Trigger/decoder for scope analysis of Manchester- and NRZ-coded buses

August 03, 2015 // By Graham Prophet
Manchester and NRZ coding are used by a large number of commercially-available, and proprietary, serial buses for the transfer of data and control signals. Debugging options for these protocols have been limited, according to Rohde & Schwarz, introducing its universal trigger and decoder option for the R&S RTO and R&S RTE digital oscilloscopes.

With the R&S RTx-K50, the oscilloscopes help users debug serial protocols that employ Manchester or NRZ coding. The option can be used with a variety of standardised buses such as PROFIBUS, DALI or MVB as well as with proprietary serial protocols such as are typically found in industrial environments and in the aerospace and defence sector.

The option, which covers data rates of up to 5 Gbit/sec, supports up to 50 different telegram formats, while the format of the serial bus can be configured flexibly. Users can define their own preamble, frame ID, data, CRC and other telegram fields. Protocol decoding also takes Manchester code violations into account.

High acquisition rates and minimal blind times are provided by the hardware-based trigger implementation on the R&S RTO and R&S RTE oscilloscopes. Users can trigger on telegram and data content with the R&S RTx-K50 option. The decoded protocol content is displayed in a colour-coded format. Time correlation with the analogue signal helps identify faults caused by signal integrity problems. A tabular list of the protocol contents is also provided. The standard mask test with up to 600 000 tests per second makes it possible to check the signal quality faster with an eye diagram than with any other solution. Both oscilloscope series from Rohde & Schwarz support the option of decoding up to four different serial protocols in parallel.

Rohde & Schwarz;