Aspen Electronics is now stocking the CM55 and CM65 clock modules from DAPU Telecom. According to Aspen, which has an exclusive UK distribution deal with DAPU, the new family of high accuracy clock modules will find application in LTE base stations and other applications that require high holdover. The modules can also replace atomic clocks in a range of high accuracy communications equipment applications.
LTE standards demand a frequency accuracy of ±50ppb with a time phase accuracy better than ±1.5µs/24h because base stations typically use satellite timing – backed up by a local clock in case the benchmark signal is lost temporarily. Typically those local clocks are crystal oscillators with high temperature stability rather than expensive atomic clocks.
Both the DAPU clock modules meet the LTE standard holdover requirement of ±1.5µs/24h. The CM55 is aimed primarily at indoor applications that may only experience small temperature changes (dT=±5OC), while the CM65 is suitable for outdoor applications, retaining its holdover characteristic across a temperature range from 0OC to 60OC.
Internally, the modules use an algorithm optimised for the application and can output highly accurate frequency signals of 1pps with adjustable pulse width. The module program can be remotely upgraded with both the CM55 and CM65 types being able to provide outputs of TOD information, customised to suit specific requirements.
Over an operating temperature range of -20 OC to 70OC the nominal frequency is 10MHz with a typical phase noise value of -150dB/Hz at 1kHz.
DAPU Telecom is a technology provider dedicated to producing high stability, high quality crystal oscillators. All products are RoHS certified with sample modules available now.