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 Combustion Sensors


RM 4VF3 1 

  • 500 Hz – 127,500 Hz variable filter
  • Selected for combustion pressure sensors
  • Evolved proven design, many in world-wide use
  • Settable gains, input configuration and filter frequency



The Kemo RM-4VF3 and RM-8VF3 are a range of filters designed to aid automotive combustion Engineers.  The RM-4VF3 reduces the effects of in cylinder resonance of pressure sensors during the power cycle. The units were originally designed with close collaboration from automotive engineers across several international sites. The filter type (Kemo Response 37) and hardware configuration were specifically chosen to suit both the signal analysis path, and existing systems hardware. This is the third generation version of this unit. Earlier versions have been in near continuous use for many years.


The Kemo RM-4VF3 and RM-8VF3 are mains powered with all connectors on the rear panel - signal connectors are BNC. The filter frequency setting, IEPE transducer supply, signal input configuration and gain are all internally set by color-coded jumpers - under the screw down top cover. The filter may be set from 500 Hz to 127,500 Hz in 255 steps of 500Hz.

Filter Response 37 is a flat to cut off,
reduced phase delay filter selected for
its suitability for combustion pressure
sensing application. It was trialled before
selection and compared to other filter
responses. The filters in the RM-4VF
series exhibit close phase and
amplitude matching.




 World Leader In Filtering Presents The Newest in Combustion Filtering




RM 4VF3 


Channels:-        RM-4VF3 = 4 channels            RM-8VF3 = 8 channels

Filter Frequency:-    500 Hz – 127,500 Hz, in 255 steps of 500 Hz

Filter Type:-        Kemo Response 37 – data sheet on response at web site or upon request

Filter matching:-        +/- 0.025dB amplitude, +/- 1o phase, between channels (typical)


Input type:-        BNC connectors

Input Impedance:-    100 kΩ    

Input configuration:-    Single ended or differential, set by jumpers

Input Coupling:-        DC or AC coupling, IEPE +24V DC 4mA, all set by jumpers

Input Gain:-        x1, x2, x5, x10, x100 (giving 1,2,5 steps to x1000) set by jumpers

Signal amplitude:-    +/- 10V pk-pk ( typically plus ‘headroom’)


Output Type:-        BNC Connectors

Output configuration:-    Single ended

Output Impedance:-    50 Ω

Output Offset:-        < +/- 2.5 mV    


Power:-            110/230 V,  50/60 Hz AC, typically 20VA   



Dimensions:-        Basic 1U, 19” 270mm (10.6”) deep.

            44 x 435 x 270 mm (0.75 x 17.3 x 10.6”) excluding handles and mounting ‘ears’

Weight:-        3 kg (7lbs)