Tektronix dmm4050 and dmm4040 digital multimeters vfd 6 digit display tektronix dmm4040 the tektronix dmm4040 is a digital multimeter that has been designed for bench field service and system applicationsthis meter has a unique dual display enabling you to measure two different parameters of the same signal from one test connection to reveal signal quality issues like drift intermittent transients and stability you can view the data as a real time trend plot or a histogram with the