Figure 1 gives the circuit connection, where each
operational amplifier is designed as alternating current
amplifier. When there is no alternating current input, the
output is 1.5V (VCC=3V). While inverting input via a 1.5 link
short circuit to ground, this simulates the antenna. Antenna
would select and demodulate RF signals under working
frequency[5]. We could get the noise filtering capability of the
circuit by measuring the voltage of the output port.