The present disclosure relates to sending methods and apparatus. One example method includes receiving first indication information for uplink data transmission, where the first indication information indicates a frequency resource for the uplink data transmission, and the frequency resource includes N subcarriers, and sending an uplink reference signal associated with the uplink data transmission, where a length of a sequence of the uplink reference signal is M, a roll-off factor of a filter for the uplink data transmission is not greater than 2 ⁢ ⁢ M N - 1 , and N/2≤M