An auto-Sensitivity Control Circuit Using Analog Topology for Wired CDMA Bus Interface

An auto-sensitivity control circuit using analog topology for wired CDMA bus interface is proposed. Because, the bus capacitance is directly proportional to the number of transmitter/receiver pairs, the receiver circuit of CDMA requires different sensitivities for different number of transmitter/receiver pairs. We proposed an analog circuit that controls the effect of using different number of transmitter/receiver pairs. The proposed circuit consists of variable gain amplifier (VGA) and gain control circuit in CDMA receiver. Simulation results using 3.3 V supply voltage, 128 code length and 50 MHz operating speed reveals that using the proposed circuit, the receiver in CDMA bus interface works well with wide input range and good linearity.