quote author=Mike Walker link=topic=59531.msg417911#msg417911 date=1168101
somehow a radio isn't "pure" if there is a cpu inside. Whether the received mode is analog or digital, "computer processing" is the future.
Software-defined radios simply offer so many advantages. Look at how easy it was to "toss-in" a feature that before everyone thought was too expensive for the small benefit it seemed to offer...AM Stereo.
Check out the software defined radios from companies like Ten Tec (Tennessee Technology) at Universal Radio
http://www.universal-radio.com/catalog/commrxvr/0321.html
Sick of having only wide and narrow bandwidth? A software defined radio can give you 10, 20, 50 bandwidth choices. How many do you want? Want to adopt a new standard like HD, or DRM? No need to replace your radio...just bop in some new software (firmware, actually). AGC too slow, or fast? Improve it at any time, in the field. Sync-detector not losing it's lock during deep fades? FIX IT IN SOFTWARE. Your radio becomes infinitely upgradable. Now THAT is value for the money. And this technology will become cheaper, and cheaper. It's already in the Accurian HD radio from Radio Shack, which many of us picked up for a hundred bucks (after rebate).
No matter which side of the HD fence you're on, CPUs are our friends! They are certainly the future!
Was anyone here at the NAB Radio Show in New Orleans in '95? There was a demo of an "AMAX" AM Stereo tuner which used digital signal processing to eliminate noise and interference from things like computer monitors, flourescent lights, dimmers, etc. It was PHENOMENAL. And of course, no commercial product ever came of it. DSP COULD greatly improve analog reception in consumer products!
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Regarding a CPU in a radio, they always are (so far) inadequately filtered. Square waves have no business within 3 ft of a radio.
They are barely civilized enough to deal with audio.
I have two radios with continuously variable IF and a Collins 390 with steps from 100hz to 16 kkc.
Good radios are nice, but like fine musical instruments, the good ones cost money, and purists do prefer the real thing still over
digital convenience and cheapness. Because music and the human voice as an instrument were so familiar to those at the time radio was
born, as so many more people played then, it is natural the development of radio led to hi-fi ends.
I have used many types of radios, built several including a complex portable 3-band tube regenerative IF supehet of my own design ,
and can easily add any such "hacks" into real radios.
I have almost always found the older radios to tend more toward being purer in result, after a tune up, and "hot rodding the detector and AF system" up to speakers for hi-fi. Almost all the newer radios sound "squashed flat" to me, wish I could better define it.
There are certainly some transistor and IC-design radios I have that sound good, it's just a trend that newer stuff just ain't musical.
Software defined radios, like so many other economic "that's good enough" expendiencies, are the marketer's success stories in getting
people to accept something that is much cheaper to produce, and "almost as good".
My rental car in Houston this week was incapable of hearing any weak AMs over the 30db of noise from all the the digital noise from car controls, and I 've had many a rental where the radio display clock noise was all over the dial making squeals.
All that said, bring back AMAX standards. All for the good, and DSP in the audio chain is what should have been implemented on AM.
I accept and welcome the real improvement that can be made at detection, and the audio.
It should be possible to keep digital noise from an audio module out of the RF, if they care to use some METAL around the CPU, and
fillter the power to it like it needs to be.
Of course, there needs to be but ONE simple KNOB to regulate this, not a bizarre interface screen.
The small time loss here is acceptable, and such a system could be selectable on/off.
I really enjoyed the little bit of CQUAM I heard in the 90's, and hope it rebounds.
I never, ever found an AM stereo receiver available to buy on shelf, anywhere.
Or,as I wanted, an after detector adapter with stereo amp for your existing AM tuner.
As a luddite, I am way-slow to accept newfangledness as result of my employment fixing such fripperies.
And I chose old fashioned problems for myself whenever possible, as I trust the laws of physics far more than any
software and cpu solution to engineering.