DIGITAL WIRELESS NARROW BAND RADIO

摘要

A network communication card is provided for facilitating ultra high frequency (UHF) radio communication between a terminal and a base station, the network communication card being in communication with an antenna and comprising a double-sided multilayer printed circuit board (PCB). The PCB comprises a digital interface, a receiver and a transmitter. The digital interface provides communication between the PCB and the terminal. The receiver receives incoming radio signals from the base station and processes the received signals for communication to the terminal via the digital interface. The transmitter transmits outgoing radio signals from the terminal via the digital interface to the base station and includes the following components. A digital synthesizer provides a highly accurate modulated carrier signal. An upconversion circuit increases the frequency of the carrier signal. A filter filters spurious content from the carrier signal. A phase locked loop (PLL) comprising a synthesizer and a voltage controlled oscillator (VCO) generates a transmission signal from the filtered carrier signal. A transmission circuit transmits the transmission signal via the antenna.