when the break frequency is placed correctly for one task, it is usually by definition,