VBF40  Multi-channel -  1 Hz - 255 kHz   + 70 dB Gain  5 built in filter responses
Top of range  Versatile filter / amplifier system

Filter cutoff range 1 Hz to 255 kHz Flexible Gain -20dB to + 70dB 5 built-in filter responses 2 lowpass, 2 highpass, and bandpass Sharp 135 dB / Octave filters Manual and computer control Easy to use 1-16 channels per rack Signal level indication Rack mounting Wide dynamic range   VBF 40 pdf data sheet (90 kB)
	Kemo VBF 40 Top range analogue filter

The Kemo VBF40 combines programmable amplification and high performance analogue filtering in a versatile easy-to-use package. Ideally suited to today's hard-working flexible data capture and analysis applications. The VBF 40 has a unique combination of input gain, 5 built in filter responses, and output gain. This combination makes the VBF 40 a flexible signal filtering and amplification unit with capabilities suited to a wide range of applications.
The VBF 40 is part of the Kemo VBF 40 series of filters, also available are the 2 channel, VBF 42 and the 4 channel VBF 44  with a range of channel coupling options for channel tracking and 'stereo' filtering.
Easy to use front panel controls, BNC input/output connectors, and a very versatile set of filter responses make the VBF 40 a top range laboratory filter.

Frequency Range 1Hz to 255kHz
The VBF40 channels can be independently set by the front panel to frequencies between 1Hz and 255kHz in four 255:1 ranges. 1Hz - 255Hz, 10Hz - 2 550Hz, 100Hz - 25.5kHz, and 1kHz - 255kHz.

Lowpass / Highpass
Each channel can be independently set to high or low pass, over the range 1 Hz to 255 kHz.

5 Filter Responses
Each channel has 5 filter responses, sharp lowpass, sharp highpass, time optimised lowpass, time optimised highpass, and a bandpass filter response.

Gain Range
The gain of each channel can be programmed between -20dB and + 70dB in 2dB steps (including the switchable 10dB input attenuator). Up to 40dB of gain is available before the filter, the rest is post-filter.
Input level LEDs are visible on the front panel.

Flexible Input
Input AC coupling may be selected if desired.
The inputs are differential, with a front panel switch to convert them to single-ended. Inputs and outputs are BNC, mounted on the front panel.


Summary Specification

Channels	1 - 16 per rack
Control	Manual LED and thumbwheel RS 232 or  GPIB
Frequency	1 Hz - 255 kHz (4 ranges)
Bandwidth	> 1 MHz,  1V signal, 0dB gain, highpass filter and filter bypass
Input Gain	0 dB to +40 dB, in 20 dB steps, with switchable -10 dB attenuator
Output Gain	-10dB to + 30 dB, in 2 db steps
Filters	5 Switchable; 2 Lowpass, 2 Highpass, and Bandpass
Filter Responses	L1, L2, H1, H2, B1
Input Coupling	AC / DC
Input Mode	Single ended or differential
Signal level	+/- 10V pk-pk (usually with 'headroom')
Signal Level Indication	LEDs on front panel
Size	3U 19"
Power	90 -120 / 180-240 Vac 50/60Hz

Applications
The versatility of the VBF 40 makes the application area very large. They include, classic anti-aliasing, random noise conditioning, all types of mechanical testing, audio work, medical signals, seismic and geological signals, SONAR and oceanographic, military and a wide range of others.

Response Versatility
Each VBF40 channel can be switched to five different filter responses to suit the application. 2  lowpass filter responses, 2 highpass filter responses and one bandpass filter for each channel.
The 5 filter characteristics are:
Flat to Fc  -80 dB at 1.5 Fc
Flat to 0.6 Fc -3 dB at Fc -96 dB at 4 Fc linear phase
Flat from Fc  -80 dB at 0.67 Fc
Flat from 1.67 Fc -3 dB at Fc -96 dB at 0.25 Fc
Flat at Fc -3 dB at 1.06, 0.9 Fc -35 dB at 1.5, 0.67 Fc
The filter may also be switched out completely.

Ease Of Use
The VBF40 has large, bright LED displays for all parameters and a simple user interface using pushbuttons for function selection and a rotary control for numeric entry. Non-volatile storage for 3 complete configurations is provided. 
Computer control is also available, with a choice of interfaces. 
One VBF40 frame can control a total of 64 channels if needed.

Block Diagram



 This shows the generic block diagram for a Kemo 40 series filter channel. The VBF 42 has additional features in the way the 2 channels can be connected together to make notch, bandpass, and bandstop filters.

Related Systems
The VBF 40 is part of a range of filters.
The VBF 42 is a 2 channel 1U 19" unit with series and parallel coupling of the channels to give bandpass, bandstop and notch filtering.
The VBF 44 is a 4 channel system, with channel grouping and tracking functions which make it ideal for twin sensor applications.

Price/Performance Ratio
Due to its versatility the VBF 40 range offers significant price performance advantages over similar filter systems.
Tremendous care has been taken to ensure repeatable and dependable performance.
  VBF 40 pdf data sheet (90 kB).