SDR-14 vs SDR-IQ
wb4jfi at knology.net
Sun Jan 17 16:26:36 CST 2010
> 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?
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