SDR-14 vs SDR-IQ

[Mike O'Dell]

i believe the OMAP processor datapump can take data off
fast A/Ds with little or no assistance at all. that's what
it does in cellphones. I'm also surprised nobody is using
the SHARC processors from ADI. they form the heart of most
cellular base stations these days, and they interface
quite cleanly with the ADI A/D and D/A products (no surprise
there). given that the SHARC is routinely programmed in C,
i'm surprised nobody has looked at exploiting that.

hmmmm.... lots to ponder

	-mo


On 1/17/10 8:55 PM, Frank Gentges wrote:
> Those of us with the SDR-IQ can look at a second unit with the same or
> better A/D and a bank of very fast (15 nsec) static memory that can
> capture a full frame of data and then download it via USB, PCI or other
> fast transfer to a PC or FPGA to generate a full width spectrum. A very
> simple and cheap board if we can only master the verilog for the FPGA.
>
> You can harvest those cache rams out of your old 486 computers for the
> fast static rams. (Hey kids, its dumpster diving time.)
>
> In the end we have separate SDRs.
>
> Now back to our verilog class.
>
> Frank K0BRA
>
> Mike O'Dell wrote:
>> sounds like it's time to get the ADI application notes
>> and build an add-on board for the OMAP Linux machine.
>>
>> -mo
>>
>>
>> On 1/17/10 5:26 PM, wb4jfi wrote:
>>> wb4jfi wrote:
>>>> Mike O'Dell wrote:
>>>>> I'm trying to reconcile why the SDR-IQ is so much cheaper
>>>>> than the SDR-14
>>>>>
>>>>> the high-performance ADI parts in both of them are identical -
>>>>> the A/D and the digital downconverter
>>>>>
>>>>> the data delivered across the USB2.0 interface is essentially
>>>>> identical
>>>>>
>>>>> the -IQ has *more* filters and switching
>>>>> the -IQ has *more* computes and digital hardware
>>>>>
>>>>> as a result it's hard to understand how the BOM cost of the -IQ
>>>>> is really any less than the BOM cost of the -14
>>>>>
>>>>> yet the selling price of the -IQ is *half* of the -14
>>>>>
>>>>> true, the -14 looks to have a slightly spiffier case,
>>>>> and it might have a more stable, less noisy clock part,
>>>>> but that doesn't justify a $500 delta in the price
>>>>>
>>>>> what am i missing in this picture??
>>>>>
>>>>> -mo
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>> Mike:
>>>> I don't think they are not nearly as similar as you think. If I
>>>> remember, the SDR-14 uses a similar A/D (or maybe the same one), but
>>>> then the similarity ends. The A/D samples are processed differently,
>>>> using different DDC chips if I remember. The SDR-14 can deliver up to
>>>> a complete 33MHz bandwidth to the computer, if your computer can drink
>>>> that fast. The SDR-IQ can only deliver 192kHz, if I remember
>>>> correctly. I have an SDR-IQ, but could not afford an SDR-14.
>>>>
>>>> Whether the cost difference is accurate, or some premium is being
>>>> charged for the SDR-14 above the hardware differences is up to the
>>>> observer. I can look at both diagrams and give you more details, as
>>>> the above is from memory only.
>>>>
>>>> Terry
>>>>
>>>> _______________________________________________
>>>> Tacos mailing list
>>>> Tacos at amrad.org
>>>> http://www.amrad.org/mailman/listinfo/tacos
>>>>
>>>>
>>> Actually, I had it almost backwards (so much for my memory!). The A/D is
>>> different between the two. Both have the same DDC, but the -14 can
>>> bypass the DDC, allowing for the fast data rate. With the DDC
>>> in-circuit, I believe it's limited to about 160-192kHz as well. It also
>>> has a hardware FIFO for the samples. The SDR-IQ can only do 192kHz
>>> bandwidth, while it's possible to bypass the internal DDC on the SDR-14
>>> and go a lot faster. The SDR-IQ is a pretty neat device for the money.
>>>
>>> Another tidbit is that the preamp is after the various LP filters in the
>>> SDR-IQ, but before filtering in the SDR-14.
>>>
>>> Maybe the SDR-14 A/D is much better?
>>>
>>> Terry
>>>
>>
>>
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-- 
"Of course it's hard!
If it was easy, we'd be buying it from somebody else!"