Time-Appliances-Project / Time-Appliances-Project/Time-Card
Connecting 1PPS and 10MHz outputs with 50 Ohm termination to another TimeCard 1PPS and 10MHz inputs
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Description
Seems that the 3.3V bidirectional drivers connected to the SMA connectors of one TimeCard in output mode can not be connected to another TimeCard input with 50 Ohm termination since 0.53.3V is lower then Input HIGH (0.653.3V) level specified for nc7wv125-d.
I may oversee something but a signal generator with a configuration of 3.3V square wave signal will generate 3.3V pulses with the termination resistor connected while the TimeCard output will be only half of that.
Is this intended?
[1] https://github.com/opencomputeproject/Time-Appliance-Project/blob/master/Time-Card/HW/ECAD/Latest/TimeCardV9_Schematic_8-28-2023.pdf
[2] https://www.onsemi.com/download/data-sheet/pdf/nc7wv125-d.pdf
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Research direction
Review the TimeCardV9 schematic in the linked PDF and the NC7WV125-D datasheet. Compare the 1PPS and 10MHz SMA driver and receiver specifications under 50 Ohm termination, then determine whether the observed voltage is intended. Done means the electrical behavior and any required design change or usage constraint are clearly documented.
Written by the indexing model from the issue text.
Assessment
- Domain
- embedded-iot
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100