It's news to me that SAWs are processors. I would be more inclined to
believe that a SAW filter may be used in front of some type of dsp
processor.
Last time I read about Surface Acoustic Wave devices they were basically
bandpass filters, that work similarly to Collins mechanical filters. The
electrical signal is converted into a mechanical signal using some type
of elecromechnical transducer (like a piezoelectric device, or a moving
coil device) and then propagated through some mechanically resonant
parts, later to be converted back to an electrical signal by another
electromechanical transducer. In the case of Collins mechanical filters
the signal travels as torsion in a rod, which has resonant disks
attached. In a SAW the signal travels as, you guessed it, a surface
acoustic wave, and the surface it travels across has some resonant
pieces either etched out or deposited upon it.
I've probably got some of the details, or maybe even the whole concept,
wrong. I'd love to hear about it from someone who has a better, more
authoritative explanation of either mechanical filters or SAWs. Is a SAW
a processor? Or is it just another way to make a bandpass filter?
DE N6KB
In the military applications for example, SAW processors (Surface
Acoustic Wave) handle this nicely, as do various hard wired ASICS. The
latter are comparatively cheap. Neither do much actual processing, as the
algorithm is pretty much hard wired in.
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