2-Channel 3 MHz Filter/Amplifier

Precision Filters’ Answer for Measurements of High Frequency Voltage up to 3.15 MHz

Designed for high frequency voltage measurements, the 28612 2-Channel 3 MHz Filter/Amplifier provides two channels of low noise programmable amplification and programmable low-pass or hign-pass filters with cutoff frequencies from 5 kHz to 3.15 MHz. Gain is programmable from x1 to x1000. Count on unsurpassed accuracy and channel to channel match for critical measurements. Up to sixteen 28612 cards may reside in the 28000 system to provide 32 channels per chassis.

The 28612 can be used to improve the signal-to-noise-ratio for high frequency measurements on resonant transduces and other sensors, particularly when large out-of-band energy limits the digitized dynamic range. When used as an anti-aliasing filter, the sharp selective response of the 28612 will maximize data bandwidth while providing greater than 80 dB attenuation of aliases. The 130 V per microsecond slew rate of the 28612 minimizes risk of distortion on high frequency edges of shock data. Excellent DC characteristics make the 28612 suitable for DC measurements, adding to the versatility of this amplifier.

The 28612-LP6FP card has a flexible high performance 6-pole low-pass filter characteristic that can be programmed for time or frequency domain measurements. The FLAT mode characteristic has a pass-band amplitude response nearly identical to the 6-pole Butterworth yet has much sharper roll-off characteristics making it a good choice for spectral analysis or for anti-aliasing applications. For the time domain, the PULSE mode low-pass filter has excellent transient response and phase linearity required for time domain applications such as transient (shock) measurements and time-domain waveform analysis.

For high-pass filting the 28612-HP6F provides a 6-pole, 6-zero high-pass filter with maximally flat pass-band.

The 28612 2-Channel 3 MHz Filter/Amplifier is a member of the Precision 28000 family of signal conditioners.

The 28000 Signal Conditioning System

Learn more about the 28000 Signal Conditioning System >

  • PFI's 8-Channel 200 kHz Filter/Amplifiers Cards

    The 28612 2-Channel 3 MHz Filter/Amplifier Card

    PRECISION 28612

    • High Frequency Anti-aliasing Filters
    • General Purpose Voltage Amplifier for Dynamic Measurements
    • Improve Signal-to-Noise Ratio for Resonant Transducers
    • High Frequency Band-Pass Filters
    • Low Drift DC Amplifier for Low-level DC Signals

28612 2-Channel 3 MHz Programmable Filter/Amplifier Features:

  • Two channels per card, 32 channels per chassis
  • Programmable single-ended/differential input
  • Programmable AC/DC input coupling
  • Programmable input termination (50 Ohms or Hi-Z)
  • Programmable gain: x1, 2, 5, 10, 20, 50, 100, 200, 500, 1000
  • Six-pole low-pass filter with programmable pulse/flat characteristic (model 28612-LP6FP)
  • Six-pole high-pass filter with maximally flat elliptic characteristics (model 28612-HP6F)
  • Cutoff frequencies programmable from 5 kHz to 3.15 MHz
  • Precise digital calibration

View the 28612 Programmable Filter/Amplifier Specification Sheet >

Voltage Filter/Amplifier Comparison Chart






AC/DC Voltage

AC/DC Voltage

AC/DC Voltage

Channels/ Card




Applicable Transducer

Low-Level AC or DC amps and LP, HP or BP filtering

Low-Level AC or DC amps and LP, HP or BP filtering

Low-Level AC or DC amps and LP, HP or BP filtering


2-wire with shield

2-wire with shield

2-wire with shield


500 kHz

190 kHz

3.15 kHz


x1/16 to x8192 with 0.05% Resolution

x1/16 to x1024 with 0.05% Resolution

x1 to x1000


4, 8-poles; FLAT/PULSE
Low-Pass or BP

4-poles; FLAT/PULSE

6-poles; FLAT/PULSE
Low-Pass or High-Pass

Cutoff Frequencies

2 Hz to 204.6 kHz

1 Hz to 102.3 kHz

FX02: 300, 1k, 3k, 10k, 30 kHz*

5 kHz to 315 kHz in 5 kHz steps
350 kHz to 3.15 MHz in 50 kHz steps


Single ended with Ground Sense

Single ended with Ground Sense


* Custom cutoff frequencies are available. Please consult factory.