Dynamic range extension apparatus and method

• Main Authors: Bourde, Christian A, Taylor, J. Barry
• Format: Patent
• Language: English
• Published: 20.05.2003

The invention relates to measurement systems. In particular, the invention relates to extending the dynamic range of lower power signal measurements in the presence of higher power signals. An apparatus, method and system extend the dynamic range measurements performed on a device under test. The apparatus and method compensate for the non-ideal characteristics of the measurement system elements. Further, the apparatus, method and system facilitate low-level distortion measurements and improve the accuracy of such measurements using a novel cancellation signal approach. The dynamic range extension apparatus has an input port for accepting an input test signal from a signal source and an output port for delivering an output signal to a measurement processor. The apparatus comprises a signal splitter at its input, a cancellation pathway, a test pathway and a signal combiner at its output. The system comprises a signal source that provides an input signal to the input of the apparatus and a measurement processor at the output of the apparatus. In the dynamic range extension apparatus, method and system, a signal from the input signal source is split by the signal splitter into two signals. A first split signal passes through the cancellation path where it is phase shifted to produce a cancellation signal. A second split signal passes through the test path where it is applied to the device under test to produce a response signal that is attenuated. At the outputs of the cancellation path and the test path, respectively, the cancellation signal and the attenuated response signal are combined by the signal combiner prior to being delivered to the measurement processor. The measurement processor accepts the output signal from the apparatus and measures the low-level distortion signals within the output signal.