I finally had the courage to open up the radio and look inside (Hint: some screws are hidden under the speaker grilles). There is a Samsung module that plugs into a PCB named "Table-Top Version 2.2". The Main PCB contains the Power Supply, Amplifier, and connectors for the display, speakers, keypad, etc. The Samsung HDRMDVM0101 module contains the heart of the radio. The module has a 20 pin and a 50 pin connector to interface to the Main PCB. The module also has a JTAG connector for the ATMEL Processor.
ICs on the module include:
ATMEL Mega128L Low Power AVR RISC Processor with 128K Flash
TI TMS320DRI350AZTS5 DSP for HD Radio Baseband and Analog Decoding
TI DRI8201 Intergrated AFE
Spansion S29GL032M90TFIR4 3.3V 32Mb Flash x8/x16 Bottom Boot Sector
ESMT M12L128324A 3.3V 4MBx32 SDRam
1803A 24bit 96K Stereo Audio ADC
1782 24bit 96K Stereo Audio DAC
LM833 Dual Op Amp
This is a Software Defined Radio where the AM or FM signal is converted to a 10.7 MHz IF and then digitized. The digitized IF gets downconverted and fed to the DSP where either AM, FM or HD signals are decoded and sent to the Stereo Audio DAC. It appears even the Aux Input is digitized. Several companies offer modules based on the HD reference design so I would not be surprised if most HD radios use the same scheme. Plug a module into a I/O board and put a custom user interface/configuration in flash.
Tags: radioascolto, radiofonia, radio, dxing.