One aspect of the present invention includes a bi-phase communication receiver system. The system includes an analog-to-digital converter (ADC) configured to sample a bi-phase modulation signal to generate digital samples of the bi-phase modulation signal. The system also includes a bi-phase signal decoder configured to decode the bi-phase modulation signal based on the digital samples. The system further includes a preamble detector comprising a digital filter configured to evaluate the digital samples to generate an output and to detect a preamble of the bi-phase modulation signal for decoding the bi-phase modulation signal based on the output.