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XM Satellite Radio has applied for a patent to broadcast its signal into new HD Radios. Instead of XM using the FM band to receive signals in a car, using new HD Radio frequencies would allow the signal to be preserved as a higher-quality digital signal as it is intended, instead of in analog.

With the new technology, XM’s signal would be sent via an IBOC (in-band over carrier) digital audio broadcast. The patent also allows for MP3s, CDs and other audio options to be sent to HD Radios as well.

In the patent application, the company notes that its “high quality digital signal broadcast by XM Satellite Radio is ideally received by a digital satellite receiver for best audio reproduction, but in many instances an analog frequency modulation technique is utilized to reproduce the digital signal to take advantage of existing FM receiver car audio hardware.” The entire patent application can be read here as a PDF.

Source: http://www.fmqb.com/Article.asp?id=233540