Abstract: The peak to average power ratio (PAPR) of a signal is one of the key indexs in information and communication systems. General chaotic signal has higher PAPR value due to large dynamic variation range. To reduce the PAPR value of the chaotic signal effectively, we present a frequency chaotic signal with constant amplitude and chaotic modulated frequency. The realization of frequency chaotic signal by using chaotic circuit to generate an amplitude chaotic signal to drive voltage-controlled oscillator (VCO) is proposed. Basic dynamical characteristics and main application performances of the frequency chaotic signal is analyzed. A circuit to generate the frequency chaotic signal is designed by using Chua’s chaotic circuit as the amplitude chaotic signal source, from which phase portrait of the amplitude chaotic signal and time-domain waveforms of the frequency chaotic signal are obtained. Theoretical analyses and experimental results indicate that the frequency chaotic signal has the same maximum Lyapunov exponent as the amplitude chaotic signal, the same PAPR value as that of sinusoidal oscillation signal, and thumbtack like ambiguity function. Therefore, the application of frequency chaotic signal as radar signal will have good transmission and detection performance.