RF modem for high capacity radio system

Presents a new high-capacity microwave system in the upper 6 GHz band based on microwave modulation and demodulation. This equipment is designed in two versions, organised around a common TX/RX, and differing only in the framing and error code correction modules. The first version transmits the highest level (140 Mbit/s) of plesiochronous digital hierarchy (PDH) and uses 16QAM modulation. The second version transmits an STM-1 signal (first level of the synchronous digital hierarchy-SDH). This version is originally intended for use in an SDH network but can be used in a transitory step to transmit 140 Mbit/s signals, mapped into an STM-1 frame. It is based on 32 TCM-4D coded modulation. The paper focuses mainly on the RF modules, addressing MMIC (monolithic microwave integrated circuit) products as an alternative to discrete ones. It presents their relationship with signal processing, including original solutions that have been devised for high level RF modulation and demodulation