A pulse width modulation system.

摘要

A first source (1) of voltage V supplies sufficient rectified power for the carrier to the R.F. stage (7) of a radio transmitter. A second source (9) which exceeds twice the voltage V, powers a pulse width modulation amplifier (8) serving to amplify an incoming audio signal (A). The amplified signal (A) is applied, via a capacitor (16), to the load, thereby modulating the voltage V. Because the voltage of the second power source more than exceeds twice the voltage V, the amplifier can be operated at less than 100% pulse width modulation whilst still obtaining an amplification sufficient to achieve 100% modulation of the voltage V applied to the load.