Tektronix VX4287, User Manual

Page: 169 / 180

Appendix F: Performance Verification
VX4287
A–35
This sequence verifies DC Common Mode Rejection to be >50 dB.
Equipment
Requirements DC Voltage Calibrator (item 4)
BNC Coaxial Cable, one (item 6)
BNC female to Clip Lead Adapter (item 8)
BNC Dual Banana Connector (item 10)
Small Alligator Clip (item 11)
Prerequisites All prerequisites listed on page A–22
1. Attach the DD-50S Interconnect Assembly to P4 as shown in Figure 5.
2. Short together the 0-to-7 positive and negative input channels with a small
alligator clip.
3. Connect the Voltage Calibrator to input channels 0-to-7 using a Dual-Banana
connector a Coaxial cable, and a BNC to Clip Lead adapter. Attach the red
Clip Lead to the shorted positive and negative input channels and the black
Clip Lead to GND (P4-pin 42).
4. Set the Calibrator to +50.0 V DC.
5. Using the following commands, set the VX4287 to the power-on default
state, to close the designated isolation relays, to make a voltage measurement
on the specified channels (0-to-7 in this first pass; 8-to-15, 16-to-23,
24-to-31 on subsequent passes), to use the high voltage range, and to report
the results using labels.
(8-15, 16-23, 24-31 later passes)
6. Perform nine successive acquisitions and verify that all responses (AVE,
MIN, MAX for the eight channels) are
≤
174 mV (50dB = 20*log[49/.174] ).
(The ninth response, NO ADDITIONAL ERRORS, is to ensure that all data
from the Event buffer has been read back. For controllers that do not support
successive read back, the VOLTNEXT? command may be sent between
readings.)
(Verify responses to be
≤
174 mV)
(Verify responses to be
≤
174 mV)
7. Set the Calibrator to –49.0 V DC.
8. Reacquire and verify the responses to be
≤
174 mV.
(use 8-15, 16-23, 24-31 on other passes)
(Verify responses to be
≤
174 mV)
DC Common Mode
Rejection