Comark originally introduced the PARALLAX liquid-cooled, solid-state DTV transmitter product line at NAB 2015. PARALLAX AIO is a simplified and compact version of the transmitter and is intended for medium power DTV requirements. The benefit of the AIO design is that it incorporates the complete liquid cooling system and RF filtering inside the transmitter cabinet in lieu of external subsystems. The benefit of the PARALLAX AIO is that on-site installation time is drastically simplified; the field engineer only needs to connect the transmitter’s RF output to the transmission line and two cooling hoses to the outdoor heat exchanger.

The AIO can be equipped with 3 to 8 Power Amplifiers (PA’s) in a single transmitter cabinet, delivering from 5.4 to 13kW TPO. PARALLAX AIO continues to ensure top-notch performance since the PA’s utilize the latest asymmetric broadband Doherty LDMOS FET devices. These devices not only provide broadband high efficiency operation but also have the benefit of providing the equivalent output power in ATSC 1.0 (8VSB) and ATSC 3.0 (OFDM).

The DTV transmitter’s RF system, fully contained in the transmitter rack cabinet, accommodates either 6 or 8-pole variations. The RF system also includes a motorized RF output switch and liquid cooled station load, with switch control fully integrated into the transmitter’s control system.

According to Tom Barbeau, Hitachi Kokusai Electric Comark VP of Engineering, “international DTV conversions, non-repack, and NextGen TV requirements demand streamlined transmission solutions and the PARALLAX AIO product delivers. We have engineered the best possible solution using state of the art amplification, efficient cooling, and RF mask filtering in a package that gets a site on-the-air in just a few days.”