This paper presents a 4 Gbps adaptive equalizer with a pre-equalizing by frequency-to-voltage converter(FVC). FVC makes a gain control signal for a pre-equalizer according to their input frequency. The FVC predicts a chanel compensation for the input data rate following a DFE equalizing. The proposed equalizer shows 0.7 UI output of data signal at 4 Gbps in 10mm on-chip under a 180nm CMOS technology.