The Model 3750 is a variable electronic filter that covers the frequency range from 0o 02 Hz to 20 kHz, and operates in any one of four functional modes; high- pass, low-pass, band-pass or band-reject. The mode of operation is selected by means of a front panel FUNCTION switch. The pass-band gain is unity (Odb) or 10 (20db), as selected by a front panel GAIN switch, with attenuation slopes of 6» 12, 18 or 24 db per octave* as selected by 2 front panel SLOPE switches. The cut-off frequencies of both the high-pass and the low-pass sections are independently adjustable from 0, 02 Hz to 20 kHz. Operation in the band-pass or band- reject modes permits passage or rejection of any band of frequencies between these limits. In the low-pass and band-reject modes, the filter is direct coupled, passing all frequencies from DC to the selected cut-off frequency of the low-pass section. In the high-pass and band-reject modes, the upper 3 db point is at approximately 1 MHz for 0 db gain, and approximately 200 kHz for 20 db gain. An optional battery kit {Part No. BK-37 5), consisting of four (4) rechargeable nickel-cadmium batteries, plus associated hardware, may be added at any time. In addition, an optional rack-mounting kit (Part No. RK-519), is available for installing the 3750 in a standard 19" rack spacing.