SDR-14 vs SDR-IQ
mo at ccr.org
Sun Jan 17 17:04:53 CST 2010
sounds like it's time to get the ADI application notes
and build an add-on board for the OMAP Linux machine.
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??
>> 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.
>> Tacos mailing list
>> Tacos at amrad.org
> 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?
"Of course it's hard!
If it was easy, we'd be buying it from somebody else!"
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