Abstract: A radio interference detection and screening system for performs on-locomotive testing of Locomotive Control Unit (LCU) radios. To eliminate bit errors during LCU sensitivity testing (also known as Bit Error Rate (BER) testing), the system detects interfering transmission signals which may cause bit errors in the transmission of test data, and suspends the LCU sensitivity performance testing during periods of detected external transmissions. Once the interfering transmissions are no longer detected by the system, the LCU then resumes the LCU sensitivity performance testing.

Abstract: Railroad telemetry radios are tested by an automated method for in situ testing, so that only those units requiring adjustment and maintenance are removed. A multi-function test set is programmed to automate testing of the radios used in a telemetry system in conjunction with other test software embedded in the host telemetry devices. The radios contain both a transmitter and a receiver. Both are individually tested to verify proper performance. Receiver sensitivity testing of the radio is tested by bit error rate (BER) measurement with test software and a dedicated BER modulator. A known low amplitude message comprised of a short pseudorandom pattern continuously repeated by the test set BER modulator is demodulated by the radio receiver. The test software processes the received data and counts the number of errorless messages received over a specific period of time. The receiver sensitivity is known to be acceptable if the number of correct messages received is higher than a predetermined minimum value.