An electronic device comprises a first circuit portion comprising one or more components, including a first counter, which are clocked by a first clock signal. The first circuit portion is arranged to receive a data stream comprising a plurality of data signals. A second circuit portion comprises one or more components clocked by a second clock signal and a second counter not clocked by the second clock signal. The first clock signal is not synchronised to the second clock signal. The second circuit portion is arranged to: receive samples of the data stream from the first circuit portion at a sample rate and to time-stamp each received sample with a count value of the second counter. The second circuit portion increments the count value of the second counter by a predetermined increment value for each received sample.