Embodiments of the present invention disclose a sending apparatus and a receiving apparatus, and a method for sending a physical layer signal, includes: constructing a signal with a frame structure comprising multiple Ga128 sequences, a —Ga128 sequence, and a single-frequency sequence of M in length; wherein the Ga128 and —Ga128 sequences are Golay sequences of 128 in length, M is an integer multiple of 128, and the single-frequency sequence comprises M single-frequency symbols and is used to enable a receiving apparatus to estimate an Inphase and Quadrature (IQ) imbalance parameter; and sending the signal with the frame structure.