A communication unit (700) is described that includes a plurality of cascaded devices that comprise at least one master device (710) and at least one slave device (720, 723) configured in a master-slave arrangement. The at least one master device (710) and at least one slave device (720, 723) each comprise: an analog-to-digital converter, ADC, (741, 742) configured to use a same re-created system clock signal (788, 790) to align respective sampling instants between each ADC (741, 742). The at least one master device (710) comprises: a clock generation circuit comprising an internally-generated reference phase locked loop circuit (708), configured to output a system clock signal (782, 784); and a modulator circuit (762) coupled to the clock generation circuit and configured to receive and distribute the system clock signal (784). The at least one master device (710) and at least one slave device (720, 723) each comprise: a demodulator circuit (764, 765) configured to receive the distributed system clock signal (784) and re-create therefrom a synchronized system clock signal (788, 790) used by a respective ADC, (741, 742) of each of the the master device (710) and at least one slave device (720).