Fast frequency hopped–spread spectrum (FFH-SS) communication is a system that can realize excellent interference immunity, disturbance immunity, and security. In the implementation of this system, there must be a synthesizer that can switch the frequency with high speed. From such a viewpoint, the authors previously proposed a fast hopping PLL synthesizer, based on the initial value presentation in which the phase difference obtained by the phase comparator at the same frequency output of the previous period is reproduced by utilizing the periodicity of the frequency hopping. It is shown that the hopping frequency can be raised to one-third the reference frequency. In this method, however, the phase error of the VCO output generated in frequency switching produces an error in the phase difference reproduced by the phase comparator, which results in a stepwise error in the output frequency. In order to deal with this problem, a circuit for the phase error compensation was proposed, but there remained problems such as the difficulty of high-frequency operation. This paper proposes a fast hopping frequency synthesizer that solves those problems. In the proposed method, the phase difference is not reproduced by the phase comparator, and there is no effect from phase error of the VCO output generated in frequency switching due to the use of the difference of the phase errors. Faster operation is realized, with the hopping frequency equal to one-half the reference frequency. This helps to reduce the number of bits in the A/D converter below that of the D/A converter. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 82(10): 10–19, 1999