Waveform Data Transfer Rates

Waveform Data Transfer Rates For Various Transfer Methods

This report documents both the performance of waveform data transfer rates for various transfer mediums and the methods used to determine the performance. The transfer mediums tested were: physical GPIB, LAN, and virtual GPIB. The intent is to measure and document the waveform data transfer rates.

The performance numbers will likely vary depending on the machine that the benching tests are being run on and the networking between the machine and prototype for physical GPIB and LAN. The benchmarking was performed with a waveform query benchmark tool written by Keith Rule. The Physical GPIB and LAN tests were run on my workstation (ew124705 which has a 1GHz Pentium with 256MB of RAM). I have a 100 Mbits switch that connects my workstation with prototype. Waveform transfer rates were measured with acquisitions stopped for three record lengths.

TDS5104 version 1.0.308 with an 800 MHz Celeron with 128 MB RAM.
Note: This version is not being shipped to customers yet. It will be part of our Maintenance Release coming later.

TDS5104 (v 1.0.308)	500 points		100,000 points		4,000,000 points
Physical GPIB	Average: 0.034 MBytes/s Max: 0.36, Min: 0.018		Average: 0.49 MBytes/s Max: 0.53, Min: 0.48		Average: 0.77 MBytes/s Max: 0.77, Min: 0.73
LAN	Average: 0.028 MBytes/s Max: 0.032, Min: 0.005		Average: 0.94 MBytes/s Max: 1.04, Min: 0.32		Average: 3.78 MBytes/s Max: 3.94, Min: 2.78
Virtual GPIB	Average: 0.040 MBytes/s Max: 0.041, Min: 0.004		Average: 5.50 MBytes/s Max: 5.80, Min: 0.82		Average: 12.0 MBytes/s Max: 14.2, Min: 5.79
TDS7054 (v 2.0.0027)		500 points		100,000 points		4,000,000 points
Physical GPIB		Average: 0.013MBytes/s Max: 0.015, Min: 0.009		Average: 0.70 MBytes/s Max: 0.70, Min: 0.63		Average: 0.78 MBytes/s Max: 0.78, Min: 0.78
LAN		Average: 0.013 MBytes/s Max: 0.015, Min: 0.008		Average: 1.60 MBytes/s Max: 1.60, Min: 0.20		Average: 2.70 MBytes/s Max: 2.86, Min: 2.22
Virtual GPIB		Average: 0.012 MBytes/s Max: 0.014, Min: 0.008		Average: 1.89 MBytes/s Max: 2.04, Min: 1.48		Average: 6.89 MBytes/s Max: 7.48, Min: 6.48

Test procedure:

The benchmarking tool’s executable should be located with this report.

The benchmarking tool has a number of settings. Generally the default setup was used for these tests. The "Priority Boost" feature was used for doing the Virtual GPIB testing. (This makes a big difference on the TDS5000 instruments.) The "Source:" was changed as needed to select physical GPIB or LAN testing. See the "Waveform Query" directory for source code. For LAN testing TekVisa must be installed on the workstation where the test will be run and a LAN connect must be setup using the TekVISA Configuration tool.

The scope was basically in the default setup. The horizontal scale was changed so that a 4,000,000 point waveform could be acquired at 1.25 GS/s.
For each transfer medium:
For physical GPIB there needs to be a GPIB connection between the instrument and the workstation.
For LAN there needs to be an ethernet connection between the instrument and the workstation.
For each record length:
1. The scope record length was changed and an acquisition was acquired and acquisition state was stopped.

2. The VISA Benchmark test program was started.
For physical GPIB and LAN the program is started on the workstation.
For virtual GPIB the program was started on the instrument.
3. The test is run for a couple minutes to make sure that it is running as expected. The transfers rates should updating.
4. Then the reset averages button is selected to reset the numbers.
5. The test is then run for a couple minutes to see that a average number is settling in. (At least for the virtual GPIB the average transfer rate varied between 11.5 and 12.5. So my results reported 12.)
6. The average, minimum and maximum transfer rates are recorded.