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I'm putting together a toy box of various parts, as I plan to make a self contained Q-meter. I'm just about to begin an RF sweep of the impedance converter / transformer driver. I used an isolated BNC

Hi Mikek, The attenuators should not alter "Impedance Converter" output impedance. The attenuators should have constant output impedance. Guessing attenuator impedance is 50 ohm, based on R1 = 56.2

For those playing along, Here is a drop box schematic put together from the Oscillator to the injection transformer. I was thinking it may help to see the impedances. I don't have a clue what the

Try calculating the output Z by measuring the chaange in outpuit V when terminated with small value resistor (of suitable power rating). John KK6IL

I am a little surprised that HP didn't put a .01 uF ceramic capacitor in parallel with that 22 uF electrolytic. Maybe it is a physically small tantalum? 73 (Regards). Max K 4 O D S. I've Never Lost

I may be premature in answering this question because it may have already been answered. The output impedance of an emitter follower is the source impedance driving the base divided by the current

Lots of 4342A manuals floating around - don't know why I had trouble finding one before. <https://xdevs.com/doc/HP_Agilent_Keysight/HP%204342A%20Operating%20%26%20Service.pdf> Mar 1983 version

Much better! I believe those numbers a lot more than the previous ones. And a low-MHz corner frequency (where the inductive component of the output impedance equals the resistive one) is about where

That should be "output impedance".??? :)

I finally have much better results! The Q1 input transistor makes all the difference. I've been trying various Q1's and have found several that work very well. Low end input impedance is now under one

Appended to bottom of: https://www.kn5l.net/Q-Meter/ is a Q-Meter prototype schematic proposal. For greatest accuracy, RF to injection transformer should have low impedance, proposing an AD8055 direct

---- Do you have a local bypass cap across the supplies? Preferably one large, one small cap in parallel. Ozan

If you don't want to install yet another program, https://djvu.js.org/ will do it in a web browser. At least it did for me in Firefox on a Mac. Very slow if you have it load the whole document in

I don't know why my measurement gives the higher than expected output impedance. I've confirmed the (calibrated) VNWA accurately measures a 0.2 ohm resistor. My breadboard is "ugly style, soldered

Is it possible to come up with a formula or spreadsheet that would calculate Q from 3db, with the caveat that instead of using 0.707, use the number 0.7 and normalize it to 3db? That would be great

Almost certainly neither is correct.??? The challenge will be to determine the uncertainty of each method, but even for simple instruments, working out the uncertainty is a non-trivial

That's what my 3db request was getting at. Thank, Mikek

Hi Mikek, Revisiting with my V-Meter prototype as shown in: https://www.kn5l.net/Q-Meter/ DUT = T50-2 37T #24 with 330pF C0G Different L C components. VNWA BW Q measurement = 211 for these parts.

Mikek, The HP-400E measured DUT uses same components as in the Prototype meter section. Within that section is "VNWA S21 Q Measurement" with Q = 229. John KN5L

Mikek, The SimSmith model is assuming an Ideal transformer, with no loss. The 50 points is a function of Generator 50 Ohm output impedance. Lower generator output impedance will reduced Q loss. A