Apparatus for timestamp processing

An apparatus comprising:

• a. at least two time-to-digital converters (TDCs) that have start and stop inputs and output the time difference between an edge of the start input and an edge of the stop input;
• b. a reference clock that is applied to one of the inputs of each TDC;
• c. a counter that counts the edges of the reference clock;
• d. an electronic circuit or a computer program executed on a processor that converts said time differences into extended time values taking into account the counter value;
• e. the electronic circuit or the computer program executed on the processor that merges said extended time values into a stream of time stamps, where each timestamp consists of an extended time value and a value that identifies the TDC from which it originated;
• f. the timing jitter of the timestamps is smaller than 100 ns;
• g. at least two input signals that are applied to at least two individual TDC inputs;
• h. at least one input signal is periodic or quasi periodic, whereby a quasi periodic signal is a periodic signal in which at least one of the edges is missing;
• i. the electronic circuit or the computer program executed on the processor is continuously executed that and receives a timestamp data stream as an input and generates a new timestamp data stream as an output;
• j. the latency of the electronic circuit or the computer program executed on the processor is less than ls, meaning that when a new timestamp or a new block of timestamps is provided as an input to the data processing, its calculation is performed in less than 1 s, thereby producing an output timestamp or a block of output timestamps;
• and
• k. the electronic circuit or the computer program executed on the processor comprises one or both of the following two calculations:
• i. for a periodic or quasi periodic input signal:
• a continuously updated calculation, whereby estimated timestamps (t′p,1) are generated from at least a subset of the initial timestamps (tp,1). The estimated timestamps (t′p,1) encode the underlying periodic signal and their timing precision is higher than that of the initial timestamps (tp,1);
• and
• ii. continuously updated rescaling calculation of the timestamps of at least one channel, whereby its timestamps (ts,1) are converted to the time reference frame represented by the periodic or quasi periodic input signal, thereby generating rescaled timestamps (t*s,1).