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SIM965 Bessel and Butterworth Filter

SIM965 Bessel and Butterworth Filter
  • Bessel and Butterworth filter types
  • 1 Hz to 500 kHz
  • 3-digit cutoff frequency resolution
  • High-pass or low-pass operation
  • Selectable rolloff
  • Continuous time (not sampled)

The SIM965 Analog Filter is ideal for signal conditioning applications where Bessel or Butterworth filters are needed. Bessel filters offer clean step response (negligible overshoot) and linear phase response, while Butterworth filters provide excellent pass-band flatness with some overshoot. A choice of high-pass or low-pass filtering is selected from the front panel.

SIM965 specifications

Cutoff frequencies are set with 3-digit resolution, and a choice of 12, 24, 36 or 48 dB/octave rolloff is provided for either filter type.

The SIM965 accepts input signals between ±5 V, and has unity gain. Its low noise and low harmonic distortion, along with a bandwidth of greater than 1 MHz, make it ideal in sensitive analog applications. If signal amplification is needed, the SIM910 JFET Preamplifier, or the SIM911 BJT Preamplifier should be considered.

Up to eight SIM965 modules can be housed in one SIM900 mainframe. Mainframes can be cascaded, allowing an unlimited number of filter channels for complex applications.

The SIM965 is also fully programmable. All functions can be controlled from a computer via the SIM900 Mainframe. Both RS-232 and GPIB interfaces are supported by the mainframe.

The digital control circuitry in the SIM965 is designed with a special clock-stopping architecture in which the microcontroller is turned on only when settings are being changed. This guarantees that no digital noise can contaminate low-level analog signals.

Specifications

Input  
Impedance 1 MΩ
Coupling AC or DC
Gain 1×
Max. input ±5 V
   
Filter  
Filter Low-pass or high-pass
Tuneable freq. range 1 Hz to 500 kHz
 
Resolution 3-digit
Type Butterworth, Bessel
Rolloff 12 dB/oct., 24 dB/oct., 36 dB/oct., or 48 dB/oct.
   
Output  
Noise <200 µVrms (1 MHz bandwidth)
THD 0.01 % (80 dB) at 1 kHz
   
General  
Operating temperature 0 °C to 40 °C, non-condensing
 
Interface Serial via SIM interface
Connectors
 		 BNC (2 front, 1 rear)
DB15 (male) SIM interface
Power
 		 Power supplied by the SIM900 Mainframe, or optionally by a user-supplied DC power supply (±15 V and +5 V)
Dimensions 1.5" × 3.6" × 7.0" (WHL)
Weight 1.5 lbs
Warranty One year parts and labor on defects in materials and workmanship