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<\/a><\/p>\nGemini naturally expands the Microtelecom’s product line of sampling receivers towards higher frequencies.<\/p>\n
The Gemini receiver features two RF inputs, each of them independently processed by a low-noise and high dynamic range RF front-end and sampled by a high speed, 14 bit, two channels A\/D converter operating at 200 MSPS. Each of the two RF front-ends of Gemini are equipped with a six bands preselection filters bank ranging from 28 to 170 MHz, a high IP3 LNA and a 0-30 dB, 1 dB steps variable attenuator.<\/p>\n
Wideband Inputs for Direct Access to the A\/D Converter Gemini features two unconditioned wideband inputs (1-500 MHz, 3 dB bandwidth) which give a direct access to the A\/D converter inputs for multiple channel perations with external RF signal conditioning. For the maximum flexibility the wideband inputs are equipped with independent variable attenuators.<\/p>\n
Meeting the Need of Higher Speed Digital Signal Processing. The RF signals simultaneously sampled by the Gemini A\/D converter are numerically processed at 200 MSPS\/channel by a high speed multichannel digital down-converter implemented in a FPGA of Xilinx’s most recent Spartan6 amily. The digital down-converter outputs are decimated down to 1 MSPS\/channel or less and streamed to the PC processing plaftorm through a high-speed (480 Mbit\/s) USB2.0 port.<\/p>\n
Ultra Low Jitter Clock for the Highest Dynamic Range up to VHFs<\/p>\n
As the frequency of the signals to be sampled increases, the quality of the A\/D converter sampling clock needs to be higher and higher.
\nGemini A\/D converter is driven by a sampling clock derived from the industry best crystal oscillator, a ultra low noise 400 MHz voltage controlled oscillator locked to an internal 10 MHz, 1 ppm TCXO.<\/p>\n
Optionally, when more than two inputs need to be simultaneously processed by more units, the receiver sampling clock can be locked to a 10 MHz external reference clock and the samples streams synchronized to an external trigger signal.<\/p>\n