Patent ID: 8228118

Claim:
A method of obtaining an output signal from a direct current (DC) current source, wherein the output signal is a linearly amplified replica of an input signal, comprising the steps of: receiving the input signal; transforming and pulse modulating the input signal for generating a pulse modulated signal, wherein said transforming is based on that when applying a constant current to a capacitor means, the energy stored in the capacitor means is proportional to square of the applying time; switching the constant current from the direct current (DC) current source to the capacitor means according to the pulse modulated signal; blocking a current from the capacitor means to a filter when the constant current from the direct current (DC) current source to the capacitor means is switched on and conducting the current from the capacitor means to the filter for transmitting energy stored in the capacitor means to the filter when the constant current from the direct current (DC) current source to the capacitor means is switched off for generating a pulsed output signal; filtering the pulsed output signal for outputting the output signal by the filter.