SQMP: Synchronization & Qualtiy Meter
S.Q.M.P. is the hardware platform fitted with the Phase Hardware Module (PHM) and used by the Synchronization Quality Meter(SQM) to qualify the frequency stability of telecom networks and synchronization equipments (SSU, BITS , …).
Typically this is an instrument that characterizes the timing stability of a clock signal, by measuring the TIE (Time Interval Error) with respect to a Reference clock.
The TIE measurement circuitry, actually the phase error comparator, and the Reference clock are integrated into the PHM module. The processing of the TIE measurement is achieved by a classical PC running the SQM application software.
The results of each TIE measurement can be :
The clock under test can be a 2MHz G.703 signal, a 2Mb/s G.703 signal (framed G.704 or unframed), a 1.544Mb/s T1 signal (SF, ESF or unframed – with the optional T1 interface), or a 5MHz signal (announced).
The reference clock is generated by an inner Oscillator section, consisting of a DPLL(Digital Phase Locked Loop) which can be either locked to an external signal or free-running.
The external locking signal for the DPLL can be a 2MHz G.703 signal, a 2Mb/s G.703 signal (framed G.704 or unframed), a 5MHz signal, or a GPS signal coming from an optional additional module.
The DPLL is controlled by a Rubidium source; therefore, the frequency stability and accuracy of the Oscillator when free-running are in compliance with the G.812 class.
The S.Q.M.P. is also able to output the clock generated by the internal Oscillator. (available frequencies are 2 MHz G.703 signal – convertible to a 1.544Mb/s T1 signal with the optional T1 interface- and 5MHz). As a consequence, the S.Q.M.P. can also offer synchronization signal to telecom network equipments in a way similar to a Synchronization Supply Unit (SSU).