A new PLL synthesizer for fast FH spread spectrum communications

A phase-locked loop synthesizer for fast frequency-hopped spread-spectrum (SS-FH) communications is proposed. This synthesizer is composed of digital signal processing components except for the voltage-controlled oscillator (VCO). The phase-error signal between a reference signal and a feedback signal (VCO output) is derived by the subtraction of those phase components. The low-pass filter employed in conventional PLL synthesizers is not needed because harmonics and nonlinear distortions do not appear at the phase detector. Therefore, this synthesizer is able to have about about a 10³~10⁴ time faster hopping speed and produce more stable frequencies than conventional PLL synthesizers