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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 4:19 am 
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ttx450cap wrote:
as specific as I can be-cheers cannot even see the photo?

Which photo? The diagram in my post?

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 4:28 am 
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ttx450cap wrote:
stevebyan wrote:
Does your function generator have a separate output of the modulating signal? If it doesn’t, you can’t easily make a trapezoidal display of the signal.

yes, just for 1Hz out, doing the the setup for cal., I needed to use the High output as in screen-shoot-cal manual?

I can’t understand what you are trying to say. It doesn’t make sense that your function generator has only a 1 Hz modulating signal. And I don’t understand what “doing the setup for the cal” has to do with whether your function generator has a separate output for the modulating signal. Nor do I understand your question about “needing to use the High output”.

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 8:35 pm 
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stevebyan wrote:
ttx450cap wrote:
is this what you are asking? took this pict yesterday before the x-y picts above.. slowed the sweep down, believe its in 2vdiv.

Yes, that’s what I meant when I asked you to slow down the sweep.

The drawing I posted tells you exactly how to calculate the percentage modulation from that scope display.


hi.. thanks I am getting somewhere..

I cannot read this picture even with my super cheaters on. link?


Attachments:
scan12.jpg
scan12.jpg [ 73.65 KiB | Viewed 86 times ]

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 8:42 pm 
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stevebyan wrote:
ttx450cap wrote:
stevebyan wrote:
Does your function generator have a separate output of the modulating signal? If it doesn’t, you can’t easily make a trapezoidal display of the signal.

yes, just for 1Hz out, doing the the setup for cal., I needed to use the High output as in screen-shoot-cal manual?

I can’t understand what you are trying to say. It doesn’t make sense that your function generator has only a 1 Hz modulating signal. And I don’t understand what “doing the setup for the cal” has to do with whether your function generator has a separate output for the modulating signal. Nor do I understand your question about “needing to use the High output”.


I was playing around trying to cal my function generator for a change of pace. Calibrate - meaning cal my FG, for cal it said turn on 50% mod & cal that section connected through the FG hi-output to scope to adjust 50% mod. sorry maybe to many coronas, get a little sloppy in my typing.. thks for your help.

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 9:13 pm 
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ttx450cap wrote:
I cannot read this picture even with my super cheaters on.

The image is a link to the original. It is rather low resolution, but when I scale it up in my browser, I can read it. Here's what it says:

The smaller signal, either the valleys of the waveform on the left side of the diagram, or the left side of the trapezoid on the right side of the diagram, is named "Emin". The larger signal, the peaks of the waveform or the right side of the trapezoid, is named "Emax".

The formula for percent modulation at the bottom of the diagram is:

Code:
         Emax - Emin
% MOD = ------------- x 100
         Emax + Emin

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 9:30 pm 
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stevebyan wrote:
ttx450cap wrote:
I cannot read this picture even with my super cheaters on.

The image is a link to the original. It is rather low resolution, but when I scale it up in my browser, I can read it. Here's what it says:

The smaller signal, either the valleys of the waveform on the left side of the diagram, or the left side of the trapezoid on the right side of the diagram, is named "Emin". The larger signal, the peaks of the waveform or the right side of the trapezoid, is named "Emax".

The formula for percent modulation at the bottom of the diagram is:

Code:
         Emax - Emin
% MOD = ------------- x 100
         Emax + Emin


thanks.. website must strip the link as I have clicked on it many times and nothing. but anyways thanks
looks like the ave of mod above no mod?

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 9:50 pm 
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ttx450cap wrote:
looks like the ave of mod above no mod?

Yes

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 10:02 pm 
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stevebyan wrote:
ttx450cap wrote:
looks like the ave of mod above no mod?

Yes


max mod is the units max output at a spec voltage (level) then?

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 11:03 pm 
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stevebyan wrote:
ttx450cap wrote:
looks like the ave of mod above no mod?

Yes

Sorry, I was wrong.

The average of Emax and Emin is the peak voltage of the unmodulated carrier. The peak-to-peak voltage is twice that.

The difference between Emin and Emax is the peak-to-peak voltage of the modulation.

Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

Edit:
I'm wrong again. See my post below.

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Last edited by stevebyan on Oct Mon 26, 2020 1:51 pm, edited 1 time in total.

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sat 24, 2020 11:22 pm 
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stevebyan wrote:
stevebyan wrote:
ttx450cap wrote:
looks like the ave of mod above no mod?

Yes

Sorry, I was wrong.

The average of Emax and Emin is the peak voltage of the unmodulated carrier. The peak-to-peak voltage is twice that.

The difference between Emin and Emax is the peak-to-peak voltage of the modulation.

Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of the peak-to-peak carrier voltage.


so peek to peek? both ac/dc are coming out the same with just a light voltage shift when I switch between ac/dc on scope? my scope might not be reading right...

analog sure make some nice waves on a tube.. is this the right way to look at this pattern up close to view it for mod? 2vdiv

will need to re-look at it for peek to peek..


Attachments:
eci_fg_no_mod2vdiv.jpg
eci_fg_no_mod2vdiv.jpg [ 668.15 KiB | Viewed 70 times ]
eci_fg_50%mod_2vdiv.jpg
eci_fg_50%mod_2vdiv.jpg [ 676.69 KiB | Viewed 70 times ]

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sun 25, 2020 8:42 pm 
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stevebyan wrote:
ttx450cap wrote:
looks like the ave of mod above no mod?

