Loading Binary Waveforms into ArbStudio. SampleRate. SampleRate 1GS LAB BRIEF LAB-913

Transcription

1 Loading Binary Waveforms into ArbStudio LAB BRIEF LAB-913 March 07, 2012 Summary It is possible to load and replay binary trc-files captured with a LeCroy oscilloscope with the ArbStudio arbitrary waveform generators. But the ArbStudio has a maximum memory length of 2MS per channel and a sample rate of max. 250MS/s. This application brief descibes how to circumvent these limits To load a saved binary waveform (*.trc-file) into ArbStudio you first have to know the memory length and sample rate of the waveform has been captured. If you don t know these details you have two possibilities to find this out. The first possibility is to use the LeCroy Software WaveStudio. WaveStudio is a free software from LeCroy capable to loading binary waveforms. You can download the software from the LeCroy homepage: Once you loaded the binary file into WaveStudio you can display the properties of the trace showing the Time/Div and the number of Data Points the signal has been captured. With these information you can calculate the sample rate. MemoryLength SampleRate 10 Time / Div In the following example the sample rate calculates as: 5MS SampleRate 1GS / s µs Figure 1: Read Memory Length and Time/Div with WaveStudio LeCroy Corporation Loading Binary Waveforms into ArbStudio page 1 of 5

2 The second possibility is to load the trace back into a memory of the oscilloscope. To find the number of Data Points you can make a parameter measurement NumPoints and calculate then together with the Time/Div value in the channel annotation box the sample rate. Figure 2: Load the signal into the oscilloscope to get the Memory Length and Time/Div Having now these information of the waveform there are four different possibilities which parameters have to be modified to be able to load a captured waveform into ArbStudio. 1. The Sample Rate is less or equal to 250MS/s and the number of Data Points is less or equal to 2MS The signal can be directly loaded into ArbStudio 2. The Sample Rate is less or equal to 250MS/s but the number of Data Points exceeds 2MS The number of Data Points needs to be reduced to max. 2MS 3. The Sample Rate is higher than 250MS/s and the number of Data Points is less or equal to 2MS The Sample Rate needs to be reduced to max. 250MS/s 4. The Sample Rate is higher than 250MS/s and the number of Data Points exceeds 2MS The Sample Rate and number of Data Points have to be reduced to max. 250MS/s and 2MS On the following pages we go through these four possible conditions explaining how to modify and load the signals into ArbStudio. LeCroy Corporation Loading Binary Waveforms into ArbStudio page 2 of 5

3 When Sample Rate and Memory Length fit the ArbStudio limits (case number 1.) there is no need to modify the signal. You only have to set the Sample Rate (Figure 3) and the number of Data Points which should be imported from the binary file (Figure 4). Figure 3: Set the Sample Rate of ArbStudio Figure 4: Set the number of Data Points The other three cases need to either reduce Sample Rate or number of Data Points of the binary file. This can be done with a WaveRunner Xi-A or Zi Family LeCroy oscilloscope using the math function Sparse. For not losing too much signal information by down sampling the signal with sparsing the factor should be calculated to the minimum suitable value. LeCroy Corporation Loading Binary Waveforms into ArbStudio page 3 of 5

4 For case 2 you need to reduce the number of Data Points of the signal. If we have for example a signal captured at a Sample Rate of 200MS/s but with 10M Data Points the needed Sparsing factor calculates as: Sparsing Factor= Memory Length max. Memory Length ArbStudio = 10MS 2MS = 5 Load the binary file into a memory of an oscilloscope and define a math function Sparse using the memory as input and set the calculated sparsing factor. Now you can save the math trace as new binary file which can be loaded into ArbStudio Figure 5: Set the Sparsing factor to reduce the number of Data Points Prior to loading the signal into ArbStudio you have to calculate the new Sample Rate because Sparsing reduces the Sample Rate. To have the signal replayed by ArbStudio with the correct signal frequency we need to change this setting in the ArbStudio software like described in Figure 3. The Sample Rate calculates in this example as: Sample Rate= original SR Sparsing Factor = 200MS/s = 40MS/s 5 LeCroy Corporation Loading Binary Waveforms into ArbStudio page 4 of 5

5 Looking at case 3 it is necessary to reduce the Sample Rate. In this example we captured a signal with 1M Data Points but at a Sample Rate of 5GS/s. Sparsing Factor = Sample Rate max. Sample Rate ArbStudio = 5GS/s 250MS/s = 20 Now you have to load the file into a memory of the oscilloscope, sparse the waveform and save the resulting waveform into a new binary file like described for case 2. Figure 6: Set the Sparsing factor to reduce the number of Data Points and thus the Sample Rate For loading this new file into ArbStudio you have to either measure or calculate the resulting number of Data Points. When measuring you can use the parameter NumPoints like in Figure 5 or use the following equation: Data Points= original Memory Length = 1MS Sparsing Factor 20 = 50kS For Case 4 you have to follow the instructions as described for cases 2 and 3. First change this parameter (Sample Rate or Memory Length) which will probably need the highest sparsing factor to meet the maximum limits of ArbStudio. After you calculated the first parameter check if the other parameter will fit as well using the same sparsing factor. LeCroy Corporation Loading Binary Waveforms into ArbStudio page 5 of 5