RF Shorts for Aug. 1, 2014

Auto-Balancing Doherty Amplifiers Have Arrived
Steve Bush writes in Electronics Weekly that a new Chip offers accurate Doherty balance on-the-fly. Doherty amplifiers are used to improve solid-state amplifier efficiency. They use at least two devices: one to amplify the average signal and another that handles peaks. Maximum efficiency requires precise phase and amplitude control. The new chip from Peregrine Semiconductor targets macro and small-cell base stations.

According to information from Peregrine: “The current solution employs discrete components to tune phase and amplitude for carrier and peaking paths. The Peregrine PE46120 monolithic phase and amplitude controller includes a 90-degree hybrid splitter, two phase shifters, two amplitude controllers, and an SPI digital interface. Both paths can be optimized on the fly through the SPI to compensate for operational or environmental changes.”

More details can be found in Steve Bush's article. All current high power broadcast Doherty amplifiers that I'm aware of use discrete devices to control phase and amplitude.

Iridium GO! Connectivity Is Now Available
Iridium Communications announced its Iridium GO! Is now available. The device operates as a hotspot, allowing up to five devices to connect to Iridium's satellite constellation anywhere in the world. It supports voice calls and texting as well as low-bandwidth Internet access through Iridium Mail & Web.

According to Iridium this is a “first of its kind product” and it’s also the least expensive device and service offered by Iridium.”

“Iridium GO! enables people to use their smartphones and tablets when they are outside of cellular coverage through the complete global reach of the Iridium network,” said Bryan Hartin, executive vice president of sales and marketing at Iridium. “Additionally, the Iridium GO! platform is unique in the control it provides iOS and Android app developers. No other satellite provider offers a program like this that allows app developers to manage their access with the Iridium network.”

More information is available on the Iridium GO! site. The price varies from company to company. For example, Range Global Services is offering a $825 Iridium GO! launch promotion that waives the activation fee and includes a $50 rebate. Their website showed monthly plans ranging from $99 per month for 60 minutes each month up to $199 per month for 200 minutes of service. Overage costs range from $1.20 per minute to $0.99 per minute. The base plan charges $0.50 per SMS text. More expensive plans include a limited number of SMS messages and lower per message rates beyond that.

Comments and RF related news items are welcome. Email me at dlung@transmitter.com.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.