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The Class M Power Module consists of the modulator, driver and switch-mode PA shown below. The switch-mode amplifier is a new class for digital amplifiers invented by the engineers of PulseWave RF necessitating a new designation - Class M. PulseWave RF delivers on its promises through extensive digital integration in the Class M Modulator. The modulator is an upconverter, a linearizer, and a digitizer, implemented in a proprietary integrated circuit. It combines the inputs of I and Q signals at IF from a multiplying DAC and real-time feedback from the power amplifier (PA) producing a digital pulse wave. The Class M Driver is a custom IC that has been specifically designed to amplify the high frequency digital pulse waves to drive the high efficiency Class M Switch-Mode PA.
A New Architecture for Base Station Transmitters
With the upconverter functionality built into the module, Class M Power simplifies the design of multi-carrier base station transmitters - taking the baseband signals directly to RF. After baseband processing, which usually includes crest factor reduction, the RF transmitter section simply consists of a multiplying DAC, the Class M Power module, and an isolator, inserted before the output filter.
Since Class M Power is a self-contained linearized digital MCPA module; it allows designers to easily meet the different power requirements for micro-cells, macro-cells, remote transceiver heads, and repeaters by a parallel combination of Class M Power modules. To illustrate the scalability of the modular approach, the example above shows a 40 Watt multi-carrier transmitter chain realized by combining two 20-Watt modules. The resulting overall efficiency for the RF transmitter section is 22%. The Class M Module can scale from 5 to 20 watts and with multiple modules scale up to 160 Watts of average power. Gain and phase matching of the modules are accomplished via software-control. |
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