The LFRX daughterboard is a low-cost daughterboard that provides direct access to the ADC inputs. The board can accept real-mode or quadrature signals from DC to 30 MHz. The LFRX is ideal for applications using an external front end providing relatively clean signals within operable bandwidth. High-speed opamps couple each RF input to a single channel of the USRP device's ADC. The signals sampled by the ADC are manipulated in the FPGA, and can be processed as two real-mode signals, or a single I-Q pair.

The LFRX does not include a local oscillator or downconverter.