Abstract: A delay calibration circuit, a memory, and a clock signal calibration method are provided. The delay calibration circuit includes: a divided clock generation circuit, configured to receive an input external clock signal and output at least two channels of divided clock signals based on the external clock signal; a calibration circuit, connected to the divided clock generation circuit and configured to adjust delays of at least two channels of divided clock signals based on a trimming signal and output adjusted divided clock signals; and a detection circuit, connected to the calibration circuit and configured to detect pulse widths of the at least two channels of divided clock signals and generate the trimming signal based on the pulse widths.

Abstract: Provided are a method for assaying a specific IgM antibody and a total antibody for the 2019 novel coronavirus (2019-nCOV), a method for determining whether subjects are infected with 2019-nCOV, and a virus antigen and a kit for carrying out the above-mentioned detection.