A method for synchronization to upstream transmission bursts, the method comprising: a1) receiving by a network testing device a first upstream burst signal comprising a first upstream signaling burst, wherein the first upstream signaling burst includes a delimiter bit sequence, and a2) using the delimiter bit sequence for burst signal synchronization, wherein the method is characterized in that the delimiter bit sequence is unknown to the network testing device, the first upstream signaling burst includes a sequence of at least partially fixed bits at known fixed bit positions relative to the delimiter bit sequence; and wherein a2) comprises: b) finding in the received burst signal a matching bit pattern that matches at least one pre-defined target bit sequence, wherein the at least one pre-defined target bit sequence corresponds to the sequence of at least partially fixed bits in the first signaling burst; c) retrieving the delimiter bit sequence from the received first signaling burst based on a position therein of the matching bit pattern found in step (b) and the known position of the at least partially fixed bits relative to the delimiter bit sequence in the first signaling burst, and saving said delimiter bit sequence in a memory; and, d) using the saved delimiter bit sequence to synchronize to subsequently received upstream transmission bursts. a1) receiving by a network testing device a first upstream burst signal comprising a first upstream signaling burst, wherein the first upstream signaling burst includes a delimiter bit sequence, and a2) using the delimiter bit sequence for burst signal synchronization, the delimiter bit sequence is unknown to the network testing device, the first upstream signaling burst includes a sequence of at least partially fixed bits at known fixed bit positions relative to the delimiter bit sequence; and wherein a2) comprises: b) finding in the received burst signal a matching bit pattern that matches at least one pre-defined target bit sequence, wherein the at least one pre-defined target bit sequence corresponds to the sequence of at least partially fixed bits in the first signaling burst; c) retrieving the delimiter bit sequence from the received first signaling burst based on a position therein of the matching bit pattern found in step (b) and the known position of the at least partially fixed bits relative to the delimiter bit sequence in the first signaling burst, and saving said delimiter bit sequence in a memory; and, d) using the saved delimiter bit sequence to synchronize to subsequently received upstream transmission bursts. b) finding in the received burst signal a matching bit pattern that matches at least one pre-defined target bit sequence, wherein the at least one pre-defined target bit sequence corresponds to the sequence of at least partially fixed bits in the first signaling burst; c) retrieving the delimiter bit sequence from the received first signaling burst based on a position therein of the matching bit pattern found in step (b) and the known position of the at least partially fixed bits relative to the delimiter bit sequence in the first signaling burst, and saving said delimiter bit sequence in a memory; and, d) using the saved delimiter bit sequence to synchronize to subsequently received upstream transmission bursts.