SDR-14 vs SDR-IQ

[Frank Gentges]

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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