History of HPSDR Mercury and Quick Silver Philip Covington, N8VB Early HPSDR and XYLO In 2005 I started a High Performance SDR (HPSDR) project which was to consist of a motherboard carrying a FPGA/USB 2.0 interface and power supply with the provision for plug in modules through 40 pin headers. I had planned a narrow band high dynamic range module based on a QSD/DDS/PCM4202 audio ADC and a wide bandwidth module based on a high speed 16 bit ADC: http://www.philcovington.com/SDR/PICS/HPSDR_FPGA_USB_Board_top1_800600.jpg http://www.philcovington.com/SDR/PICS/HPSDR_FPGA_USB_Board_top4.jpg I soon selected the LTC2208 ADC from Linear Technology. A representative from Linear Technology came across my blog ( http://pcovington.blogspot.com/ ) and offered evaluation boards and samples to support the project. At about the same time my HPSDR project came about, Phil Harman, VK6APH and Bill Tracey, KD5TFD were interested developing a sound card replacement to be used with the SD...