The STI Audio Quality Test System is compatible with Field Test 7 software and A/D converter from National Instruments. The STI AQT System includes data acquisition hardware and software and a specialized audio sample analysis capability. The STI AQT is designed operate on a communication system by continuously transmitting a audio test signal generated by the STI AQT Generator while the mobile STI-9400 is used to acquire signal intensity and audio quality data during drive tests.
The STI AQT may also be combined with optional STI products to synchronize data acquisition with the an intermittent test requirements. Two topologies are available. First, by adding the optional STI PTT-Switch and GPS Timer, a mobile transmitter in the test vehicle can be used to synchronously transmit the AQT test signal up to the site for measurement at the site by an STI-9400 system with the AQT option. Secondly, a laptop running the STI GPS Timer application with the STI Parallel Port Switch and AQT Test Generator can be used at the transmission site to transmit a time synchronized test signal to the STI-9400 in the mobile vehicle. Measured data and location data can be combined in a single project after the test is complete.
The Audio Quality Test option combines the ability to measure RSSI voltage, converted to signal strength through a calibration table, with the ability to digitize a sample of audio signal and compute SINAD from the sample.
Either one or both of the two tones are broadcast from the site under test using the audio generator connected to the site audio input. The audio signal is sampled at 10,000 Hz rate for about eight tenths of a second producing over 8000 samples. This can be done with both wide and narrowband analog radios taking the guess-work out of Narrowband Migration.
12dB SINAD / scope view of audio sample
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