A 77 GHz waveform generator with MFSK modulation for automotive radar applications

In this paper, a 77 GHz waveform generator with Multiple Frequency Shift Keying (MFSK) is presented. This modulation waveform can improve the detection ability of automotive radar systems. A MFSK Modulation Control Logic (MMCL) is proposed, incorporates a conventional Σ-Δ fractional-N Phase Locked Loop to generate the modulation waveform. The MMCL has capability to track the linear frequency sweep while generating the frequency shift keying (FSK) in each time step. Prior to realizing the hardware, a behavioural simulation is considered and the output of 64 steps is generated. The modulated frequency synthesizer is designed using 130-nm CMOS process. The module of 77 GHz waveform generator, which generates 128 modulation steps, is accomplished. The bandwidth and the frequency step of the modulation are 100 MHz and 300 kHz, respectively. The results demonstrate that the proposed scheme has ability to realize the MFSK modulation waveform for automotive radar systems, also a short processing interval of 6 ms can be achieved.