A calibration apparatus, comprising: a sending module, a receiving module, and a processing module, wherein the sending module is configured to send a first detection signal to a first multiplexing device; the receiving module is configured to: receive the first detection signal that passes through the first multiplexing device, and detect a power of the first detection signal that passes through the first multiplexing device; the processing module is configured to adjust a center frequency of the first detection signal based on a detection result, so that an adjusted center frequency of the first detection signal is aligned with a center frequency of the first multiplexing device; the sending module is further configured to: when the center frequency of the first detection signal is aligned with the center frequency of the first multiplexing device, send a second detection signal to the first multiplexing device and a second multiplexing device, wherein the center frequency of the first multiplexing device is aligned with a center frequency of the second detection signal; and the receiving module is further configured to: receive the second detection signal that passes through the first multiplexing device and the second multiplexing device, and detect a power of the second detection signal that passes through the first multiplexing device and the second multiplexing device; and the processing module is further configured to adjust the center frequency of the second detection signal based on a detection result, so that an adjusted center frequency of the second detection signal is aligned with a center frequency of the second multiplexing device; and the processing module is further configured to adjust the center frequency of the first multiplexing device based on the adjusted center frequency of the second detection signal, so that the center frequency of the first multiplexing device is aligned with the center frequency of the second multiplexing device. the sending module is configured to send a first detection signal to a first multiplexing device; the receiving module is configured to: receive the first detection signal that passes through the first multiplexing device, and detect a power of the first detection signal that passes through the first multiplexing device; the processing module is configured to adjust a center frequency of the first detection signal based on a detection result, so that an adjusted center frequency of the first detection signal is aligned with a center frequency of the first multiplexing device; the sending module is further configured to: when the center frequency of the first detection signal is aligned with the center frequency of the first multiplexing device, send a second detection signal to the first multiplexing device and a second multiplexing device, wherein the center frequency of the first multiplexing device is aligned with a center frequency of the second detection signal; and the receiving module is further configured to: receive the second detection signal that passes through the first multiplexing device and the second multiplexing device, and detect a power of the second detection signal that passes through the first multiplexing device and the second multiplexing device; and the processing module is further configured to adjust the center frequency of the second detection signal based on a detection result, so that an adjusted center frequency of the second detection signal is aligned with a center frequency of the second multiplexing device; and the processing module is further configured to adjust the center frequency of the first multiplexing device based on the adjusted center frequency of the second detection signal, so that the center frequency of the first multiplexing device is aligned with the center frequency of the second multiplexing device.