I have two high-speed sampling devices that can use UDP (through 1G Ethernet) and PCIe to transmmit their samples, respectively. They are used to record signals I interested. These devices are made by myself so the data format and the software running on OS are easy to be modified. Now I want to use GNU radio to demodulate some signals from the devices in real-time but I don't now the interface and format of GNU Radio. Is it possible to do that? Is it necessary to read or even modify its source code? And which document should I read?