Week 9: Scopes and Transfer Speeds

This week we took a closer look at the available oscilloscopes in the lab as well as the new Kphotonics compact femtosecond laser module. It reportedly has components to make it highly stable at a lower cost. Specifications include a center wavelength of 1560 nm, a pulse duration of < 100 fs, an output power of > 100 mW, and a repetition rate of 10 - 100 MHz. 

To detail the oscilloscopes, the one currently used in the system is the Tektronix DSA72004C rated at 20 GHz, 100 GS/s. The two alternatives are a Tektronix TDS6804B and MSO54. These are rated at 8 GHz, 20 GS/s and 1 GHz, 6.25 GS/s respectively. As previously mentioned, the oscilloscope in use does not perform to its rated data transfer speeds. Additionally, it was found that it produced “ghost” waveforms of both the lower and higher end spectrums sourced by the two probes. Examples of these occurrences can be found below. 

When considering which oscilloscope to use going forward, the important factors reside in the rated bandwidths and sample rates. Too little bandwidth can produce distorted measurements whereas too much can pick up unnecessary noise. High sample rates are desired to capture more information on the waveform such as frequency, rise and fall times, height and shape, and any irregularities. Further research is required in order to find the best medium for our system in addition to preventing another bottleneck prior to GPU implementation.

Data Transfer Speeds - Trevor Wong

In order to get the best transfer speeds possible with our current hardware, I decided to take the time to research different types of connectors and ports we have available. The Taichi X570 motherboard contains multiple ports with their own rated max data transfer speed: one Ethernet at 1Gb/s, eight 3.2 Gen1 USB-A at 5Gb/s, one 3.2 Gen2 USB-A at 10Gb/s, and two 3.2 Gen2 USB-C at 10Gb/s. The initial plan was to obtain a 10Gb/s wired network adapter to allow a 10Gb/s Ethernet connection in the future, however with access to the 3.2 Gen2 USB ports which are rated at the same speeds, it may no longer be necessary. In terms of the oscilloscope ports, all three contain a 1Gb/s Ethernet port and several 2.0 USB-A ports rated at 480Mb/s. The newest oscilloscope contains two 3.0 USB-A ports which can transfer data up to 5Gb/s. Due to these available ports, we are limited by the oscilloscopes’ max potential transfer speeds, the older two being at 1Gb/s (the DSA72004C scope is damaged and limited to 100Mb/s), and the newest one being at 5Gb/s. Although the newest oscilloscope has the highest potential transfer speeds, the drawback is the low bandwidth of the scope as stated by Alex. A decision matrix will need to be created to determine the best configuration for the current system.

For this week, we have assembled all the parts for the new PC and plan to build it tomorrow, November 12th. We will then proceed to verify component functionality and then continue on into replacing the current PC and connecting it to the system.