Pictured above is the front-end, first mixer and IF amplifier of an experimental GPS receiver. The leftmost SMA is connected to a commercial antenna with integral LNA and SAW filter. A synthesized first local oscillator drives the bottom SMA. Pin headers to the right are power input and IF output. The latter is connected to a Xilinx FPGA which not only performs DSP, but also hosts a fractional-N frequency synthesizer. More on this later.