The present invention, generally speaking, incorporates the power
amplifier as a fundamental constituent of a modulator, using
polar modulation techniques. Thus, it is possible to achieve the combination of precision
signal generation (including envelope variations) along with
high energy efficiency in combinations not possible heretofore. In accordance with one embodiment of the invention, a modulated radio (
passband)
signal generator produces high quality signals of general type, which specifically includes signals with varying envelopes. Signals are generated with
high energy efficiency in the conversion of applied DC power to output RF
signal power. The result is longer battery life for products such as
mobile phone handsets. Dramatically improved efficiency also allows for a dramatic reduction (10 to 1 or greater) in the size of any required heatsink for the radio
transmitter, which significantly lowers both cost and size. Furthermore,
continuous operation of these radio transmitters is made possible with small temperature rises using small heatsinks, or even without any heatsink components. This provides for high operating reliability, as well as for greater
throughput due to the longer
operating time allowed. Another aspect of the invention allows the generation of high quality signals with wide bandwidth, without the need for
continuous feedback during operation. This further reduces costs by greatly simplifying the design, manufacturing, and complexity of the
transmitter circuitry.