The design of signal generators for the measurement of receiver noise factor at 10- and 3-cm wavelengths

The design of signal generators for the measurement of receiver noise factors at 10- and 3-cm wavelengths is described, one of the main points being the elimination of connectors which give unreproducible results. To achieve this, the monitor and attenuator are made integral parts of the signal generator; the signal emerges through a length of Pyrotenax cable of over 10 db attenuation, giving a resistive output. The signal generator is calibrated by measurement of the power output when the piston attenuator is set to low attenuation but still obeys the theoretical law. Known power outputs of the order of 10−14W may thus be obtained with an accuracy of ± 1 db. The screening is such that no leakage can be detected with the most sensitive receivers.