Tuja SDR transceiver

A site is now launched for the Tuja SDR transceiver.

Tuja is an FPGA based software defined radio (SDR) transceiver characterised by a high dynamic range in receive mode and clean spectrum emissions in transmit. It is very different from other low or medium priced SDRs that often suffer from poor dynamic range and spurious emissions. Tuja has been optimized for narrow band communications and works great for weak signal modes like SSB, CW and low speed digital modes such as WSPR, FT-8 and PSK31. The high dynamic range also makes Tuja an excellent choice for VHF/UHF/SHF operation (in conjunction with a transverter). High speed digital modes such as 4G and WiFi are not supported.

Tuja integrates with the popular Raspberry Pi platform (like a “hat” but Eurocard format) for control and signal processing. The use of a Raspberry Pi enables flexible programming, easy spectrum presentation and remote operation. The Tuja board has an audio codec with microphone input and speaker/headphone output for stand-alone operation. It is possible to connect an LCD-display and a physical buttons/knobs for operation without any computer monitor or network connection.

Tuja is designed with modern components and well-proven radio architecture in mind. In receive mode it uses the superheterodyne architecture with ultra linear analog mixers and a steep intermediate frequency filtering. A bandwidth of 100 kHz is digitized to 24 bits where further filtering in an FPGA reduces it to 50-60 kHz usable bandwidth. Baseband data is sent to the Raspberry Pi as 24 bit I/Q samples over the I2S bus.

In transmit, the Raspberry Pi generates I/Q baseband data that is sent to the Tuja board for modulation of the carrier by analog mixers. Carrier frequency in transmit, as well as local oscillator signals in receive, are generated by the FPGA connected to a high-speed DAC, running on a very clean clock source.

Please visit the newly launched site for the Tuja SDR transceiver.

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