Built In Test (BIT) Capability

The concept is not new as some military transceivers currently make these tests at power up, periodically during transceiver operation and manually upon operator command.

The FlexRadio SDRs contain both a broadband exciter and one or two broadband receivers.  Thus I maintain that if this capability does not presently exist, it could be quickly be implemented and become an invaluable tool to both monitor and maintain the radio’s performance.

The basic concept would be to generate a test signal with the Exciter, pass it out the XCVR port and back into the antenna port with a coaxial jumper, through the full receiver chain to the SCU.

The first receiver frequency sweep would bypass the ATU, preamp and filter bank to create a base line.  If this produced an expected signal level over the swept frequency range, continue to the next test else declare a fault.  Provide an option to save the results.

Increase the signal level and make another sweep.  Repeat N times to check the ADC's dynamic range and the SCU.  If this produced the expected signal levels over the swept frequency range, continue to the next test else declare a fault.  Provide an option to save the results.

Next, with a high signal level, exercise all the path switches, one at a time, to confirm their low insertion loss and high open circuit isolation.  If acceptable, pass else declare a fault.  Provide an option to save the results.

Next, with a high signal level, sweep the ham band filters, one at a time, showing insertion loss, band shape and stop band characteristics.  If acceptable, pass else declare a fault.  Provide an option to save the results.

Next, with a low signal level, check the preamp gains over frequency.  If acceptable, pass else declare a fault.  Provide an option to save the results.

Repeat the above for the second SCU, if present.

Other tests could be generated to test the transmitter parameters using a dummy load.

The benefit to the customer is a quick, simple hardware validation, and fault detection of subtle failures.

The benefit to FlexRadio is to showcase their SDR capability, assure customers of product performance, early detection of trends and improve product capability.