PC or not to PC September 9th, 2013
I have had a few emails about SDR and seen some recent postings, all of which centre around whether PC controlled SDR processing should be done inside the PC, (as it always has been) or shifted into the radio itself. The only reason for doing the latter is if the data flow from PC to radio cannot be made fast enough or there is not sufficient capacity to handle the large flow of data. Of course radios like the Elecraft KX3, although SDR, are self contained whilst retaining the option to shift the processing into a PC because of an
I/Q output. Best of both worlds really.
Whilst, there is nothing fundamentally wrong in shifting the processing into the radio, the undisputed fact is that there are some significant problems. I have already mentioned that updating the CPU in the radio is problematical at best, and probably impossible in practice. Only the likes of Apple and Microsoft have the ability to keep pace with CPU developments. With the CPU in the radio it could mean purchasing a new radio every few years to keep up with technology. And the cost of developing the operational software is very significant and time consuming. Something that a small manufacturer would not want to take on unless there were very well established rewards and they had the resources and finance. And so the big question is, can this move really be a wise one? Its ability to work is not the question, it is rather the cost of keeping up to date with CPU development. So let’s reconsider the established and proven option of letting the PC do the work.
If there is a question mark over the data flow ability, one has to ask why the music industry can handle so much data fast enough, using USB2 and Ethernet. Here, the data flow is enormous and speed is paramount. Yet there are very few examples of CPU being moved to the hardware. And this data flow is being handled satisfactorily on very modest computers. I am not talking about iTunes and the like, I am referring to professional music production and hardware modeling.
So let’s come back to what I have at the moment. An SDR system that uses the PC for all the hard work. I can easily operate at 30WPM CW and use noise reduction etc via Ethernet. I can do all the data handling I need and open multiple receivers. In fact there is nothing much I can’t do! My current laptop PC cost me less than £400. In three year’s time I could probably sell it for £100 and it would cost perhaps another £300 to £400 for me to upgrade to a new CPU. Perhaps the question I should be asking myself is, how much would it cost me to upgrade to a new radio in a couple of years or so? That for most if us will be the deciding factor. Peter G3OJV.