Krohn-Hite 3381 Electronic 8 Pole Filter 0.1Hz to 200kHz LP/HP

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The 3381 provides a tunable filter with a frequency range from 0.1 Hz to 200kHz.  The frequency response cahactreristic is selectable to either maximally flat (Butterworth) for clean filtering in the frequency domain or linear phase (Bessel) for complex filtering.

SKU: KH3381 Category: Tag:


  • Type: 8-pole, Butterworth/Bessel.
  • Attenuation Slope: 48dB/octave.
  •  Tunable Frequency Range fc: 0.1Hz to 200kHz; (option 002, 0.005Hz).
  • Frequency Resolution: 0.001Hz, 0.1Hz to 0.999Hz; 3 Digits, 1Hz to 200kHz, (option 002, 0.001Hz from 0.005Hz to 0.1Hz). 
  • Cutoff Frequency Accuracy: ±3%.
  • Relative Gain at fc: –3dB, Butterworth; –12.6dB, Bessel.
  •  High-Pass Bandwidth (0dB Gain): >2MHz. Stopband Attenuation: >80dB.
  • Wideband Noise (2MHz bandwidth detector): 0dB gain, <300 Vrms.  Max. gain, <25 Vrms RTI.
  •  Harmonic Distortion (1V  input, 0dB gain): –60dB (0.1%) to 10kHz; –50dB (0.3%) to 100kHz.
  • DC Stability: Typically ±1mV/ C.

Input: Differential or single-ended.    Pre-Filter Gain: 0dB, 10dB, 20dB, 30dB, 40dB, 50dB, ±0.2dB.    Impedance: 1M ohm in parallel with 25pf.    Maximum Input: ±10V peak at 0dB gain, reduced in proportion to gain setting.    CMRR: >60dB to 10kHz; >50dB to 100kHz.    Coupling: ac (0.16Hz) or dc.    Sensitivity: 3mV peak with 70dB total gain for 10V peak output.    Maximum DC Component: ±100V in ac coupled mode.

Output:    Post-Filter Gain: 0dB to 20dB in 0.1dB steps, ±0.2dB.    Maximum Voltage (open circuit):  ±10V peak.    Maximum Current: ±80mA peak.    Impedance: 50 ohms.    DC Offset: Adjustable to zero volts



Additional information

Weight 24 lbs
Dimensions 12 × 12 × 12 in

Model Number


Data Sheet