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IIUC, the Bodnar pulser does not output a flat waveform ¨C all design effort went into getting the fastest possible rise. 067-0521 and 106 put out a flat waveform.
Dave Wise From: [email protected] <[email protected]> On Behalf Of PMF via groups.io Sent: Thursday, April 28, 2022 1:59 PM To: [email protected] Subject: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? I started to use my recently received Leo Bodner Fast Rise Pulse Generator (BNC) on my Tek 547/1A1 before wondering if I should seek advice here. I will stipulate that I had looked through the archive for hints as to how to set it up to adjust the H.F. response of the vertical amplifier and will also stipulate that I had remembered to install a 50-ohm terminator between it and the 1A1 input. While reading many interesting tangents and helpful hints, I didn't see anything about using the Bodner on lower bandwidth scopes such as mine. Perhaps, this is an important hint, come to think of it. . . Would my trying to flatten the top of the square wave with the input Volts/Div. set at 0.2, sweep at .1 microsecond, which is the fastest on this dear old beast, and magnifying the sweep by 5 yield valid results? The test result sheet included with the Bodner shows the amplitude at 0.891 volts, Risetime at 36.02 pS, Falltime at 31.14 pS, overshoot at 3.2%, and undershoot at 5.6%. (Risetime of the 547/1A1 is supposed to be 7 nS.) Viewing the waveform with these settings showed some problems with the top of the square wave that did not appear when I put the Volts/Div. at .5 or 1 (don't quite remember which, now). Not magnifying the sweep made the wave form look like that of the Tek 106 output on a 310A scope. I would also note that the only 547 manuals that I have or have seen on TekWiki show this step only using the 067-0521-00/TU-7/1M1, rather than the 106 and a 1A1. While I have a 067-0521-00 and think that it has allowed me to peak the HF response fairly well, it could be well out of calibration. It also does not check the whole signal chain as would using the Bodner or the 106 with the 1A1 would - not to state the obvious. Also, I have no way of confirming the accuracy of the 067-0521-00 output because the 453 and 547 are my fastest scopes. Only other ones that I have are the 310As, which I would like to calibrate, too. (Like others here, I work in the AF range, admire the quality of these scopes, and haven't really needed anything modern, although the maintenance of these antiques has tried my patience a few times in the last few months.) My rationale for using the Bodner is to confirm function of this and my 453 vertical amplifiers before undertaking any (additional) attempts to adjust the output of my 106 and 107 Square Wave Generators. (I had chimed in on attempts to repair another party's 106 earlier this year.) I cannot tell if both of those generators are the source of various waveform distortions or if both of my scopes are the culprit. Initial adjustments on the 547 did allow me to almost flatten the top of the square wave, but I would like to try to improve the results - if I am on the right track. PMF |
