higher audio quality of a single program allowed the full data stream. The FCC has declared "one free over-the-air digital stream [must be] of equal or greater quality than the station's existing analog signal". If the FCC disallows analog simulcasting, each station will have over 300 kbit/s bandwidth available, allowing for good stereo quality or even surround sound audio, together with multiple sub-channels, and to a lesser extent more freedom for low-power, personal FM transmitters, to pair modern smartphones, computers, and other devices to legacy analog FM receivers. The broadcasting industry is seeking FCC approval on future HD receiver models, for conditional access; that is, enabling the extra subchannels to be available only by paid subscription. NDS has made a deal with iBiquity to provide HD Radio with an encrypted content-delivery system called "RadioGuard". NDS claims that RadioGuard will "provide additional revenue-generating possibilities". Most all existing FM receivers tuned to a channel broadcasting a HD signal are prone to increased noise on the analog signal, called "HD Radio self-noise", due to analog demodulation of the digital signal(s). In some high fidelity FM receivers in quality playback systems, this noise can be audible and irritating. Most all existing FM receivers will require modifications to the internal filters or the addition of a post-detection filter to prevent degradation of the analog signal quality on stations broadcasting HD Radio. Reduced analog signal Radio stations are licensed in the United States to broadcast at a specific effective radiated power level. In 2008, NPR Labs did a study of predicted HD Radio operation if the digital power levels were increased to 10% of the maximum analog carrier power as is now allowed by the FCC under certain circumstances, and found the digital signal would increase RF interference on FM. However the boosted digital HD signal coverage would then exceed analog coverage, with 17% more population covered in vehicles but 17% less indoors. High costs The costs of installing the system, including fees, vary from station to station, according to the station's size and existing infrastructure. Typical costs are at least several tens of thousands of dollars at the outset plus per-channel annual fees (3% of the station's annual revenue) to be paid to Xperi for HD‑2 and HD‑3 (HD‑1 has no royalty charge). Large companies in larger media markets – such as iHeartRadio or Cumulus Broadcasting – can afford to implement the technology for their