[aprssig] APRS SDR

[Matti Aarnio]

On Mon, Dec 13, 2010 at 01:53:42PM -0800, Jeremy McDermond wrote:
> On Dec 12, 2010, at 8:05 AM, Matti Aarnio wrote:
> 
> > Having a special SDR hardware that takes application bits in on one end,
> > and puts IF/RF waveforms out on other is usually seriously more expensive
> > approach.  A mid-scale Xilinx Virtex-IV, and 100 Msps ADCs/DACs does cost
> > several kilo-dollars, or more commonly tens of kilo-dollars.
> 
> It's not that bad.  The OpenHPSDR project is using the following parts:
> 
> LTC2208 (130 Msps 16-bit A/D converter): $130
> AD9744 (210 Msps 14-bit D/A converter): $12.68
> Altera EP3C40 (39600 gate Altera FPGA.
> Largest leaded array available from Altera):  $78.50
> 
> Those are prices from DigiKey today.  The current OpenHPSDR system in
> totality is in the low kilo-dollars range.  One of the new designs should
> hopefully bring a price in the less than kilo-dollar range.

While I might consider blowing my yearly hobby electronics project budget
on OpenHPSDR or SDR-IQ, commercially viable "APRS SDR" is still a _cheap_
microprocessor that has ability to AD/DA of baseband waveforms, and do DSP
processing on them.  Total system price assembled, tested and delivered to
my mailbox under USD 100.

A system where one ADC alone costs more than that.  Very few will buy it.
Not to mention its power requirements.

See OpenTracker and TinyTracker.  They are commercially viable.
They even do modem bits partly in software.

There are so many ways that one can understand what "SDR" means...
Some apparently understand it to include applications like UI-View.

> Jeremy McDermond (NH6Z)

73 de Matti, OH2MQK