The Model 3103(H), illustrated in Figure 1, is a solid state variable electronic band-pass Filter with a low cutoff frequency range adjustable continuously from 10 Hz to 1 MHz and a high cutoff range from 30 Hz to 3 MHz. The pass-band gain is unity (0 db), with attenuation rate of 24 db per octave outside the pass-band, and a maximum attenuation of 80 db. Maximum input signal amplitude is 3 volts rms and output hum and noise is less than 150 microvolts. As shown in the Simplified Schematic Diagram, Figure 2, the Filter consists basically of an input amplifier, a variable low-pass section (high cutoff frequency), and a variable high-pass (low cutoff frequency) section all connected in series. Both cutoff frequencies are tuned capacitively in decade steps by the band multiplier switch, and continuously within each decade by the frequency dial which varies four cascaded resistorfilter elements. A response switchS 1 selects the desired filter characteristics.