On the HPHV regulator manuel
www.euronet.nl/~aespreng/Shuntregv11d/Manual.pdf
There are 2 graphs.
1. Gain Vs Frequency
2. Phase Vs Frequency
Does anyone know how the second curve can be measured?
www.euronet.nl/~aespreng/Shuntregv11d/Manual.pdf
There are 2 graphs.
1. Gain Vs Frequency
2. Phase Vs Frequency
Does anyone know how the second curve can be measured?
Google "small signal loop stability measurement" or some such -- you insert a 50 ohm resistor into the control loop and, with a 50 ohm transformer to isolate your spectrum analyzer from the power supply), measure the gain and phase with a spectrum analyzer or phase-gain meter.
you can do all of this in DSP -- or with a digital scope -- the transformer needs sufficient bandwidth however -- probably from a few hundred Hertz to several hundred thousand. I know that Softwire has an FFT function which renders both magnitude and phase -- should be the same in LabView.
ok, i'm going to guess that you don't have a $10,000 spec analyzer -- you can measure the gain with a sweep generator and an ordinary scope --
If you want to measure phase in "analog" here's the technique used by Hewlett Packard in their 3567 phase-gain meter -- (and intersil wrote an interesting application note on their site which will measure phase acurately to 10 MHz ( http://www.intersil.com/data/an/an9637.pdf ), Audio Amateur had a similar article sometime in the early 1980's -- take a pair of high speed comparators and measure the difference in zero-crossing time by summing the voltage -- the integrated value will give you a voltage proportionate to phase.
The devices in the Intersil article are pretty hard to get -- but I have used the technique with both the HFA3102 in SOIC and with through-hole NPN transistors -- used Texas Instruments selectable-output current feedback opamps.
you can do all of this in DSP -- or with a digital scope -- the transformer needs sufficient bandwidth however -- probably from a few hundred Hertz to several hundred thousand. I know that Softwire has an FFT function which renders both magnitude and phase -- should be the same in LabView.
ok, i'm going to guess that you don't have a $10,000 spec analyzer -- you can measure the gain with a sweep generator and an ordinary scope --
If you want to measure phase in "analog" here's the technique used by Hewlett Packard in their 3567 phase-gain meter -- (and intersil wrote an interesting application note on their site which will measure phase acurately to 10 MHz ( http://www.intersil.com/data/an/an9637.pdf ), Audio Amateur had a similar article sometime in the early 1980's -- take a pair of high speed comparators and measure the difference in zero-crossing time by summing the voltage -- the integrated value will give you a voltage proportionate to phase.
The devices in the Intersil article are pretty hard to get -- but I have used the technique with both the HFA3102 in SOIC and with through-hole NPN transistors -- used Texas Instruments selectable-output current feedback opamps.
janneman said:
Not bad for a $24 chip --
btw, you can sometimes purchase an HP3575 for less than $50 on EBay -- then you don't have to do any soldering. (There's one running for about $10 as we speak.)
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