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The Video Display Clamp

4

013-0278-00 Video Display Clamp

Video display clamp

Figure 5: Probing circuits with the video display clamp

Use the following short procedure to install and use the Video Display Clamp.
Attaching the video display clamp to an oscilloscope with a TEKPROBE

TM

Level 2 interface automatically turns on the video display clamp.

STOP

. The use of this clamp requires that the test oscilloscope has a TEK-

PROBE

TM

Level 2 interface and the vertical input impedance is 1 M

Ω

.

1.

Attach the video display clamp to the input of the oscilloscope and apply the
test signal to the input of the video display clamp. See the examples
provided in Figures 3 through 5.

2.

Set the input impedance of the oscilloscope to 1 M

Ω

.

3.

Set the

SYNC POLARITY

of the video display clamp to match the polarity

of the signal source.

H

Set to

--

for video signals with negative sync pulses.

H

Set to

+

for video signals with positive sync pulses.

4.

Set the

CLAMP FILTER

of the video display clamp.

H

Set to

OFF

for video signals without a color burst signal.

H

Set to

ON

for video signals with a color burst signal.

5.

Set the controls of the test oscilloscope as you normally would to view the
signal.

Procedure

Summary of Contents for 013-0278-XX

Page 1: ...Instructions 013 0278 XX Video Display Clamp 070 8762 01 P070876201 070876201 www tektronix com...

Page 2: ...nd pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved TEKTRONIX and TEK are registered trademarks of Tektr...

Page 3: ...charges duties taxes and any other charges for products returned to any other locations This warranty shall not apply to any defect failure or damage caused by improper use or improper or inadequate m...

Page 4: ......

Page 5: ...n 1 Features 2 Using the Video Display Clamp 2 Specifications 5 Performance Verification 7 General Instructions 7 Conventions 7 Equipment Required 7 Procedures 8 Back Porch Correction Check 8 Gain Err...

Page 6: ...in check 13 Figure 11 Crosstalk test setup 14 Figure 12 Measuring interference 15 Figure 13 Measuring timing intervals 15 Figure 14 Bandwidth test setup 16 Figure 15 60 Hz rejection test setup 18 Figu...

Page 7: ...grounding conductor must be connected to earth ground Before making connections to the input or output terminals of the product ensure that the product is properly grounded Observe All Terminal Rating...

Page 8: ...that could result in damage to this product or other property These terms may appear on the product H DANGER indicates an injury hazard immediately accessible as you read the marking H WARNING indicat...

Page 9: ...into the environment and to reduce the use of natural resources we encourage you to recycle this product in an appropriate system that will ensure that most of the materials are reused or recycled app...

Page 10: ...Environmental Considerations vi 013 0278 XX Video Display Clamp...

Page 11: ...t make it difficult to view the video signal with an oscilloscope The Video Display Clamp provides a stable signal to the oscilloscope by clamping the back porch of the video signal to ground referenc...

Page 12: ...ures Features of the video display clamp other than setting the back porch to ground reference include the following items CLAMP FILTER When ON the Video Display Clamp ignores the presence of a color...

Page 13: ...to a video signal line with a T connector to monitor the signal without causing loading interference to the signal see Figure 4 H Connect a 1X probe directly to the video display clamp to probe video...

Page 14: ...ach the video display clamp to the input of the oscilloscope and apply the test signal to the input of the video display clamp See the examples provided in Figures 3 through 5 2 Set the input impedanc...

Page 15: ...cs Signal Input Impedance Return Characteristics Name Description Input Resistance Only applies when the video display clamp is operating 15 k Table 3 Warranted Characteristics Video Display Clamp Nam...

Page 16: ...625 50 2 1 1250 50 2 1 625 50 1 1 1250 50 1 1 787 59 94 1 1 Offset Error 16 mV The difference between the back porch and ground Offset error may increase up to 40 mV for certain standards such as 787...

Page 17: ...istics Table 7 lists the required test equipment Table 7 Test Equipment Item Number and Description Minimum Requirements Example Purpose 1 Oscilloscope TEKPROBETM Level 2 interface 100 MHz bandwidth T...

Page 18: ...eristics in the Specifications section These procedures check those characteristics that relate to the back porch correction capability of the Video Display Clamp listed as checked under Warranted Cha...

Page 19: ...s viewed with channel 2 H Set the compliment to H Adjust the period to 15 kHz H Adjust the pulse duration to 5 s H Set the high level to 1 0 volts H Set the low level to 0 75 volts 4 Set the Video Dis...

Page 20: ...e to display channel 2 channel 1 off 8 Set the pulse generator as follows H Set the high level to 0 8 volts H Set the low level to 1 0 volts H Set the compliment to 9 Set the Video Display Clamp Polar...

Page 21: ...ne precision coaxial cable Item 2 one 2 5X attenuator Item 4 one 50 terminator Item 3 and one dual input coupler Item 5 1 Set the test oscilloscope as follows H Set the sec div scale to 10 s H Set the...

Page 22: ...compliment to H Adjust the period to 15 kHz H Adjust the pulse duration to 5 s H Set the high level to 500 mV H Set the low level to 500 mV 4 Set the Video Display Clamp as follows H Polarity to negat...

Page 23: ...oscope Item 1 one pulse generator Item 8 one precision coaxial cable Item 2 one 2 5X attenuator Item 4 and one 50 terminator Item 3 and one dual input coupler Item 5 1 Set the test oscilloscope as fol...

Page 24: ...lse generator as follows H Set the compliment to H Adjust the period to 15 kHz H Adjust the pulse duration to 5 s H Set the high level to 0 V H Set the low level to 300 mV 4 Set the Video Display Clam...

Page 25: ...then back to negative 8 Verify that the pulse display returns to its original position within 1 mV 9 Set the test oscilloscope sec div scale to 500 ns 10 Using Figure 13 as a reference measure the ti...

Page 26: ...cale to 10 ns H Set the channel 1 and channel 2 volts div scales to 200 mV AC coupled H Position both the channel 1 and channel 2 traces to center screen H Display channel 2 channel 1 off 2 Connect th...

Page 27: ...t Required One test oscilloscope Item 1 one pulse generator Item 8 one sinewave generator Item 7 one 2 5X attenuator Item 4 two dual input couplers Item 5 and one precision coaxial cable Item 2 1 Set...

Page 28: ...Set the frequency to 60 Hz H Adjust the amplitude to 0 V 5 Set the pulse generator as follows H Set the compliment to H Adjust the period to 15 kHz H Adjust the pulse duration to 5 s H Set the high l...

Page 29: ...l channel 1 Figure 16 60 Hz rejection check negative 10 Set the compliment of the pulse generator to 11 Set the Video Display Clamp Polarity to positive 12 Verify that the amplitude of the 60 Hz sinew...

Page 30: ...Performance Verification 20 013 0278 00 Video Display Clamp...

Page 31: ...arest Tektronix Field Office or representative Use the following procedure to replace a damaged contact pin 1 Using a pair of needle nosed pliers grasp the damaged pin and pull the pin straight out of...

Page 32: ...Maintenance 22 013 0278 00 Video Display Clamp...

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