Looking at Real Time for Linux, PowerPC, and Cell (developerWorks) [LWN.net]

Looking at Real Time for Linux, PowerPC, and Cell (developerWorks)

Posted Aug 25, 2005 3:39 UTC (Thu) by dlang (✭ supporter ✭, #313)
In reply to: Looking at Real Time for Linux, PowerPC, and Cell (developerWorks) by mikec
Parent article: Looking at Real Time for Linux, PowerPC, and Cell (developerWorks)

a software radio has the huge advantage that it can receive multiple signals at the same time.

with hardware you have to have a physicly seperate receiver for each signal you want to receive.

there are a lot of situations where you have a lot of radios in one place to try and monitor lots of signals (and a scanner doesn't do the job, it hops between channels with one receiver, it still only listens to one signal at a time)

in addition, software radios can handle new types of signal encoding with just software changes, including spread spectrum sideband, etc that would require hardware redesigns for traditional equipment.

and finally, there are some things that just can't be done reasonably in hardware that software makes possible. The advances in telecom speeds are mostly due to the audio-speed circuits being changed from being implemented in hardware to being software, the software has made it possible to adapt the signal to the lines (and detect the inteded signal from the lines) to a degree that was considered physicly impossible not too long ago, and these changes have made much of the broadband service that people use possible. we really don't know what will end up happening as this scales up to higher frequencies, but past experiance makes it clear that it will be things that we can't imagine today.

and before you say that hardware radios give you more flexibility, consider that you can't purchase a scanner in the US to receive some frequencies becouse the hardware to do so has been outlawed (cellular freqs for example). even excluding these limits, you are in just as much need to hack the hardware as you would be the software of a software controlled radio if the manufacturer decides to put limits in there.

besides the origional article just listed that as one of the things that could be done if performance was to improve that much, not that that was the only reason to improve performance to that level.

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