Hackett's Cove, NS - Jun 15, 2011 - Nautel commissioned NPR Labs to study its HD PowerBoost with Asymmetrical Sideband technology so Nautel could obtain an independent analysis of the technology to both verify the system operates as anticipated and did not create any deleterious effects to either analog or HD Radio reception. Laboratory tests were conducted to measure the effectiveness of Nautel technologies under varying conditions. Noise and sensitivity were measured free of multipath and repeated with induced multipath and fast-fading. All tests included the addition of additive Gaussian white noise to simulate background RF noise from potential co-channel FM stations and/or environmental RF noise.
NPR Labs released the report on June 1, and according to Nautel, the report has validated the technology in improving reception coverage, power output and efficiency for HD Radio transmission. In the report, NPR Labs Senior Technologist John Kean stated "...in comparison with conventional IBOC operation, HD PowerBoost had little or no measurable impact on the performance of analog test receivers, even with the highest-tested asymmetrical digital sideband ratios of -10/-20dBc. Asymmetrical operation reduced the audio noise level of the home receivers by up to 3dB as either sideband was reduced." Kean also noted that mobile HD Radio receivers could operate well with asymmetrical transmission.
Following the Laboratory tests, WAMU in Washington performed on-air testing, which was the subject of a joint paper and presentation by Nautel, NPR and WAMU at the 2011 NAB Show. According to Nautel, real-world tests on WAMU further verified HD PowerBoost operation and followed extremely closely to the coverage prediction models for total dBc, which NPR Labs developed.