The Models 3200 and 3202, illustrated in Figure 1, are solid
state variable electronic filters with cutoff frequencies
continuously adjustable over the frequency range from 20 Hz
to 2 MHz. The pass-band gain is unity (0 db), with an
attenuation rate of 24 db per octave outside the pass-band.
Maximum attenuation is greater than 80 db and the output hum
and noise is less than 100 microvolts.
The Model 3200 can function as either a High-Pass or
Low-Pass Filter. In the High-Pass mode of operation the
maximum input signal is 3 volts rms and the upper 3 db point
occurs >t approximately 10 MHz. In the Low-Pass mode the
Filter is direct-coupled and the combined ac plus dc input
signal should not exceed 4,2 volts peak.
The Model 3202 consists of two Model 3200’s mounted in a
single cabinet isolated from each other with independent
power supplies, and input and output connectors. When these
wo filter channels are switched to the same mode of
operation and connected in series with both dials set to the
same cutoff frequency, the Model 3202 will function as a
High-Pass or Low^Pass Filter with an attenuation rate of 48
db per octave. If the two channels are connected in series,
and one channel is operated in the Low-Pass mode and the
other channel a the High-Pass mode, the Model 3202 will
function as a Band-Pass Filter with attenuation ' rate of 24
db per octave outside the pass-band.
When the two channels are connected in parallel, as
described in Section 2. 3, the Model ^202 will function as
either a Band-Reject Filter with cutoff frequency limits
from 20 Hz to 2 MHz or provide a sharp null at any frequency
between 40 Hz and 800 kHz.
This Filter has a maximally flat or Butterworth
characteristic when the RESPONSE switch(s), located on the
rear of the chassis, is in the MAX FLAT position. For
pulse-type waveforms this switch should be in the SIMPLE RC
position, optimum for transent-free filtering.