Krohn-Hite 3323

The Krohn-Hite 3323 is a digitally tuned, dual-channel variable filter delivering precision signal conditioning across 0.01 Hz to 99.9 kHz. Each isolated channel operates independently with selectable low-pass, high-pass, band-pass, and band-reject configurations. Engineers configure cutoff frequencies via three decade switches and a six-position multiplier, achieving 24 dB/octave attenuation per channel or 48 dB/octave when cascaded. The instrument delivers maximum attenuation exceeding 80 dB to 100 kHz, with pass-band gains of 0 dB or 20 dB and output impedance of 50 ohms.

Technical Specifications

Channels: 2 (isolated, independent power supplies and connectors)

Cutoff Frequency Range: 0.01 Hz to 99.9 kHz (low-pass, high-pass, band-reject)

Band-Reject Null Operation: 0.01 Hz to 10 kHz

High-Pass Upper 3 dB Point: Approximately 1 MHz

Attenuation Slope: 24 dB/octave per channel; 48 dB/octave (cascaded same mode)

Maximum Attenuation: >80 dB (to 100 kHz); 60 dB at 1 MHz

Pass-Band Gain: 0 dB (unity) or 20 dB (gain of 10)

Maximum Output Voltage: ±7 V peak (0 dB gain to 500 kHz); ±0.7 V peak (20 dB gain to 500 kHz); ±3 V peak (20 dB gain at 1 MHz, open circuit)

Maximum Output Current: ±70 mA peak (to 500 kHz); 30 mA peak (at 1 MHz)

Output Impedance: 50 ohms

Hum and Noise: <0.5 mV RMS (100 kHz bandwidth); 2 mV RMS (10 MHz bandwidth); 2–5 mV RMS (X100 band, high-pass mode)

Output DC Stability: ±1 mV/hour; ±1 mV/°C

Distortion: <0.1% (typical across range)

Calibration Accuracy: ±2%

Filter Response: Four-pole Butterworth (maximally flat) or four-pole RC (damped)

Maximum AC Input Voltage: ±1 V peak (0 dB gain); ±0.7 V peak (20 dB gain)

Maximum DC Input Voltage: ±100 V

Input Impedance: 10 ohms

Key Features

Dual isolated channels enable parallel or series cascading for band-reject or band-pass operation

Selectable RC or Butterworth response optimizes for time-domain or frequency-domain performance

Decade-switch tuning with multiplier provides direct frequency setting without lookup tables

Low output impedance (50 ohms) drives high-impedance loads and distribution networks

Typical Applications

Audio and vibration signal conditioning

Precision measurement preprocessing

Multi-channel test signal filtering

Transient-optimized filtering (RC mode) or flat-passband filtering (Butterworth mode)

Compatibility & Integration Dual isolated channels with independent connectors integrate into rack systems and bench setups. ±100 V DC maximum input rating accommodates transducer outputs and signal sources across industrial and laboratory environments.