Migrating Balanced Measurements from 8903B to U8903A
アプリケーションノート
Abstract
Hewlett-Packard introduced the HP 8903B audio analyzer in 1980. It quickly became the industry standard because of its unprecedented performance and features. The U8903A audio analyzer is the next-generation audio analyzer from Keysight Technologies, Inc. (refer to Figure 1). This application note explains the HP 8903B and U8903A audio analyzers balanced connection architectures, and the accessories for migrating connections from the HP 8903B to U8903A.
HP 8903B Output and Input
Older generation instruments like the HP 8903B provided BNC connector pairs for both the generator output and the analyzer input. Figure 2 shows a simplified block diagram of the analyzer input.
The ‘HIGH’ BNC connector is used in isolation when an unbalanced measurement is made. When a balanced measurement is made both the ‘HIGH’ and ‘LOW’ BNC connectors are used. The center conductor of the ‘HIGH’ connector carries the signal and the ‘LOW’ conductor carries the inverted signal. The outer conductors of both connectors are connected to ground. The generator output connections function in a similar way