On Sat, Aug 6, 2016 at 12:03 AM, Slichter, Daniel H. (Fed) <daniel.slich...@nist.gov> wrote: > This is very nice work, thanks for the detailed write-up. It seems that this > gateware design would cover just about any use case for high-bandwidth > two-tone designs. To Dave L's question, there are already interpolation > filters with sharp cutoffs in the AD9154 to eliminate Nyquist images if > desired; I have done some measurements on the AD9154 hardware and they work > quite well, up to what the datasheet says (~85 dB image rejection in the > stopband, which would take us effectively to the noise floor of the outputs > generated by the gateware Robert demonstrates). TI gives the filter > coefficients for their FIR filters in the datasheets; you might be able to > email Analog Devices and ask them for the filter coefficients for the AD9154, > and this would allow you to evaluate the phase and amplitude response vs your > needs.
Those AA filters won't do anything to the images from the f1/f2 oscillators. I assume Dave was referring to those. > It does highlight the need for the DAC clock to be programmable over a wide > range, from ~800 MHz up to 2.4 GHz (this is most important for Greg and Tom > to be thinking about). Sure. Designing it for just one DAC clock would be shortsighted (unless there are overwhelming technical reasons to do so). Robert. _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
