GPS2000C01

Ultrastable GNSS or IEEE 1588 based frequency standard with redundancy capabilities for generation of 10 MHz, 1 PPS sync and IEEE 1588 signal

The GPS2000C01 module is a high stability time and frequency master that can be disciplined by other primary masters using GNSS signals or via PTP. It has been designed for synchronization of telecommunications networks in general and in particular for use in digital radio and television production and broadcasting environments.
The long-term stability of the GPS2000C01 is provided by the primary masters discipline it, which are normally cesium clocks. The short-term stability is obtained with a high quality oven-controlled crystal oscillator (OCXO). This oscillator is also responsible for maintaining operation of the module if the GNSS or PTP signals are lost.
The GPS2000C01 includes a highly stable oscillator whose frequency can be set by a control voltage (VCOCXO) and from which all of the reference signals provided by the module are obtained. One of these signals is a one pulse-per-second (1 PPS). The phase of the 1 PPS signal is compared with that of the signal coming from the GNSS or the Ethernet interface via PTP in order to correct the phase of the VCOCXO. In addition to this correction, the module learns the drift of the OCXO frequency over time and temperature in order to provide a precise model of the OCXO's behavior. This model is employed to correct small changes in the oscillator so that the module can continuing delivering a good quality signal when it loses the reference, as long as the interruption is not too long. This operating mode in which the module delivers signals without being synchronized to any reference is known as Holdover Mode.
As described previously, the module admits two 1 PPS reference signals: one that comes from the GNSS satellite array and the other that comes via Ethernet using the PTP protocol. The phase of both reference signals with respect to the phase of the oscillator signal can be measured simultaneously, but only one of this signals can be used to discipline the VCOXCO. The module can be configured to use only the 1 PPS signal from the GNSS receiver, to use only the 1PPS signal from PTP or to use the 1 PPS signal from GNSS whenever it is available and in its absence to use the one from PTP. The module can also be programmed to ignore both signals and operate in Holdover Mode.
The GPS2000C01 provides two outputs via BNC connectors on the front panel that can be configured to deliver two 1 PPS signals with TTL levels, two sinusoidal 10 MHz signals or one 1 PPS signal and one 10 MHz signal.
In addition to the front panel connectors, the GPS2000C01 delivers 1 PPS, 10 MHz and 13.5 MHz signals to the bus of the mounting frame in which it is installed. These signals can be used by other modules for synchronization or for distribution to other equipment. The 13.5 MHz can be used for all audio and video equipment and furthermore it includes the UTC date and time information necessary to generate timecode signals.
Two GPS2000C01 modules can be installed in adjacent slots in a UR2000 mounting frame in order to provide 1+1 redundant generation of the 1 PPS, 10 MHz or 13.5 MHz signals. When operating redundantly the two modules continually exchange information in order to deliver the most precise signals possible at any given moment. In Redundant Mode there are two 1 PPS outputs and two 10 MHz outputs protected by a bypass relay on the front of the modules as well as 1 PPS, 10 MHz and 13.5 MHz signals on the mounting frame bus. All signals are generated by whichever module is active at that time.
When the GPS2000C01 is governed by GNSS is can function as a PTP master and as a NTP server.
The modules provides two outputs with contacts closed to GND in order to indicate that it is delivering a valid signal and when it is being governed by an external reference signal.