The minimum operational performance characteristics specified herein are designed to ensure that aircraft equipment certificated to them will be compatible with the ICAO ILS Standards and Recommended Practices. In certain cases (notably signal input ranges) a margin of performance which engineering experience has shown to be desirable has been provided over the threshold values necessary for system compatibility. Note that this document assumes that the antenna, cable and associated connectors introduce 0 dB loss to signals arriving at the receiver. Additionally, environmental test requirements have been specified in respect of the electrical parameters which experience has shown to be susceptible to the effects of environment.