RDS Decoder Interfaced with 1957 Vintage Radio

The project illustrates how a very old and vintage radio was made to connect with a TDA7330B RDS demodulator along with an ATtiny2313 microcontroller making it an RDS decoder.

The design of the circuit includes a 2×16 HD44780 based LCD display that demonstrates the received and decoded RDS text. It comes with several options such as displaying RDS time, displaying traffic announcements (TA) flag, and scrolling 64 characters long RDS text. A vintage tube radio receiver from year 1957 was used for integration with this RDS receiver.

To start the connection to any FM radio, the phase discriminator or FM signal detector must be located first. There is stereo carrier signal on its output along with audio signal as well as MPX on 57kHz that carries RDS information. This is where the connection should take place through 470pF capacitor along with GND.

An alternative way is to connect to the hot point of the volume’s potentiometer by using the same capacitor if the discriminator output on any tube receiver could not be found. The one pin that is not middle or removable and not connected to GND is the hot point.

Rest of the project