The VectorStar MS4640A-Series Vector Network Analyzer (VNA) System measures the magnitude and phase characteristics of networks, amplifiers, attenuators, and antennas. It compares the incident signal that leaves the analyzer with either the signal that is transmitted through the test device or the signal that is reflected from its input. Figure: Transmission Measurements and Figure: Reflection Measurements illustrate the types of measurements that the MS4640A-Series VNA can make.