A transmitter for transmitting signals via at least a first antenna and a second antenna, comprising: a first sequence generating unit configured to generate a first sequence for estimating a first channel condition, the first sequence being same as a sequence obtained by performing a first cyclic shift on a CAZAC sequence, the first cyclic shift being a first amount set for the transmitter; a second sequence generating unit configured to generate a second sequence for estimating a second channel condition, the second sequence being same as a sequence obtained by performing a second cyclic shift on the CAZAC sequence, the second cyclic shift being a second amount set for the transmitter and different from the first amount; a first block signal generating unit configured to generate a first block signal, the first block signal being same as a signal obtained by performing a third cyclic shift on a block signal generated from data, the third cyclic shift being a third amount; and a second block signal generating unit configured to generate a second block signal, the second block signal being same as a signal obtained by performing a fourth cyclic shift on the block signal generated from the data, the fourth cyclic shift being a fourth amount different from the third amount; wherein a period in which the first sequence and the second sequence are transmitted differs from a period in which the first block signal and the second block signal are transmitted; a gap between the first amount and the second amount differs from a gap between the third amount and the fourth amount; the first sequence and the first block signal are transmitted at least via a first antenna; and the second sequence and the second block signal are transmitted at least via a second antenna. a first sequence generating unit configured to generate a first sequence for estimating a first channel condition, the first sequence being same as a sequence obtained by performing a first cyclic shift on a CAZAC sequence, the first cyclic shift being a first amount set for the transmitter; a second sequence generating unit configured to generate a second sequence for estimating a second channel condition, the second sequence being same as a sequence obtained by performing a second cyclic shift on the CAZAC sequence, the second cyclic shift being a second amount set for the transmitter and different from the first amount; a first block signal generating unit configured to generate a first block signal, the first block signal being same as a signal obtained by performing a third cyclic shift on a block signal generated from data, the third cyclic shift being a third amount; and a second block signal generating unit configured to generate a second block signal, the second block signal being same as a signal obtained by performing a fourth cyclic shift on the block signal generated from the data, the fourth cyclic shift being a fourth amount different from the third amount; wherein a period in which the first sequence and the second sequence are transmitted differs from a period in which the first block signal and the second block signal are transmitted; a gap between the first amount and the second amount differs from a gap between the third amount and the fourth amount; the first sequence and the first block signal are transmitted at least via a first antenna; and <EOS>