A new whitepaper from MaxLinear Inc. (NYSE: MXL), a leading provider of integrated radio frequency (RF) and mixed-signal integrated circuits for broadband communications applications, provides an in-depth look at the issue of television signal interference caused by proximity to 4G LTE signals, as countries around the world shut off analog terrestrial TV services and switch to all digital transmission.
When digital television frequency bands are adjacent to LTE bands, as is the case with the 700 MHz and 800MHz LTE frequency bands, there is a high likelihood that LTE signals can interfere with television signals. Digital TVs and set-top boxes must have sufficient interference rejection capabilities in the tuner, or additional signal filtering to eliminate the problem. Some countries that have recently deployed LTE services are finding that the cost can be up to $500 per home to fix the problem retroactively.
The whitepaper, entitled LTE Interference on Digital TV in Brazil ( which can be downloaded from the MaxLinear website), is a result of the collaboration between Dr. Glenn Chang, Cofounder and Senior Director of Technical Marketing at MaxLinear and Prof. Dr. Gunnar Bedicks, Chief Researcher at Mackenzie Presbyterian University’s DTV Laboratory in Sao Paulo, Brazil.
Their study measured LTE interference in five use cases that involved indoor/outdoor digital TV antennas in the presence or absence of a booster (amplifier). Four of the use cases were for single-family homes, and the fifth was for a multi-dwelling unit scenario.Critical receiver performance parameters were taken into consideration, including sensitivity, maximum signal strength and receiver linearity. The paper discusses possible mitigation techniques, such as those offered by MaxLinear, which can result in robust receiver performance even in the presence of a harsh LTE interferer. “Countries moving from analog to digital television coverage are discovering that LTE signals can interfere with digital TV reception,” said Brian Sprague, MaxLinear Vice President and General Manager, Broadband and Consumer Products. “MaxLinear has developed advanced tuner technology that can mitigate this interference, allowing digital TV and STB OEMs to provide a higher quality picture that keeps customers happy.”