Oscilloscope Measurement Bandwidth Expansion Using Frequency Response Compensation

Abstract

The bandwidth of a broadband sampling oscilloscope is a crucial performance indicator, as a result of which expanding its measurement bandwidth without altering the oscilloscope hardware has attracted considerable research attention. This study extended the oscilloscope bandwidth by compensating the oscilloscope’s frequency response. First, the theoretical relationship between the oscilloscope’s bandwidth, rise time, and their interdependencies were analyzed. Next, a scheme was designed to acquire the oscilloscope’s frequency response and compensate it in the distortion-free transmission direction. Experimental validation conducted using the Agilent 86100C oscilloscope with the 86117A sampling module demonstrated that the bandwidth extended by 15.2 GHz after frequency response compensation, and the rise time reduced by 2.5 ps. These results confirmed the effectiveness of the proposed approach. Finally, the oscilloscope’s frequency response was compared with varying degrees of compensation and the effect of this modification on the measurement of the same signal was investigated, concluded that there is a better effect when approaching complete compensation.

Keywords

• Bandwidth and rise time
• bandwidth expansion
• compensation frequency response
• oscilloscope