Omnia.9

[OKCRadioGuy]

Yes. The two big Os set the standard in service and support. Others aught to take some notes on how to do it right. The really nice thing about Frank's company is that he also offers many other products too. That gives me more opportunity to do business with them. So far I haven't been let down once.

 

[BobOnTheJob]

I could have simply emailed Frank Foti with this question, but feel it may be of interest to others, so here goes : With SSB, can the newly vacated 38-53khz spectrum be utilized for added data capacity using the DRE/FMeXTRA system? Will confusion result with something else occupying the spectrum where the receiver was designed to look for stereo information?

 

[FFoti1]

I could have simply emailed Frank Foti with this question, but feel it may be of interest to others, so here goes : With SSB, can the newly vacated 38-53khz spectrum be utilized for added data capacity using the DRE/FMeXTRA system? Will confusion result with something else occupying the spectrum where the receiver was designed to look for stereo information?

I believe a standard DSB decoder, in a receiver, would see any ancillary signal in the 38kHz - 53kHz spectra and try to decode it. Not sure what it would sound like...Probably not pretty.

Now, who knows, maybe there's some tech that could make use of a watermarked signal, embedded in the noise of this spectra?

-Frank Foti

 

[konbaasiang]

I've thought about this a bit. Using some kind of psychoacoustic masking, one could probably hide quite a bit of data in there without it being audible. However, this is only possible when there is stereo information -- if the audio was mono there would be nowhere for the data to hide.

So, one appropriate use for this data would be to add more bits to a digital version of the main audio channel in a hybrid digital radio system such as FMXtra (about which I know very little). As those extra bits would be most needed when there is wide stereo, this could work out nicely, as long as the system doesn't use diversity delay.

Otherwise, one could use it for a data service where transfer rate isn't critical.. You won't get many bits through during a mono newscast, but you should get plenty in a noisy rock track.

///Leif

 

[satech]

I've thought about this a bit. Using some kind of psychoacoustic masking, one could probably hide quite a bit of data in there without it being audible.

That sounds a lot like what Leonard Kahn claimed his "CAM-D" system for adding "digital enhancement" to analog AM would do -- the digital data stream was supposed to be masked by the analog modulation, so that there would be no digital noise audible on an analog receiver, unlike IBOC.

 

[Kmagrill]

As I recall, there were some technical limitations of the CAM-D system that kept it from being a contender. I vaguely remember that it was Kahn analog stereo up to a certain frequency (like around 8kHz), then mono digital for the upper frequencies. Since a lot of the stereo image is in the upper band, being summed to mono reduced the stereo imaging quite a bit. Also, the analog part remained subject to audible impulse noise, of course. Possibly, someone more familiar with the system knows if I remembered that correctly.

Anyway, acoustic masking is a perfectly valid method for masking all sorts of stuff, including CAM-D. If done properly in audio processing, it should be possible to chop the heck out of waves and still retain an open sound, however, I'll bet a distortion analyzer goes berserk when subjected to such a signal.