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That HankRF link is very interesting.
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That project and GNU radio may have ideas you can borrow, even if you do not use their hardware.
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this software defined radio is being constructed for maritime commercial applications, so it must meet maritime standards. The bandwidth of interest is 6MHz and the channel bandwidth is 25 kHz. Im oversampling by using 40MSps for process gain.Would this mean that the FPGA board must match the 6MHz bandwidth?
The 25 kHz channel will be digitally filtered and demodulated. I'm not sure at this stage whether to sample the channel down to baseband, or digitally convert down to base band.
I was hoping to use a low cost solution so I may need to use an HSMC or a 100-mil expansion headers if im to use something like the cyclone family. Do you have suggestions on FPGA boards I should be looking for?
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While this is something that a 40MHz ADC plus an FPGA can do, its also something that devices from Lime Microsystems (the chip that hack RF uses), Analog Devices, Texas Instruments, and Linear Technology can implement directly. These devices have ADCs followed by mixers, decimation sinc filters, and FIR filters for sinc-filter correction.
For example, take a look at the AD6649 (I know this does not match your requirements - its just what I found after quickly looking on the Analog Devices site);
http://www.analog.com/en/analog-to-digital-converters/integrated-receivers/ad6649/products/product.html If you're looking for low-cost, and "software" is processing the output samples, then that would seem to me to be the more appropriate device to use.
If you want to use an FPGA to do this, then you could use a low-cost board like the DE0-nano and interface that to a 40MHz ADC. In fact you do not even need to interface to an ADC to test DSP algorithms, since you can use RAM within the FPGA to store input and output samples, eg., see these class notes (with links to code)
http://www.ovro.caltech.edu/~dwh/correlator/pdf/esc-104paper_hawkins.pdf http://www.ovro.caltech.edu/~dwh/correlator/pdf/esc-104slides_hawkins.pdf Cheers,
Dave
Honored Contributor
