Alternating digital RF modulation
View Patent ↗A pulse step modulator employs a plurality of series connected unit step power amplifier modules. Each module is turned on by a turn-on signal to provide a unit step voltage of a given value. An output circuit is connected to the modules for providing an output voltage to a load and wherein the output voltage is a multiple of the unit step voltages in dependence upon the number of modules that are turned on. The modules are sequentially turned on in a given order and are turned off in the reverse order. An encoder provides turn-on signals with each turn-on signal being applied to a selected one of the modules. The number of turn-on signals provided varies as a function of the magnitude of a time varying input signal. A controller alternately turns enables or disables (in a swapping manner) one of a pair of associated modules as the magnitude of the input signal increases and decreases.
1. A pulse step modulator comprising a plurality of series connected unit step power amplifier modules with each said module being turned on by a turn-on signal to provide a unit step voltage of a given value;
an output circuit connected to the modules for providing an output voltage to a load and wherein said output voltage is a multiple of said unit step voltages in dependence upon the number of modules that are turned on;
said modules being sequentially turned on in a given order and are turned off in a reverse order as a time varying input signal increases and decreases in value;
an encoder that provides turn-on signals with each turn-on signal being applied to a selected one of the modules with the number of turn-on signals provided varying as a function of the magnitude of the input signal; and
a controller that alternately enables and disables (in a swapping manner) one of a pair of associated modules as the magnitude of the input signal increases and decreases.
2. A modulator as set forth in claim 1 , wherein said pluralities of modules includes N modules where N is an even number.
3. A modulator as set forth in claim 1 , wherein each said turn on signal turns on an enabled one of a said pair of associated modules.
4. A modulator as set forth in claim 3 , wherein said pluralities of modules includes N modules where N is an even number.
5. A modulator as set forth in claim 1 , wherein said plurality of modules includes N modules divided into pairs of associated modules.
6. A modulator as set forth in claim 5 , wherein said pluralities of modules includes N modules where N is an even number.
7. A modulator as set forth in claim 3 wherein said N modules includes modules 1 to N respectively associated with incrementally increasing magnitudes of said input signal.
8. A modulator as set forth in claim 7 , wherein N is an even number.