IBAC System to be Discussed at IEEE Broadcast Symposium

Several sessions at the upcoming IEEE broadcast meeting in Washington look interesting. Some IBOC observers believe a new digital FM concept to be described by a German engineer “holds out the promise for a digital format that would eliminate some of the transmitter site implementation costs connected with IBOC,” said one U.S. engineer to RW Online.
In the paper titled, “A New DAB Scheme for the FM Band Based on Continuous Phase Modulation,” by Claus Kupferschmidt of Hanover University, Germany, he proposes a new broadcasting scheme for the transmission of digital audio signals simultaneously with existing analog FM radio (88-108 MHz) in adjacent channels, denoted as an in-band-adjacent-channel system. As described in the abstract, “This scheme enables the transmission of digital audio data in CD quality with a data rate of up to 200 kb/s within an FM 200 kHz channel. The digital transmission is based on continuous phase modulation and a proper reduced-state sequence estimator. CPM is the digital equivalent to analog FM and has a constant envelope, a great advantage, because existing nonlinear amplifiers can be reused to achieve good efficiency and low out-of-band radiation. CPM also enables broadcasting companies to reuse the existing infrastructure (amplifiers, antennas, frequency bands) to reduce investment costs and improve the chances for an introduction of CPM as a new broadcasting standard. We have conducted field tests in the city area of Hanover with a real broadcasting system based on the proposed CPM broadcasting scheme with the support of the northern German broadcast service in Hanover with encouraging results.”
The radio sessions at IEEE are on Thursday, Oct. 14. Other topics to be discussed include AM Digital Radio Mondiale tests in Spain and the latest about low bit rate codec tests and listener fatigue tests for the Tomorrow Radio project.
To register and see the program, go to: www.ieee.org/organizations/society/bt/symp/fullprogram.html