The design and implementation of TV tuner for digital terrestrial broadcasting

The DTV tuner for 8-VSB modulation was developed with satisfying the requirements of the ATSC. The double frequency conversion and the active tracking filter in the front-end were used for the cancellation of the interferences between adjacent channels and multi-channels by suppressing IF beat and image band. However, it was impossible to get frequency mapping between the tracking filter and the first VCO in the existing DTV tuner structure differing from the NTSC tuner. This paper, therefore, suggests the available structure and a new method for automatic frequency selection by obtaining the mapping of frequency characteristic over the tracking voltage and the combined hardware which is composed of a microcontroller, EEPROM, D/A, op amp and switch driver.