Time-correlation of data

摘要

Test and measurement instrumentation collects time information independently in each clock domain using a device that monotonically changes state with the passage of time according to a local clock domain. The device under test therefore has a unique state for each synchronous time period. The instrumentation periodically samples the devices under test, collects the state of each device, and records the state of the devices in conjunction with any data collected in clock domains that are synchronous with the devices. The periodic samples are transformed into numeric values using an isomorphic or linear model. These values are then fitted to an assumed frequency model that relates the state of devices in otherwise unrelated clock domains.

主权项

1. The method for time-correlating data, the method comprising:
sampling state information from a plurality of embedded instruments situated within different clock domains; transforming the sampled state information into numerical values; fitting the numerical values to a model; time-correlating a plurality of events based at least in part on the model; and inferring one or more simultaneous events, among the events, across the different clock domains; for each of a first plurality of clock cycles, time-stamping, by a first embedded instrument from among the plurality of embedded instruments, the first embedded instrument being situated in a first clock domain, first events associated with the first plurality of clock cycles; for each of a second plurality of clock cycles, time-stamping, by a second embedded instrument from among the plurality of embedded instruments, the second embedded instrument being situated in a second clock domain different from the first clock domain, second events associated with the second plurality of clock cycles; storing the first time-stamped events in a first buffer as first state information associated with the first embedded instrument; storing the second time-stamped events in a second buffer as second state information associated with the second embedded instrument; reading the first state information from the first buffer associated with the first embedded instrument situated within the first clock domain; reading the second state information from the second buffer associated with the second embedded instrument situated within the second clock domain; inferring the one or more simultaneous events across the first and second clock domains; generating a time-correlated view of the events, including the one or more simultaneous events; and displaying the time-correlated view on a display for visual inspection.