A portable HF transceiver with digital IF

Details the results of a study concerning the architecture of an HF (1.5-30 MHz) portable transceiver based upon digital signal processing (DSP) of a low IF signal coming from a classic analog front end. Design goals were to get at least as good performances as in traditional analog portable transceivers. Traditional 3 kHz SSB mode is enhanced. The output can either be an analog voice signal or a digital stream for a direct connection to a modem. Special care has been taken in the design to adapt the analog part to the analog to digital converter (ADC). Due to the consumption and performance constraints a sigma-delta type converter associated with a single DSP processor would be a good choice to form the digital part of the receiver. The transmission mode uses a reversed version of the same chain in order to minimize the overall number of parts which in turn minimizes the volume and price of the transceiver