| 摘要 |
<p>It includes a loudspeaker (18) receiving signals from an amplifier (17), the amplifier having a supply input connected to a ringing line (1) providing a ringing signal via a chopped supply unit (5), and a clocking input (16) also connected to the ringing line (1) via a regulating unit (9, 2, 4, 6) giving an image signal of a power of the ringing signal, and a transformation unit (8) transforming the image signal under a clocking signal applied to a terminal (15). <IMAGE></p> |
