Pseudorandom noise loading for noise power ratio and law of addition

Layout, special features, and test results of a device for measuring pseudorandom noise loading are described. Intermodulation noise is estimated for many repeaters in tandem. The approach is useful in achieving reliable and accurate reproducible noise-loading measurements when the intermodulation noise is below the level of thermal noise, so that single-sideband repeaters can be tested in their normal operating power range. The multifrequency capability facilitates testing of parts or the whole of a heterodyne system. Correlation of intermodulation noise between different repeaters can be achieved by using a computer.