The FS5000 Jitterlyzer performs

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechani ...

serial bus In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits ar ...

jitter In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a signifi ...

evaluation. It can inject controlled jitter and measure the characteristics of incoming jitter. When teamed with a

logic analyzer A logic analyzer is an electronic instrument that captures and displays multiple logic signals from a digital system or digital circuit. A logic analyzer may convert the capture into timing diagrams, protocol decodes, state machine traces, op ...

protocol analyzer A protocol analyzer is a tool (hardware or software) used to capture and analyze signals and data traffic over a communication channel. Such a channel varies from a local computer bus to a satellite link, that provides a means of communication u ...

, it can correlate these measurements with protocol analysis. Physical-layer tests can be performed while the system under test is processing live bus traffic."FuturePlus Systems and DFT Microsystems collaborate on next generation High Speed Serial IO Jitter Tools". Internet Business Systems, Inc. 2007. edacafe.com

/ref>

Jitter measurements

The FS5000 measures jitter in two categories:

Timing

''There are four different timing measurements'': *Bathtub Plot - The

bathtub curve The bathtub curve is a particular shape of a failure rate graph. This graph is used in reliability engineering and deterioration modeling. The 'bathtub' refers to the shape of a line that curves up at both ends, similar in shape to a bathtub. Th ...

can provide tremendous insight into the BER performance of a link under test. A bathtub curve is obtained by drawing a horizontal line across the waveform under test. The probability distribution function for signal transitions (zero crossings) from a high voltage to a low voltage or a low voltage to a high voltage is then computed. The bathtub curve is useful because it can provide a lot of insight into the behavior of a system. Apart from estimating BER, it also provides an indication for the amount of margin that is in the system. When coupled with protocol testing with the Jitterlyzer, a high margin enables engineers to quickly rule out the physical layer as a potential cause of certain protocol errors. * Statistics - The Jitterlyzer’s measurement routines uncover total jitter and BER directly (without requiring mathematical extrapolation). This routine for random jitter (RJ) and deterministic jitter (DJ) separation is included for completeness. Also a number is provided for RJ and DJ on real-life traffic. * Bus View - Shows channel to channel skew of four channels simultaneously. *Jitter Histogram - This routine is performed on real-life traffic. It selects the zero-crossing voltage in the incoming data. It then counts the number of transitions of the high-speed serial signal as a function of phase positions. A histogram of number of hits versus delay is then plotted.

Eye

''There are three different eye measurements'' *

Eye diagram In telecommunications, an eye pattern, also known as an eye diagram, is an oscilloscope display in which a digital signal from a receiver is repetitively sampled and applied to the vertical input (''y-axis''), while the data rate is used to tri ...

- This routine is performed on real-life traffic. It provides much more information than just a vertical eye opening or a horizontal eye opening. Instead, it provides a first indication of parameters such as dispersion in the signal path, rise-time issues, etc. Click on the link and you will see an example of an eye diagram that is obtained using the Jitterlyzer. As can be seen, an indication of noise throughout the whole eye is made, as opposed to, for example, only at the center. *

Oscilloscope An oscilloscope (formerly known as an oscillograph, informally scope or O-scope) is a type of electronic test instrument that graphically displays varying voltages of one or more signals as a function of time. Their main purpose is capturing i ...

- This measurement allows the user to see an oscilloscope trace in persistent mode, allowing direct inspection of the eye. Color represents the frequency with which the measured trace passes through each point, with red representing the most frequent, and black representing the least. Note that frequency is normalized to a maximum value of 1. * Voltage Histogram - This measurement is similar to the jitter histogram except that it is done in the vertical domain. It shows the amount of voltage noise that exists on the high-speed serial signal and is similar in principle to the vertical eye height."Features - FS5000 JitterlyzerTM". FuturePlus Systems Corporation. 2006. FuturePlus.com

Jitter generation

Data pattern

*LIVE traffic *Preprogrammed Compliance patterns

Jitter profile

*Frequency range 19.07 kHz - 19.99 MHz *Amplitude range 40ps - 1200ps

Differential swing

*400-1600mv

External links

Jitter analysis
tool from FuturePlus Systems.

References

{{reflist Digital electronics Electronic test equipment