Vermes
Advanced Member level 4
The main element of the receiver is a popular FM head of type DT2000 controlled by synthesizer SAA1057. Two filters 10,7 MHz and TDA1200 are used in intermediate frequency, and the whole is controlled by microcontroller Atmega8. Alphanumeric LCD display 2x16 characters is used for communication with user.
Receive band is broadened in range from 87.00 MHz to 109.00 MHz. Retuning step is set permanently at 10 kHz. The set frequency can be written in 20 channels.
The receiver has 9-point signal meter, which uses the measuring output of TDA1200 (pin 13) and one of the Atmega ADC. Also a noise-canceling function of TDA1200 is used in the form of intensity adjustment by potentiometer. Those properties mainly decided about applying TDA1200 in intermediate frequency block.
The receiver has RDS decoder on TDA7330A. This system was used because of small amount of external elements, availability of the system and low cost. Programmatically, PI, PS, RT and CT (only clock) are decoded from RDS. The limitation is a result of size of the FLASH ROM Atmega8, space on the display and that the receiver's driver was written in BASCOM.
Link to original thread (useful attachment) – Przenośny odbiornik ukf z RDS na atmega8