Yes


believe I got it.. hard to read my scope that low, but should be 50%mod or very close.
thks......

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Sun 25, 2020 10:33 pm 
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ttx450cap wrote:
is this the right way to look at this pattern up close to view it for mod?

No. This is the usual way, except you might want to go to a little faster sweep speed:
Image

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Mon 26, 2020 12:30 am 
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stevebyan wrote:
ttx450cap wrote:
is this the right way to look at this pattern up close to view it for mod?

No. This is the usual way, except you might want to go to a little faster sweep speed:
Image

ok, thanks..

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Mon 26, 2020 2:13 pm 
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stevebyan wrote:
The average of Emax and Emin is the peak voltage of the unmodulated carrier. The peak-to-peak voltage is twice that.

The difference between Emin and Emax is the peak-to-peak voltage of the modulation.

Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

Sorry, I was wrong again. Corrections in italics:

Percent modulation is the peak voltage (half of the peak-to-peak) of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

This is because at 100% modulation, the carrier is completely cut off at the negative peak of the modulation, and the carrier is doubled at the postitive peak of the modulation. Therefore the peak of the modulation is equal to the peak-to-peak of the carrier at 100% modulation.

An algebraically equivalent way of phrasing it, which corresponds to the formula given earlier, is:
Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of twice the peak-to-peak carrier voltage.

The peak-to-peak carrier voltage is (Emax + Emin) / 2, so twice the peak-to-peak carrier voltage is just Emax + Emin.

The peak-to-peak voltage of the modulation is just Emax - Emin.

Hence, % mod = (Emax - Emin) / (Emax + Emin)

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Mon 26, 2020 8:17 pm 
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stevebyan wrote:
stevebyan wrote:
The average of Emax and Emin is the peak voltage of the unmodulated carrier. The peak-to-peak voltage is twice that.

The difference between Emin and Emax is the peak-to-peak voltage of the modulation.

Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

Sorry, I was wrong again. Corrections in italics:

Percent modulation is the peak voltage (half of the peak-to-peak) of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

This is because at 100% modulation, the carrier is completely cut off at the negative peak of the modulation, and the carrier is doubled at the postitive peak of the modulation. Therefore the peak of the modulation is equal to the peak-to-peak of the carrier at 100% modulation.

An algebraically equivalent way of phrasing it, which corresponds to the formula given earlier, is:
Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of twice the peak-to-peak carrier voltage.

The peak-to-peak carrier voltage is (Emax + Emin) / 2, so twice the peak-to-peak carrier voltage is just Emax + Emin.

The peak-to-peak voltage of the modulation is just Emax - Emin.

Hence, % mod = (Emax - Emin) / (Emax + Emin)


I closed the case and put it back on the shelve :shock: calibrated with my non-cal eq., but I do so more to learn, can always re-cal when I get better eq. now you have my curiosity up, I will firer it up and check again and see how close it is. Many of the adj pots, like much of the older stuff.. you can feel a spot where the wiper sat for many years.. :( thks again..

p.s. setup say to adj pot R155 for 50% mod. then connect scope to EXT MOD out, check for 1 Vp-p sine out. Check? the only way to adjust is R155 mod level that I know of. Will see where this ends up after re-checking.

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Last edited by ttx450cap on Oct Mon 26, 2020 11:16 pm, edited 1 time in total.

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Mon 26, 2020 9:06 pm 
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if I read everything correctly and calculated correctly.. I am at 48.5%mod from last adjustment. I set it more to the 1v p-p yesterday, and if right it is very close to 50% mod. I can sleep on that until I get something more accurate to test this stuff on. thks

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 Post subject: Re: ECI fuction gen 40600 cal question
PostPosted: Oct Mon 26, 2020 9:16 pm 
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stevebyan wrote:
stevebyan wrote:
The average of Emax and Emin is the peak voltage of the unmodulated carrier. The peak-to-peak voltage is twice that.

The difference between Emin and Emax is the peak-to-peak voltage of the modulation.

Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

Sorry, I was wrong again. Corrections in italics:

Percent modulation is the peak voltage (half of the peak-to-peak) of the modulation expressed as a percentage of the peak-to-peak carrier voltage.

This is because at 100% modulation, the carrier is completely cut off at the negative peak of the modulation, and the carrier is doubled at the postitive peak of the modulation. Therefore the peak of the modulation is equal to the peak-to-peak of the carrier at 100% modulation.

An algebraically equivalent way of phrasing it, which corresponds to the formula given earlier, is:
Percent modulation is the peak-to-peak voltage of the modulation expressed as a percentage of twice the peak-to-peak carrier voltage.

The peak-to-peak carrier voltage is (Emax + Emin) / 2, so twice the peak-to-peak carrier voltage is just Emax + Emin.

The peak-to-peak voltage of the modulation is just Emax - Emin.

Hence, % mod = (Emax - Emin) / (Emax + Emin)


can I use this newer :shock: 20-30yr old transistor FG on IC circuits if I keep the output V down, I am sure that's a loaded question?

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