Teledyne-lecroy QPHY-DDR4 Instrukcja Użytkownika Pobierz pdf (Strona 64)

tDQSH/tDQSL, DQS Input High/Low Pulse Width

These tests measure the high (tDQSH) and low (tDQSL) pulse widths of each DQS signal during a W

burst. Both the maximum and minimum tDQSH/tDQSL values are measured.

This tests are very similar to

tQSH and tQSL, which are measured on R bursts.

Note: Only tDQSH will be discussed below. The measurement methodology is the same for the

tDQSL expect the measurement is made on DQS from falling edge to a rising edge instead of a rising

edge to a falling edge.

After the completion of the tDQSH test the oscilloscope is in the following configuration:

Figure 55 - Oscilloscope Configuration after the tDQSH test

Shown on this screen:

• Z2 is a zoom of F2, the acquired DQS signal after any probe deskew has been applied. The zoom is

positioned at the location of the “worst case” tDQSH measurement indicated by t@tDQSHmin. A

trace label is applied at Vref on this trace according to the signal name assigned to DQS.

Figure 56 – tDQSH/tDQSL Results

64 924291 Rev A

1 2 ... 59 60 61 62 63 64 65 66 67 68 69 ... 72 73

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Teledyne-lecroy QPHY-DDR4 Instrukcja Użytkownika Strona 64