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| Hantek HDG2002B AWG: 5Mhz or 100MHz? Let's see! |
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| alex.forencich:
--- Quote from: IanJ on November 03, 2014, 09:09:27 pm ---Question about calibration.......... Am I right in saying you just hook up a volt meter to it's output and enter in all the voltages that appear at the output. It seems to throw a few voltages to me to start with but then did a whole load the same, even negative voltages till it completed. When I then tested......my amplitude is all over the place at various frequencies. Am I missing something with the procedure? Ian. --- End quote --- Use a scope. The unit needs calibration points at various frequencies to compensate for front end frequency dependence. |
| fremen67:
--- Quote from: Howardlong on November 03, 2014, 08:04:55 pm ---OK I answered my own a) and b) questions by looking at thr behaviour of the device at the already calibrated low frequencies. And, it wasn't that well calibrated! Firstly I did not use a 50 ohm termination because that wasn't the way the device was already cal'd. I also realised very quickly that it's not a very accurate 50 ohm impedance either, even at DC. For the first ten or so DC measurements I used a DVM, so far so simple. For the gazillions of other measurements I used an Agilent 54831d scope with a calibrated 10x probe coaxially fitted _directly_ into the AWG's output to avoid any standing waves problems due to non-termination at higher frequencies. I used the mean Vpp measurement on 10 averaged waveforms, and the measurement was reset each time, with the time base and vertical set appropriately as necessary. It took a long time, probably an hour or so just for one channel, but the results are excellent compared to how it was. However I've now realised there's a hardware filter tweak I possibly ought to have done first. By the way, make sure the AWG was set to sine wave on the channel in question before calibrating. Trying to calibrate on a square wave is no fun due to the overshoot when not terminated, and the cal procedure did not seem to reset this on my unit. --- End quote --- You did not let me enough time to reply :) I can't add a lot more as I did the same way: - sinus wave - no 50 ohm termination - a DVM for the 9 first values - My MSO5062D for the 3 sets of 27 values from 500kHz to 95Mhz, using average value on 16 samples - directly fitted in the HDG output - also took an hour for the first channel - gave up for the moment for channel 2 The results are now very accurate for DC values after calibration. For AC it is better as I can now go up to 100Mhz but I can see the impact on a change of output range on the HDG. There are small steps on the output after each change of range. I just run a self calibration on the MSO before calibration but my probe must not be very accurate. Regarding Wave generator, it was not working at all with FW 1.00.1 so I gave up and just used the software on the PC for that. I did not test it since I upgraded to FW 1.00.2 |
| fremen67:
--- Quote from: IanJ on November 03, 2014, 09:09:27 pm ---Question about calibration.......... Am I right in saying you just hook up a volt meter to it's output and enter in all the voltages that appear at the output. It seems to throw a few voltages to me to start with but then did a whole load the same, even negative voltages till it completed. When I then tested......my amplitude is all over the place at various frequencies. Am I missing something with the procedure? Ian. --- End quote --- From what I remember, only the 9 first values are DC. You need a scope for the others ( 3 sets of 27 values I think) I recommand that you write down all the values you measured at the same time you enter them... just in case you have to start again from the beginning |
| IanJ:
--- Quote from: fremen67 on November 03, 2014, 09:18:50 pm --- --- Quote from: IanJ on November 03, 2014, 09:09:27 pm ---Question about calibration.......... Am I right in saying you just hook up a volt meter to it's output and enter in all the voltages that appear at the output. It seems to throw a few voltages to me to start with but then did a whole load the same, even negative voltages till it completed. When I then tested......my amplitude is all over the place at various frequencies. Am I missing something with the procedure? Ian. --- End quote --- From what I remember, only the 9 first values are DC. You need a scope for the others ( 3 sets of 27 values I think) I recommand that you write down all the values you measured at the same time you enter them... just in case you have to start again from the beginning --- End quote --- Yep, managed to suss it out........great stuff!......and now I have a reasonably even amplitude for all freq up to 100MHz.....rather than tailing off severely not much above 20MHz. I'll go over it again more accurately now I know how it's done. Ian. |
| andrija:
I can confirm telnet over LAN works fine once you add the necessary parts and configure the (static) IP address. So you don't have to get a FTDI if you don't have already and can "upgrade" to 100MHz by editing the file via LAN. Just enter "root" as username (there's no password). |
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