Abstract: A method and device for comparing two generic digital signals over a wide range of data rates and for counting the number of bit errors between digital signals under the conditions of noise and jamming. The bit error tester of the invention compares the digital signal sent with the digital signal received back from the unit under test and outputs the error signal. In the preferred arrangement of the invention, a field programmable gate array is used and a switch and LED display are used to introduce and monitor a time delay in the sent signal to ensure that the signals are in time alignment prior to comparison.