The Dytran Instruments model 4139 is a signal conditioner designed specifically for airborne flight testing. mModel 4139 is a six–channel signal conditioner designed to power up to six IEPE constant current type accelerometers while adding filtering, output biasing, and output limiting to present signal overdriving. The 4139 is intended for flight test use and operates from +28 VDC aircraft power. This miniature package measures 6.25 x 4.00 x 1.03 inches and weighs around .73 pounds.

The input power, output signals, and power to the accelerometers are interfaced by one D–subminiature multi–pin connector. The accelerometers are connected to the 4139 through six 10–32 jacks. A nominal +2.50 VDC offset is provided at the output. This allows for direct connection of the output signals to telemetry transmitter modulators which are designed to receive input signals over the range of 0 to +5 V. The output signal positive swing is limited to +5.6 V to avoid the possibility of overdriving the signal from one channel into the range of the adjacent channel. The 4139 has four mounting holes at the corners to accept #10 mounting screws for easy installation to the airframe.