Peak sidelobe level (PSL), integrated sidelobe level (ISL) and signal to noise ratio (SNR) are the main performance indices in pulse compression radar. Pulse compression is useful in providing two contradicting requirements, namely, higher transmitted power required for longer pulse transmission, and smaller range resolution which is a desirable characteristic of smaller pulse transmission. The sidelobe suppression method proposed in this paper is based on the correlation processor that uses the P4 polyphase codes. P4 codes are known for their better Doppler tolerant property. Sidelobes are undesirable as jammers or noise present in sidelobes may interfere with the desired target. The proposed method has been implemented with six different windows namely Hamming, Hanning, Blackman, Nuttall, Blackman–Nuttall, and Blackman–Harris and results show that PSL value of − 275.6 dB and ISL value of − 152.98 dB are achieved without much degradation in SNR value. Ambiguity function is derived for the designed sequence and the results are compared with the Frank, Barker and P4 code in the delay-Doppler plane. Results show that the proposed method provides significant performance improvement compared to existing sidelobe suppression methods.