| General > General Technical Chat |
| The Rigol DS1052E |
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| tinhead:
funny, the input circuit is not much different than the one from Tekway DSO: https://www.eevblog.com/forum/index.php?topic=1571.msg21235#msg21235 The small ADC driver chip is in a LLP-8 package seems to be really LMH6552 (maybe hard to see on my picture but it is marked 88AB / 6552) |
| EECrAZY:
Yeah, looks like Tekway is a improved copy of Rigol with some changes on ADC/FPGA/LCD part. Analog inputs are just routed differently and all that trigger support circuitry looks also very similar with the same parts... I am still curious what is all that circuitry is supposed to do? Would not 1 comparator be enough? I noticed there is a LT1790 reference chip, I thought it could be used for self calibration, but turns out like it feeds a REF pin of LTC2601 DAC. Rigol board does not have those parts. There are a few analog multiplexers there with -1Db drop at 100Mhz, Could that be a bottleneck? Seems like the rest of the components would handle 200Mhz+ not a problem |
| EECrAZY:
--- Quote from: tinman on October 31, 2010, 06:28:39 pm ---that's the self-calibration unit, it runs with 125Mhz. --- End quote --- Do you mean that it has a 125Meg oscillator on board which is used for the sole purpose of selfcalibration??? |
| tinhead:
--- Quote from: EECrAZY on October 31, 2010, 10:58:11 pm --- --- Quote from: tinman on October 31, 2010, 06:28:39 pm ---that's the self-calibration unit, it runs with 125Mhz. --- End quote --- Do you mean that it has a 125Meg oscillator on board which is used for the sole purpose of selfcalibration??? --- End quote --- i've answered here: https://www.eevblog.com/forum/index.php?topic=1571.msg22123#msg22123 let's leave Rigol thread only Rigol related (even if probably Rigol is using the same self-calibration way but with different DAC) |
| EECrAZY:
Ok, finally took my rigol apart, warranty sticker removes very easily using the same method people use on xbox. Measured some signals, there is a small DAC chip with "D5G" marking. Looks like its constantly fed by CPU/FPGA, so the output is steps of different height. DAC output feeds two 4051 multiplexors, which are being switched by 8khz counter. I am wondering if they use this approach to generate offset voltages, trigger levels etc with only 1 DAC? |
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