Design & implementation of fast frequency hopping Tx IF module for satellite terminal based on DVB-RCS

In this paper the method for the minimization of satellite Tx IF module is presented. The proposed Tx IF module can support fast frequency hopping up to ±10 MHz around the center frequency within guard time, 6 usec. For minimizing Tx IF module, base-band I-Q signals are quadrature modulated to 820±11.2 MHz band, after modulation it is up-converted to 950∼1450 MHz by wide band PLL. To support fast frequency hopping, the local oscillator (LO) of QPSK modulator is composed of DDS (Direct Digital Synthesizer) and fixed PLL (Phase Locked Loop). The Tx IF module includes a 5-bit digital attenuator, RF switch and BPF. We implemented both digital part and analog part were mounted in one PCI card.