24 August 2011
Experimental authority granted by request
In a letter to the FCC, Omnia President and Founder Frank Foti has updated the organization on the progress of FM-Stereo Single Sideband Suppressed Carrier (SSBSC) field testing, and has confirmed that experimental authority requests have been granted by the FCC. This enables individual stations to immediately test and experience how SSBSC transmission might improve coverage and quality in their specific markets. A copy of this letter is available on the Omnia website at http://www.omniaaudio.com/downloads/white-papers/MPX-SSB-White-Paper.pdf. It can be included with a request for experimental authorization by a broadcaster.
This letter outlines a method, as an option to the present double sideband suppressed carrier (DSBSC) system, utilizing single sideband suppressed carrier (SSBSC) modulation of the stereophonic subcarrier in the FM multiplex baseband signal. A detailed description of this concept can be found in a white paper, authored by Foti, on the Omnia website at http://www.omniaaudio.com/downloads/white-papers/MPX-SSB-White-Paper.pdf
“The intended goal of this effort is to reduce perceived multipath of the FM channel through a reduction of occupied bandwidth and sideband pairs of the modulated carrier. There are multiple benefits for the broadcast signal, which I feel will be perceivable to the listener: A reduction in multipath induced distortion, additional protection to the spectrum used for RDS, SCA signals, and HD-Radio content - thereby improving data robustness in the receiver.” Says Foti, who continues:
“To date, I have tested the SSBSC method in our engineering lab and found it to be compatible with existing FM radio receivers. Likewise, the system does not exhibit any degradation to the FM modulated carrier, as peak modulation remains exactly the same, as well as the performance of stereo separation, and frequency response. If anything, the occupied bandwidth of the FM channel is reduced a bit due to the increased modulation index. This results from the SSBSC method utilizing only 38kHz of spectrum (20Hz – 38kHz) as compared to the 53kHz (20Hz – 53kHz) spectrum required with the DSBSC method. The National Radio Systems Committee has convened one of their sub-groups to look into the method further.”
Omnia Audio has implemented a SSBSC option for the stereo generator function employed in our Omnia.11 FM audio processor. Thus, activation of the technology is available for immediate implementation by Omnia.11 users with an easily obtainable experimental authorization from the FCC and a single touch of the SSBSC option, which appears on the front panel of the Omnia.11.
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