This is a general purpose design though the first application was to use a 2MHz bandwidth Cable Modem (DOCSIS) on FDD 874MHz and 919MHz.
Full duplex using a duplex filter on the aerial connecting to RF LNA and RF PA. The Modem connects via a typical cable broadband Diplexer. A single chip dual PLL/Synth controls the up converter and downconverter VCOs that drive the doubly balanced diode ring mixers. A PIC micro sets the PLL/Synth dividers and prescalers.
An onboard superhet / FSK receiver measures a beacon carrier and thus the CPU can select high or low gain for the receiver converter.