Hello everyone, I graduated from college (Electronics Engineering) 8 months ago and have been working at Larsen and Toubro Embedded Systems and Software for the past 6 months. During the first few weeks of induction period, I had the opportunity of exploring the various Test and Measurement Instrument in our Labs. I started with the Tektronix TPS2024 oscilloscope (200MHz , 2 Gsps, Isolated grounds). After experimenting around a bit with the oscilloscope, I started capturing signals which we find in our labs quite frequently... Telephone, Rs232, I2C etc.. It was real fun to observe these in real life, specially after just learning about them at college. It was during this time that I was able to capture the Waveforms of
10Mbps Ethernet. Well since I dont have any real experience with such kind of things, I wanted to ask someone who knew all this stuff to tell me if the signals I captured were correct ones or not? I am also doubtful of the procedure of capturing the signals
Here is what I did: I stripped the insulaton of the TX+ and TX- wires in the CAT5 cable near one end of the cable (the one near the CPU). The other end went into a 10Mbps Hub. I used a 200MHz isolated channel oscilloscope to take the measurement of the differential signal on the TX+ and TX- wires. The Probes were set to 10X attenuation to keep the bandwidth up till 200 MHz
I tried the same measurement using different setups. The resultant waveforms are available at:
I have also referred to: ANSI-IEEE Std 1802.3d-1993 (Conformance Test Methodology for IEEE Standards for Local and Metropolitan Area Networks)
- Type 10BASE-T Medium Attachment Unit (MAU) Conformance Test Methodology (Section 6)
According to the waveform given at the start (page 10) of this document, it seems that what I captured is quite what is required but still I would like the comments and opinions of others.
I wasnt able to find much regarding waveforms of the ethernet signals thru gools so I would be happy if you would go through my findings and post in your comments.
Thanking you
Regards and best wishes for the new year
Anurag Chugh Larsen and Toubro EmSyS, Mumbai India