Fig. 1 Functional Block Diagram
The ASNT_PRBS40_1 is a broadband 27-1 PRBS generator intended for test, prototyping, microwave, and communication applications. A single-ended clock from 2GHz to 22GHz is used. This single-ended Clock Input feeds a static differential Divide by 4 Output, an adjustable differential divide by 2 to 512 Sync Output, a differential clock that supplies the multiplexer responsible for doubling the data rate up to 44Gbps, and a differential clock that triggers the PRBS 27-1.
The Clock Input, Sync Output, and Divide by 4 Output are AC coupled on board. The PRBS Output is DC coupled operating with a common mode level above ground. On board trim potentiometers allow adjustment of the clock’s duty cycle that feeds the multiplexer. They also adjust the phase shift delay for both data paths fed into the multiplexer. This adjustment capability ensures the best operating point for the desired waveform output. An on board PRBS reset switch is included to preset the generator to avoid the all zero state lock-up.