Detection circuit and related electronic apparatus

A detection circuit, configured to determine an amplitude of a received signal generated by a receiver after the receiver receives an input signal, wherein the detection circuit comprises:

• an operational amplifier, having a positive end, a negative end and an output end;
• a capacitor unit, coupled between the output end and the negative end of the operational amplifier;
• a reset switch, arranged in parallel with the capacitor unit;
• a first switch, coupled between a reference voltage and an output end of the receiver;
• and
• a second switch, coupled between the output end of the receiver and the negative end of the operational amplifier;
• wherein:
• in a reset stage, the reset switch is turned on and the second switch is turned off, the output end of the operational amplifier outputs the reference voltage;
• and
• in a general stage, the reset switch is turned off, and the received signal comprises a plurality of waves with a period of T, and in a period T corresponding to a first specific wave of the plurality of waves, the detection circuit is set to a sampling mode for time period of T*R and set to a non-sampling mode for time period of T*(1−R), wherein R is greater than 0 and smaller than 1;
• and in a period T corresponding to a second specific wave of the plurality of waves, the detection circuit is set to the sampling mode for a time period of T*R and set to the non-sampling mode for a time period of T*(1−R), wherein:
• in the sampling mode, the first switch is turned off and the second switch is turned on, so that the amplitude change of the received signal during the sampling mode is reflected in a specific proportion and is accumulated at the output end of the operational amplifier;
• and
• in the non-sampling mode, the first switch is turned on and the second switch is turned off, so that the amplitude change of the received signal generated by the receiver in the non-sampling mode does not respond and does not accumulate at the output end of the operational amplifier, so that the voltage at the output end of the operational amplifier remains constant in the non-sampling mode.