[time-nuts] Software defined spectrum analyzer

[jimlux]

Magnus Danielson wrote:
> On 12/12/2010 02:31 AM, jimlux wrote:

> 
> Two VCOs covering 1-2.2 GHz could through mixing and selecting between 
> sum and difference output filters (i.e. lowpass and highpass) cover that 
> without too much difficulty. Except for the highest end, there is a 
> degree of freedom in setting the oscillators to their individual 
> frequency which naturally could be used to avoid "bad" frequencies to 
> leak into the IF for instance.
> 
> C


Yeah.. but there's a whole raft of inexpensive PLL chips with multiple 
VCOs on them to cover wide ranges (e.g. all cell, mobile data, and WLAN 
bands).. I'll bet they're using one of them.  If a chip exists with VCOs 
that does the job, that's going to be cheaper and easier than any sort 
of add/subtract/mix/divide scheme.


This is an example of a new class of lab instruments.. you pay for the 
hard part (the RF design and performance) and software takes care of the 
rest, and since software has almost zero reproduction cost....

For today, there's probably a significant "value added" in the software, 
so it might not be free... but over time, that will change.

And, if it works out nicely, standardized interfaces (like 50 ohms or 
resistor color codes) will evolve, so the same software will work with a 
$500 inexpensive widget or a $10,000 high performance widget from Agilent.

There will always be a market for software tailored to a specific 
market/need (like standards or regulatory compliance) that will cost, 
but for generic functions (like a power spectrum) that will probably be 
free, or close to it.

I wonder if there's an interface for this for my iPad?