For a diagram of how some of these interact in the FPGA, see SmartSDR FPGA Architecture

A foundation receiver is created entirely in the FPGA. It consists of a DDC on one of the SCUs and a decimation chain that can have one or more FFT or slice receivers connected to it. Foundation receivers are not exposed in the client API or to users of SmartSDR GUI applications.

A low-speed (6MHz) mixer attached to a foundation receiver with a 24kHz IQ output that is used for slice receiver input. Slice receivers connect to Mini Mixers which, in turn, connect to Foundation Receivers. Mini Mixers are not exposed in the client API or in SmartSDR GUI applications.

A slice receiver is connected to a foundation receiver and includes a DDC for the frequency of the slice receiver, a demodulator and additional DSP functions such as noise blanking and AGC Spectral Capture Unit (SCU) : A spectral capture unit begins with an antenna connector and ends with the Analog to Digital Converter (ADC). It includes all preamplifiers, attenuators, preselectors and hardware filters.