In order to reduce the peak-to-average power ratio（PAPR） of orthogonal frequency division multiplexing（OFDM） signals

a piecewise-linear companding transform was proposed.Small amplitudes were multiplied by a scale factor

while large ones were not only multiplied by a scale factor but also added by a shift.The resulting companding transform was piecewise-linear and continuous.It can provide significant PAPR reduction performance with low compu-tational complexity

and has low influence on system performances through piecewise transform.It is shown by theoreti-cal analysis and simulation that

a good trade-off between PAPR reduction and bit-error-rate performances can be achieved by carefully choosing the two scales and the shift.Furthermore

compared with existing linear and nonlinear companding transforms

a better power spectral density performance can be achieved.