FMeXtra is a deprecated in-band on-channel digital radio broadcasting technology created by Digital Radio Express. It is intended to allow a second all-digital signal to be broadcast in simulcast fashion with an existing analog FM radio station, offering a less noisy signal that was particularly useful in urban environments where multipath distortion can seriously degrade analog FM transmissions. It can also support a second all-digital channel within the same frequency, allowing two channels to be broadcast by a single FM station. FMeXtra was one of two competing systems considered by the FCC for standardization in the U.S., and by extension, Canada and Mexico. The other system, HD Radio, could carry up to four signals in a single channel and offer higher quality audio. FMeXtra's appeal was that it could be implemented for relatively low cost, adding only a single rack mount case to a radio station's existing equipment and transmitter plant. It also had no licensing requirements, unlike HD Radio which allows one free channel but requires 3% annual royalties for additional channels. After extensive consultations, the FCC chose HD Radio over FMeXtra. FMeXtra continued for a time before rebranding itself VuCast as a datacasting play, but this saw little use and Digital Radio Express eventually went out of business. References to the system generally end around 2013. Description The system is run from a single rack unit box called the X1 Encoder, which is actually based upon a personal computer server and digital audio hardware from Lynx Studio Technologies (LST). Control is entirely via software, via gigabit Ethernet, USB, serial port, and SVGA video monitor. All processing is handled internally by a Pentium 4 running Windows XP. FMeXtra is fully compatible with HD Radio, which uses additional radio spectrum beyond the ±100 kHz signal. It is not compatible with all existing subcarriers. Thus, a radio station might have to remove its radio reading service for the blind, and replace it (and its dependent listeners' receivers) with a digital one. This would take up much less bandwidth, particularly since voice can be highly compressed. The signal is partitioned so that RBDS, stereo, or other existing subcarriers can be protected, at the expense of bandwidth. If used only for monophonic transmissions, no RDS protection exists for stations in Europe. The codecs used are AAC and aacPlus v1 and v2 and sample rates of 8 kHz (telephone quality) to 96 kHz (surround