BF-48DGX
Low pass Bessel Filter with gain 

LPBF-01GX
Low pass Bessel Filter with gain

DPA 2FX/FS
Single-Pole Filter

The BF-48DGX differential amplifier / filter is designed to amplify and filter small bio-electrical signals. The input voltage range is ±12 V, the inputs are protected up to ±40 V. Two overload-LEDs indicate if the linear region of the amplifier is exceeded. All inputs and the output are BNC-connectors.

The INPUT impedance is 1 MOhm (other impedances are available on request). Using the differential INPUT configuration common mode signals and noise are removed allowing processing of signals with small amplitudes. The INPUT stage is followed by the offset compensation.

The one-pole Bessel HIGHPASS FILTER (option) has 11 corner frequencies (0.3 Hz - 10 kHz) and can be bypassed. The eight-pole Bessel LOWPASS FILTER has 12 corner frequencies (30 Hz - 20 kHz). The filter can also be bypassed. Optionally, a NOTCH filter can be used to eliminate 50 / 60 Hz noise. The NOTCH filter can be bypassed with a toggle switch. Filters and gain are monitored at BNC connectors (1V / step).

Specification

The LPBF-01GX amplifier / filter is designed to amplify and filter small bio-electrical signals. The input voltage range is ±12 V. All inputs and the output are BNC-connectors.

The unit is equipped with an unipolar input stage with an AC/O/DC switch. The input stage is followed by the offset compensation. The gain stage allows the amplification of the signal from 1-100 in 7 steps set by a rotary switch.
The amplified signal is applied to the output filter. This four-pole Bessel lowpass filter has sixteen corner frequencies (20 Hz - 20 kHz). An eight-pole filter is available on request. The
output filter can also be bypassed by using a toggle switch. Filter and gain are monitored at BNC connectors (1V / step).

Specification

The DPA 2FX differential amplifier / filter is designed to amplify and filter small bio-electrical signals. The input voltage range is ±12 V, the inputs are protected up to ±15 V. Two overload-LEDs indicate if the linear region of the amplifier is exceeded. All inputs and the output are BNC-connectors.

The INPUT impedance is 10 MOhms. Thus, the module can be used for direct recording of bioelectric signals, e.g. from peripheral nerves. Using the differential INPUT configuration common mode signals and noise are removed allowing processing of signals with small amplitudes. The INPUT stage is followed by the offset compensation operated with two controls (10-turn potentiometer and ±0.1 V, ±1 V, ±10 V toggle switch).
The GAIN range is x1 to x10000 and can be set with two switches (1-2-5-10-20-50-100 rotary switch and 1-10-100 toggle switch). The output signal is passed through the high- and lowpass filter.
The DPA filter module is also available as DPA 2FS with different filter specifications. 

Specifications

DI-01N 
Differentiator/Integrator Module

INR-01-T
Envelope/Integrator Module

WD-01
Windows Diskriminator Module

The DI-01N unit is designed for differentiating or integrating time dependent signals.

A low pass filter system with Bessel characteristic is integrated to realize a distortion free differentiation of very slow signals. Four time constants are available, set with a potentiometer. The selected time constant can be tuned between 0 and 100%.
In differentiator mode a variable damp factor can be activated (damp potentiometer) in order to avoid instability.
Output signals with DC offset can be adjusted with trim pots. A reset switch and a reset input are implemented to reset the system if necessary.

Specification

The INR-01-T envelope / integrator module is designed for generating envelopes from noisy INPUT signals, e.g. to facilitate detection of oscillations from extracellular measurements in excitable tissues. The INPUT signal is rectified by an “absolute value” circuit and subsequently applied to a “leaky integrator” for filtering. The time constant of integration can be set using a 6-position switch. Additionally, a THRESHOLD can be set in order to mask the noise around the baseline that contains no information of interest, and the OUTPUT envelope can be corrected for OFFSETs before amplification.

Specification

The WD-01 unit is designed for detection and recording of specific voltage level pulses in a noisy background.
This is achieved by producing a pulse when the signal's peak is within the lower and upper window levels. The window levels are controlled by ten turn potentiometers and can be adjusted to ±10 V.
Gain selection of x1, x10 , x100, pre-selection for polarity of the peak detection and independent selection of the polarity for lower level and upper level signals are features for very flexible use in several applications.

Specification