| 摘要 |
<p>A device for generating an electrical signal of a required form, preferably a sine wave suitable for a ringer, comprising an amplifier for producing an output signal of a required form, a power supply generator for supplying a power supply voltage to the amplifier, and a circuit for producing a first feedback signal to control the power supply voltage based on the output signal. Additionally, the amplifier provides comparison of a reference input signal with a second feedback signal formed from the output signal. <IMAGE></p> |
