A sensitive instrument for measuring and recording the amplitude ratio of two video pulses from an ultrasonic echo train is described. The instrument has been designed primarily for ultrasonic attenuation studies using pulse‐echo techniques but may also be used for through transmission, and/or single echo measurements. The unit selects two pulses from the echo train, peak detects them, and measures their amplitude difference in a differential logarithmic voltmeter calibrated in decibels. The resultant output may also be applied to an external recorder. Provisions for zero suppression are included to permit the use of the most sensitive meter range (0.01‐dB resolution) when small changes in attenuation are to be measured against a large background attenuation. Automatic gain control, operating from the first selected echo, has been incorporated in order to maintain operation in the linear portion of the receiver dynamic range.