IBOC proponents have been testing FM digital booster performance; now audio recordings of iBiquity Digital field tests are available.

NAB FASTROAD released test results in August. NAB’s Tech Check newsletter this week states that that three streaming video files containing audio recordings from the Boston-area field test portion of this program are on the FASTROAD Web page. iBiquity Field Test and Implementation Manager Russ Mundschenk was in charge of the lab and field testing for the booster technology and wrote the report.

These recordings offer an opportunity to experience how the digital booster impacts the received analog audio quality for three different scenarios as a test vehicle drives towards the booster site.

Since the digital-to-analog signal ratio will be increasing above the nominal –20 to –10 dBc value as the receiver gets closer to the booster, the quality of the received analog audio in this situation is of interest, according to NAB Tech Check.

In each case the booster signal is augmenting the hybrid HD Radio signal from the main transmitter of Greater Media-owned WKLB(FM), Boston. The first two scenarios used a digital-only booster’s effect on the main transmitter’s analog signal as received on a Chrysler and a Delphi receiver. The third scenario examines the effect of adding a low-power, synchronized, FM-modulated, analog carrier to the digital booster signal, to reduce the analog host interference caused by the digital carrier in the immediate vicinity of the booster. The recording for this third case was of analog audio as received on a Delphi receiver.

To access these video files, go to the FASTROAD projects Web page and scroll to the “Single Frequency Network Analysis” project.