Generating phase modulation.

On 12/16/2009 10:12 AM, Mark wrote:
> On Dec 15, 9:14 pm, Eric Jacobsen<eric.jacob...@ieee.org>  wrote:
>> On 12/15/2009 6:45 PM, Mark wrote:
>>
>>
>>
>>
>>
>>> snip
>>>> When it comes down to analog voice and the ability of a human to pick
>>>> out information in a noisy or weak signal, though, it becomes too
>>>> subjective to compare.  The brain does have a really good decoder for
>>>> human speech (usually), and that may help a link work in some places
>>>> where a digital system might lose lock.
>>>> But for transporting bits, I don't there's much contest.
>>> yes, I'm talking about transmitting voice info, not data.. over a
>>> dedicated public safety channel..
>>> If you were trapped in a burning building and your life depended on
>>> contacting  your backup 25 feet away, would you want a simple analog
>>> FM radio or a complex encrypted digital device?
>>> Mark
>> The answer would depend on a lot more than just that difference.   I'd
>> want the one that got the most reliable signal, and in many (but not
>> all) cases that's the digital device.   With proper engineering it's
>> pretty much nearly always the digital device.
>>
>>
> my point is that the Eb/No performace of the modulation is only a very
> small factor in the overall reliability of getting the message through
>
> I'd say the number of SMT solder joints in the hardware is a more
> important factor...
>
> Mark

There are tons of factors, obviously.  I've not personally seen solder 
reliability problems, or even part count, dominating hardware 
reliability for well-engineered systems for a long time.  Consumer cell 
phones have a pretty high degree of integration and seem to have pretty 
reliable electronic hardware on the whole.

Simpler is certainly more reliable in general, but manufacturing 
technology these days is capable of putting those factors in the noise 
for even highly integrated systems.  A bad part selection or a rogue 
vendor (e.g., bad caps) seems more likely, and that can happen to analog 
as well as digital systems.

-- 
Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com