What are FPGAs and their use in amateur radio?

FPGA stands for Field Programmable Gate Array, meaning that it is an integrated circuit which can be reprogrammed after manufacturing. Field programming means programming outside the manufacturing facility in the factory. This allows us to customize its functionality to perform specific tasks as in amateur radios. It has even been mentioned that you can make radios without a soldering iron and wires, using FPGAs. In fact people have actually made AM radios with an FPGA and very few other components! FPGAs are useful in Digital Signal Processing (DSP) and are capable of handling large amounts of data in parallel processing. Conventional computer Central Processing Unit (CPU) uses sequential processing rather than parallel processing. FPGAs can be used to build highly flexible and customizable Software Defined Radios (SDRs).