Tektronix TDS5032, Manual

Page: 210 / 248

Measurement Algorithms
Note: There must be three K-J pairs after chirp-K that are less than 500 µs. This
is to check the response of the device. The response time must be less than 100
µs. You can verify this manually.
Host Chirp Test
This test examines the basic timing and voltages of both upstream and
downstream ports during the speed detection protocol. To get the Chirp signal,
hot-plug the unit under test (Host) and measure the signaling with single ended
probes on both lines. The application analyzes data for the following:
Chirp Response Timing
Chirp-K and Chirp-J duration
The application analyzes data for the Chirp J/K to first SOF Time.
Monotonic Property Test
This algorithm calculates the number of monotonic violations that are present
from of the start of the signal to the end of packet (EOP). For the signal to be
monotonic, the signal is checked from 15% to 85% of the Peak to Peak
differential signal levels or user specified levels.
Monotonicity is calculated for Rising and Falling slopes as follows.
For Rising slope, f(x) is a differential signal if,
signal is monotonic for all values of x till the last data point.
196 TDSUSB2 Universal Serial Bus Measurement Package