August 2018
DSP Radio Receiver
In summer 2018, the poor performance of my old radio receiver became a real headache: I was attending the CET 6 English Test in the coming months, in which a good receiver is a must. This gave me adequate motivation to build my own one.
I surveyed on the Internet and selected a receiver DSP chip, Si4702, manufactured by Silicon Labs. It has sufficient SNR and sensitivity for daily operation. We need an external microcontroller to set up its parameters and running mode. They communicate through a specialised I2C protocol.
A Nokia is not always an outmoded design. I chose a matrix LCD, PCD8544 , that was massively used on old Nokia models. Implementing the communication protocol, as well as font specification, are major difficulties in this part.
Since I didn’t plan to equip the radio receiver with a speaker, any low-power headphone amplifier would do. NXP’s TDA1308 is a good choice after experiment. There was an unexpected benefit: The headphone serves as an antenna, so we don’t have to explicitly mount one.
