In some examples, a system includes a receiver configured to receive signals encoding first, second, and third messages in first, second, and third frequency bands. The system also includes a mixer configured to down-convert the received signals to intermediate-frequency (IF) signals based on a local oscillator signal. The system further includes at least one analog-to-digital converter configured to sample the IF signals at a sampling rate. A frequency band of the IF signals encoding the first message falls within a first Nyquist region, and a frequency band of the IF signals encoding the second message falls within a second Nyquist region. The first and second Nyquist regions are frequency ranges bounded by multiples of one-half of the sampling rate, and the second Nyquist region is different from the first Nyquist region. The system includes processing circuitry configured to determine data in the first, second, and third messages based on an output of the at least one analog-to-digital converter.