ginngi engineering

Our customer develops and markets diagnostic tools for monitoring traffic over various communications infrastructures. We were contracted to develop a module that interfaced to a DS3 carrier to perform both monitoring and testing of the system-under-test without disturbing the line.

The module's architecture consisted of two physical DS3 channels each of which has a separate TX and RX BNC connector. Using internal switches it is possible to configure the two channels to operate either as a pass-through for monitoring or to stimulate the network with test data. In either case data that entered the module was extracted, parsed and analyzed for specific data relevant to the system under test. In this way we were able to extract the 28 E1/T1 channels that existed for each of the DS3 channels and to provide detailed information for each channel simultaneously.

The board design consisted of a high-frequency analog front end interfacing to the line, differential input amplifiers that converted the analog to a clean digital signal, DS3 processing engines from Mindspeed and an FPGA for various glue-logic functions.

A Windows software driver was written to bridge between the module and a Windows application.

The PCB layout consisted of a 12-layer stackup. Ground planes provided shielding of EMC and careful impedance matching for critical analog and digital signals. Clocks were carefully layed out using shielded techniques.