on (see the upcoming section "Budgeting End-to-End Time Error"). The metric hax|TEL means that a low-pass filter with bandwidth of 0.1 Hz is applied to the TE measurement samples from the 1PPS output prior to evaluating the max|TE|. The limits for noise transfer of T-BC-A/T-TSC-A focuses primarily on the maximum noise that the clock can transfer from the local time reference (1PPS) as input to the output at the 1PPS and PTP master port. This noise transfer is calculated and specified in terms of phase gain. According to G.8273.4, the phase gain should be smaller than 0.1 dB (1.1%). Transient Response For the T-BC-A/T-TSC-A, the transient is defined as the loss of the local time reference for a short period before it is restored. For the T-BC-A, the transient response is measured at the PTP and 1PPS output, whereas for T-TSC-A it is measured at the 1PPS output. The requirement covers the com- plete cycle from reference loss, through holdover, and back to reacquiring the signal and locking to The clock undergoes a sequence of events during this transient. G.8273.4 specifies the transient re- sponse for the each of the main steps, which are as follows: The local time reference (such as a GNSS receiver) is lost. The transient response due to a loss of the local time reference shall be less than 22-ns MTIE. The clock enters holdover and maintains a holdover state for the short term. The performance requirement during this holdover is the same as the regular holdover of the clock. This is dis- cussed in next section on holdover. The local time reference is restored, and the clock selects the local time reference. The transient response due to the selection of the local time reference (after restoration) shall be less than 22- ns MTIE. The clock locks to the local time reference and the normal operation of the clock continues. Holdover A clock moves to holdover when it loses all its reference signals and must rely on its own devices to maintain phase and frequency. Because the T-BC-A/T-TSC-A also has a local time source