Patent ID: 7683676
Filing Date: 2010-03-23
Classification: H03F,H04B

Abstract:
1. A signal-level detecting apparatus that detects either one of a peak level and a bottom level of an input signal, the signal-level detecting apparatus comprising: an amplifying unit that performs a differential amplification with either one of a previous peak level and a previous bottom level of the input signal and a current input signal; a semiconductor element that includes a first terminal, a second terminal, and a third terminal, the semiconductor element transferring a signal level output from the amplifying unit from the second terminal to the third terminal by using a current that is conducted from the second terminal to the third terminal in response to a voltage applied to the first terminal; a control unit that includes: a holding unit that holds a signal level output from the third terminal of the semiconductor element, wherein the second variable current becomes lower when the threshold voltage becomes higher, while the second variable current becomes higher when the threshold voltage becomes lower.