Automated in situ testing of railroad telemetry radios

• US 6,216,095 B1
• Filed: 10/23/1998
• Issued: 04/10/2001
• Est. Priority Date: 10/23/1998
• Status: Expired due to Fees

• Current Assignee: Westinghouse Air Brake Technologies Corporation
• Original Assignee: Westinghouse Air Brake Technologies Corporation
• Inventors: Glista, Hans
• Primary Examiner(s): SHAH, KAMINI S
• Application Number:
  US09/177,383
• Time in Patent Office: 900 Days
• Field of Search: 246/187.A, 303/47, 340/825.69, 570/249, 570/252, 570/529, 375/225, 375/224, 702/117
• US Class Current: 702/117
• CPC Class Codes: H04B 17/16 Test equipment located at the transmitter
• CPC Class Codes: H04B 17/29 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. The transmitter performance is tested by measuring radio frequency (RF) carrier frequency, modulation frequency, deviation and RF output power. The test set is programmed to automatically measure these parameters, determine whether they meet minimum requirements, prompt the technician as to pass/fail status, and optionally display measured test data for use in radio repair, if required, or for statistical purposes.

Claims

1. A method of testing railroad telemetry radios comprising the steps of:

testing radio receiver sensitivity by bit error rate (BER) measurement using a BER modulator;

returning a pass or fail message depending on a predetermined criteria of BER detection;

testing transmitter performance by measuring parameters of radio frequency (RF) carrier frequency, modulation frequency, deviation and RF output power;

storing the measured parameters;

comparing the measured parameters with predetermined parameter limits; and

returning a pass or fail message depending on the results of the comparing step.

2. The method of testing railroad telemetry radios recited in claim 1 further comprising the step of generating measured data to either aid in radio repair or for data collection and analysis.

3. The method of testing of railroad telemetry radios recited in claim 1 wherein the step of testing the receiver comprises the steps of:

transmitting to the receiver a known low amplitude message comprised of a short pseudorandom pattern continuously repeated which is demodulated by the radio receiver; and

counting a number of errorless messages received over a specific period of time, the receiver sensitivity passing the test if the number of correct messages received is higher than a predetermined minimum value.

4. The method of testing railroad telemetry radios as recited in claim 3 wherein the radio tested is part of a Locomotive Control Unit installed in a railroad locomotive and the test is performed on the locomotive.

5. The method of testing railroad telemetry radios as recited in claim 3 wherein the radio tested is part of an End of Train (EOT) unit and the test is performed in the field without sending the EOT unit to another location.