[Hackrf-dev] 5 MSPS sample rate

[Jared Boone]

On Aug 5, 2013, at 6:52 AM, Sean Nowlan <sean.nowlan at gtri.gatech.edu> wrote:


> I'm just guessing, but maybe he meant sampling just one channel instead of quadrature at higher resolution. Not sure if the chip even supports such a configuration.


You're correct, the MAX5864 is only an 8-bit ADC. With oversampling of the target signal, you can achieve some amount of processing gain, I believe on the order of one bit for every quadrupling of the sampling rate. But ultimately, it's still an 8-bit ADC, with the attendant limitations that imposes. With a *substantial* redesign, one could accommodate a higher precision ADC, or a single ADC channel (with much more advanced IF filtering), but you'll have a decrease in maximum sample rate to allow for the limit of approximately 40 MiB/second over USB 2.0 high speed. The trade-offs made with 8-bit conversion seem to be the right ones for the goals of HackRF -- low price, low power consumption, wide tuning range, high sampling rate, to serve the security research community.

	- Jared