Laboratory test equipment for synchronous regenerative radiotelegraph systems

Traditional methods of testing radiotelegraph equipment, in terms of telegraph distortion, give results that are difficult to interpret operationally. In regenerative systems, however, the occurrence of errors in the printed copy is closely related to the element-error liability, and this fact has led to the development of error-counting test equipment in which signals passed through a system under test are compared with perfect signals direct from the signal source. The equipment covers a wide range of telegraph speeds, is easy to use and silent in operation, and it has proved to be a powerful tool in investigations of system behaviour and in development work. The suggestion is made that performance of regenerative systems ought in future to be specified in terms of element-error liability instead of telegraph distortion.