COMMUNICATIONS APPARATUS

摘要

In a first aspect the invention provides an apparatus for processing radio signals for connection to a personal computing device (PCD), in which a stream of digitised intermediate frequency (IF) data is maintained in at least one direction. In the inbound direction, information is received (104) as radio frequency (RF) signals by the device, down-converted (105) to IF and then digitised (107) and fed into the PCD (109) under control of an interface management unit (IMU 108). Software modules in the PCD then provide whatever demodulation processing is required for the transmission scheme in use. The invention further provides a transmitter apparatus. In the outbound direction, an IF signal is digitally synthesised by software on the PCD (109), according to an appropriate modulation scheme, and the resulting signal is passed to the device via the IMU, where it is used to generate (110) a corresponding analogue waveform. This waveform is then up-converted (112) to RF at the appropriate frequency and transmitted. As the PCD software is able to send commands to the device to set the centre frequency and bandwidth of RF to be accepted and transmitted, the device (together with appropriate software on the PCD) provides the basis for a generic, low-cost radio-frequency communications system. The invention may further provide a transceiver apparatus having both inbound and outbound channels.