Frequency-hopping spread-spectrum modulation for digital communications over electrical power lines

A solution for the precise and cost-effective generation of frequency-hopping spread-spectrum waveforms using digital frequency synthesis based on read-only-memories (ROM, PROM, EPROM) is studied. For matched filter reception of frequency-hopping spread-spectrum waveforms a new approach based on lock-in amplifiers combined with synchronous voltage controlled oscillators (SVCO) brought remarkable results in practical field tests. An application-specific digital signal processor for receiver operation in form of a CMOS gate array was also designed. Prototypes according to two different system concepts were built, and measurements of bit error probability were carried out on indoor and outdoor power-line networks. Computer simulations based on channel analysis to predict bit error probability are proposed and compared with measured results. Indoor prototypes are designed for a data rate of 300 b/s and a frequency-hop rate of 900 s^-1 with a transmission voltage ≈0.35 V_rms in a spectral range from 30 to 146 kHz. Outdoor prototypes are intended for remote meter reading featuring a data rate of 60 b/s and a frequency-hop rate of 300 s^-1. Transmission voltage is variable from 0.35 to 1 V_rms in a spectral range from 30 to 146 kHz