Abstract: Methods reduce transients in a redundant clock system forming part of a switch in a telecommunication network. In general, the transients, normally in the form of phase steps, are caused by reconfigurations in the clock system. Examples of reconfiguration are an inclusion or an exclusion of a redundant clock generating circuit, referred to as a plane, or an activation of a network synchronization. These transients are eliminated by successively adding an increment to a variable representative of a physical quantity in the clock generating system. In the case of an inclusion of a plane or an activation of the network synchronization, a positive increment is successively added to the gain of an amplifier. In the case of an exclusion of a plane, an increment is successively added to a phase difference representing signal.

Abstract: A phase detector for measuring phase differences between K input signals is provided. The phase detector includes a counter, K first registers and a first subtractor. Each first register receives the counter signal of the counter and a respective input signal for updating a counter value in response to timing information on the input signal. The first subtractor receives the counter values to generate phase difference representing values. A frequency detector is also provided. The first subtractor is substituted by a second subtractor and K second registers are included. Each second register is connected to a respective first register. Each second register receives the counter value of its first register and the same input signal as that of its first register for backing-up the counter value as a back-up counter value in response to the timing information on the input signal.

Abstract: A phase detector for measuring phase differences between K input signals is provided. The phase detector includes a counter, K first registers and a first subtractor. Each first register receives the counter signal of the counter and a respective input signal for updating a counter value in response to timing information on the input signal. The first subtractor receives the counter values to generate phase difference representing values. A frequency detector is also provided. The first subtractor is substituted by a second subtractor and K second registers are included. Each second register is connected to a respective first register. Each second register receives the counter value of its first register and the same input signal as that of its first register for backing-up the counter value as a back-up counter value in response to the timing information on the input signal.

Abstract: Quality requirements on a counter may set a limit to the highest frequency that can be applied to the counter. This will also limit the resolution. A counter is provided including a generator for generating, in response to a first clock frequency, M second clock signals phase shifted with respect to each other and of a second frequency lower than the first frequency, and M secondary counters, each one responsive to a respective one of the M second clock signals for generating a secondary counter signal. The second frequency is adapted to work well in the technology available for realizing the secondary counters, with consideration taken to quality requirements. Furthermore, the counter included a summing circuit responsive to the secondary counter signals for generating the resulting counter signals by adding the secondary counter signals such that the counter signal has the same number of bits and the same significance as the secondary counter signals.