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<< Contents
<< Other Topics
<< Specs and Limits
<< GoLogicPro Specs and Limits
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When most Transitional Timing modes and sample rates are active, a 32-bit counter records each sample's elapsed time. The maximum value for each timestamp counter is...
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232 = 4,294,967,296
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Time Per Sample at 500 MHz = 2 nanoseconds
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Max Time Per Sample = 4,294,967,296 × 2 ns
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Max Time Per Sample = 8,589,934,592 ns
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Max Time Per Sample ≈ 8.589 seconds per sample
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Max Time Span Per Trace Capture = Total Samples × Max Time Per Sample
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Max Time Span (at 34M samples) = ≈ 9 Years Per Trace Capture
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Max Time Span (at 67M samples) = ≈ 18 Years Per Trace Capture
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Max Time Span (at 134M samples) = ≈ 36.6 Years Per Trace Capture
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So even if the timestamp counter for every sample in the trace capture reaches its maximum value during a 34M sample trace, the total time-span still covers about 9 years of time.
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Sampling at 500 MHz, the GoLogicPro captures all signal activity with 2 nanosecond resolution. The above figures demonstrate that relatively long periods of inactivity do not prevent capturing high-speed bursts of activity.
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Of course, the maximum time per sample and maximum time per trace capture increases as the Transitional Timing sample rate is slowed.
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A few Transitional Timing modes and sample rates reduce the timestamp counter bit-width to 26, 24, or 18 bits.
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226 = 67,108,864
224 = 16,777,216
218 = 262,144
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The timestamp counter bit-width exceptions are...
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Active Pod A at 1.6 GHz: 26-bit timestamps
Active Pod A, B, C, D at 500 MHz and slower: 24-bit timestamps
Active Pod A at 500 MHz and slower: 18-bit timestamps
Active Pod A & B at 950 MHz: 18-bit timestamps
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These smaller timestamps reduces each sample's maximum time as follows...
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226 = 67,108,864 x 625 ps (at 1.6 GHz) = 41.9 ms
224 = 16,777,216 x 2 ns (at 500 MHz) = 33,56 ms
218 = 262,144 x 1.05 ns (at 950 MHz) = 275.3 us
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These smaller timestamp limits mean that inactive signals cause the counter to "rollover" to zero sooner than a 32-bit timestamp.
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If this happens, the sample is stored to memory automatically even without any signal changes.
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Copyright and trademark information
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