Patent ID: 7203465
Filing Date: 2007-04-10
Classification: H04B

Abstract:
1. A receiver/transmitter circuit, comprising: an antenna terminal; a transmitter circuit which outputs a transmission signal in response to a transmit control signal; a receiver circuit which receives a reception signal from the antenna terminal; a waveform control circuit which outputs a switching signal having a gradual logic transition in response to the transmit control signal; a first switch connected between the antenna terminal and the transmitter circuit, wherein the first switch transfers the transmission signal to the antenna terminal in response to the switching signal; and a second switch connected between the antenna terminal and the receiver circuit, wherein the first switch includes a first transistor which has a first terminal connected to the antenna terminal, a second terminal connected to the transmitter circuit and a control terminal, and wherein said second switch includes a second transistor which has a first terminal connected to the antenna terminal, a second terminal connected to the receiver circuit and a control terminal, and wherein the waveform control circuit includes a resistor and a capacitor, wherein a first end of the resistor is connected to the control terminal of the first transistor, and a second end of the resistor is connected to receive the transmit control signal, and wherein the capacitor is connected between the first end of the resistor and a ground voltage node.