Third order distortion in digital receiver front-ends as the dominant interference mechanism above 470 MHz

Wireless transmission systems for DTV and data may carry digital information, but the radiated signal is an analog signal supported by amplitude modulation or amplitude & Phase modulation of a (suppressed) carrier as in the 8-VSB modulated ATSC DTV System, DVB-T and ISDB-T which are DTV transmission Standards developed in the USA, Europe and Japan. The analog portion of receiver generally consists of a variable gain RF amplifier, a frequency converter (mixer) driven by a Local Oscillator and an IF Filter and IF amplifier. The amplified IF signal is fed to an Analog-to-Digital converter from which the digital transport stream is available for processing digitally. The analog portion of digital receivers is vulnerable to interference from strong signals on other channels.