[aprssig] Dear Mr Kenwood (MicE decoding)

Scott Miller scott at opentrac.org
Mon Dec 28 21:17:01 EST 2009


I already dealt with it years ago, I was just making a point to Bob that 
lookup tables are almost a necessity for some of this stuff.  Just 
because it's one statement in QBASIC doesn't mean it's going to be easy 
on a low-cost MCU.

Scott
N1VG

Chuck Gooden wrote:
> Have you considered you may be using the wrong hardware then?  Your a 
> software guru...deal with it.
> 
> Scott Miller wrote:
>>> Done.  Plus a little cleanup here and there...  It was designed
>>> to be a pretty simple manipulation of bits.  A table was never
>>> intended.  That was just how Ian decided to represent the
>>> algorithm in the spec making it appear overly complex when in
>>> fact, it is a very simple offset of bits.
>>
>> And how would you suggest implementing the speed and altitude?  Where
>> speed = (1.08^x)-1 and altitude = 1.002^x?  Yeah, it's easy on a PC
>> where you've got floating point support and memory and CPU cycles to
>> burn.  Not fun on an 8-bit MCU that more often than not doesn't even
>> have a hardware multiplier.  Certainly not as simple as the single
>> QBASIC statement needed to handle it might imply.
>>
>> Scott
>> N1VG
>>
>>
>> _______________________________________________
>> aprssig mailing list
>> aprssig at tapr.org
>> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
>>
>>
> 
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
> 
> 





More information about the aprssig mailing list