Teledyne LeCroy QPHY-ENET - Manual (Page 25)

QPHY-ENET Software Option
QPHY-ENET Operator’s Manual Rev G
25
10Base-T DOV Mask and Voltage Test
The differential output voltage (DOV) is defined as the absolute value of the peak differential voltage measured
into a 100 Ω termination. The mask test evaluates the pulse shape.
The transmitter should be set to generate a Pseudo Random bit pattern of at least 511 bits in duration. This
type of pattern will repeat every 511 bits or more so that over a shorter measurement time, the data will appear to
be random.
Note: The method for setting the Device Under Test into transmit mode is device specific. Contact your PHY chip vendor for information on
how to do this.
Figure 14. Fixture setup for 10Base-T mask test
1. Connect DUT to J13 at section A of TF-ENET-B by using a short RJ45 cable included with TF-ENET-B
package. Remove jumpers J7, J8, J9, J10, J20, J21, J22, J23, and install jumpers J1, J6, J14, J16, J24,
J25, to test for TPM 100 Ω.
2. Connect oscilloscope channel 2 to J84, channel 3 to J85 (
X
Figure 14
X
, previous).
3. Touch the 10Base-T button under “Select Standard.”
4. Select the appropriate mask from the “Select Test” field:
• DOV Mask MAU Ext for external MAU testing
• DOV Mask MAU Ext Inv for external MAU testing of the negative-going pulses
• DOV Mask MAU Int for internal MAU testing
• DOV Mask MAU Int Inv for internal MAU testing of the negative-going pulses
Only two of the four masks above will be used for any given device (either internal or external MAU). Both
positive and negative-going pulses must be tested.
5. Check the Differential Data on 2 Channels checkbox to enable probing with two separate channels and
enter C2 in Source for + Data, C3 in Source for - Data field.