Pulses are detected in a communications receiver by programming each of a plurality of comparators (44a, 44b, . . . , 44n) with a sampling time point selected from a plurality of sampling time points (58, 60) and with a reference level selected from a plurality of reference levels (54, 56). The received signal is applied to each of the comparators such that each of the comparators produces a respective output signal based on a comparison between the received signal level and the selected reference level at the selected sampling time point. The combinations of sampling time points and reference levels can be selected based on knowledge about the expected arrival times of the pulses, and based on knowledge about the possible shapes of said pulses, with the result that the device can detect received pulses without requiring large amounts of hardware, in a device which has an acceptable power consumption. The communications system may be a signaling system, or a radar or positioning system.